What is the reason for oligohydramnios? Oligohydramnios during pregnancy: causes and consequences

Every woman dreams that her pregnancy will proceed easily and naturally, so that no one and nothing can distract the expectant mother from pleasant thoughts about her unborn child. However, in reality, not everything is so smooth.

One of the serious complications can be oligohydramnios. We will tell you what it is and how to treat it in this article.

What it is?

In a broad sense, oligohydramnios refers to a decrease in the amount of amniotic fluid from the norms characteristic of a particular stage of pregnancy. However, in the classical sense of the word, oligohydramnios is considered to be a small amount amniotic fluid on the eve of birth, at about -40 weeks.

When there was no ultrasound, and one could only guess about the amount of water, oligohydramnios was actually determined just before birth. Now, thanks to the development of diagnostics, it is possible to identify a tendency towards a decrease in water in the amniotic sac can be observed as early as 16 weeks.

Water is necessary for the normal development of a child. They are also a shock absorber provided by nature, softening shaking and swaying, which the baby could quite significantly feel when walking or other actions of the pregnant woman, if the waters did not interfere with this.

Amniotic fluid begins to be produced around the 8th week of pregnancy, and with increasing gestational age it also increases in volume. In the 3rd trimester, there is a slight decrease in fluid, because the uterus is already greatly stretched by the grown child.

Many years of studying intrauterine development have allowed doctors and scientists to calculate normal amounts of amniotic fluid specific for each period. It is not customary to measure them using standard liquid measures - milliliters, for example.

To assess their quantity, there is a special parameter - the amniotic fluid index. It can be determined in millimeters starting from the 16th week of gestation when undergoing an ultrasound scan.

IAH norms - table:

Since the amount of water in the amniotic sac is not constant, different dates one and the same expectant mother may experience oligohydramnios, but after a few weeks it is not detected. This natural phenomenon is called functional oligohydramnios. This is the most harmless of all types of this complication.

Usually, when a doctor pronounces “oligohydramnios,” a woman falls into a stupor. Expectant mothers should be reassured by the following official statistics from the Ministry of Health:

• oligohydramnios occurs in about 4% of all pregnancies;
• only 0.5-1.2% of such cases have pathological causes;
• all other women (and the vast majority) carry to term perfectly and give birth to healthy children, since their oligohydramnios was physiological.

Pathological oligohydramnios is considered to be a persistent insufficient amount of amniotic fluid, which can be recorded repeatedly at a variety of times, starting from the 16th week.

Classification

Oligohydramnios can be acute if it appears suddenly under the influence of negative factors, or it can develop gradually and almost imperceptibly, and then it will be classified as chronic.

With acute oligohydramnios, a pregnant woman’s body can respond to a viral disease, influenza or acute respiratory viral infection, from which the expectant mother was unable to protect herself during the period of bearing the baby. This disruption is usually temporary and does not mean that the baby has pathologies.

Chronic oligohydramnios is more dangerous. It usually develops due to problems that cannot be called quickly remediable - the mother's diabetes, obesity, as well as malformations of the child and his prolonged hypoxia. This disorder will not go away on its own; it definitely needs treatment. Also, the violation can be early if it was detected between 16 and 20 weeks and late if the problem was discovered only after 26 weeks.

In the case of early oligohydramnios, doctors’ forecasts are less optimistic, because the formation process has not yet been completed internal organs and baby systems.

Severe oligohydramnios in the early stages may be an indicator of gross genetic abnormalities in the baby, and therefore such a “find” on ultrasound requires detailed study using other diagnostic methods. In later stages, the disorder is often functional, completely natural, it can be easily corrected or goes away on its own.

Sometimes the development of such a disorder is influenced by the membranes, or rather their integrity:

• if they are not changed or injured, then doctors talk about primary oligohydramnios;
• if the shells are damaged and water leaks, we are talking about a secondary violation.

Primary oligohydramnios occurs in 80% of cases. Based on the quantitative indicator of deviations from the norms indicated in the table, moderate and severe oligohydramnios are distinguished.

Causes

The reasons for the reduction are so important for the baby amniotic fluid diverse. These may include malformations of the child, his diseases, pathologies of the placenta, as well as diseases of the expectant mother, both acute and chronic.

Some genetic, including chromosomal abnormalities that arose during the period of conception, during the formation of the genetic code and karyotype of the fetus, occur precisely against the background of a decrease in the amount of amniotic fluid.

In particular, the development of oligohydramnios is caused by such defects as abnormal development of the urethra and its valves, as well as abnormal narrowing of the baby’s urethra or its complete absence, joint (on both sides) narrowing of the ureters or anomalies in their structure.

Severe oligohydramnios is observed in pregnant women if the baby, due to an “error” of nature, completely lacks kidneys as such.

Polycystic kidney disease in babies (Potter's syndrome) is also a very obvious cause of pregnancy disruption. Among chromosomal abnormalities, oligohydramnios is most often accompanied by Down syndrome and Turner disease.

If everything is fine with the baby’s genetics, and this can be confirmed using other diagnostic methods, then doctors consider the likelihood of infection of the fetus. The most dangerous from the point of view of the risk of oligohydramnios are - cytomegalovirus infection and chlamydia. A lag in the amount of water from the norm often occurs with delayed fetal development.

The main maternal ailment that can lead to oligohydramnios is preeclampsia. In addition, a similar condition can be caused by venous insufficiency, a tendency to form blood clots, and diseases of the cardiovascular system.

Kidney ailments in the expectant mother have a detrimental effect on the amount of water, and diabetes. Dehydration can also cause a decrease in amniotic fluid, as can smoking, which some expectant mothers, even being in an “interesting situation,” cannot say goodbye to.

Placental pathologies lead to oligohydramnios - insufficiency, infarctions of the “children’s place”, any anomalies in its development that occurred during the formation of this temporary organ at the very initial stages.

Among other reasons that can lead to such an unpleasant complication of pregnancy are postmaturity, which causes natural aging of the placenta, injury to the membrane of the amniotic sac, the mother taking a large number of medications for a long time, as well as fetal death and multiple pregnancies.

Symptoms and signs

A woman practically cannot determine oligohydramnios on her own; this is a matter for specialists. Only a few signs may indirectly indicate the likelihood of a decrease in the amount of amniotic fluid.

Typically, women with oligohydramnios have smaller abdominal sizes than expected. It becomes possible to establish a violation thanks to measurements of the height of the uterus, which are carried out at each routine examination in the antenatal clinic.

When the expectant mother begins to feel the movements of her child, with oligohydramnios they can be quite painful for the woman.

You cannot remain silent about such sensations; if the symptom has not been diagnosed earlier, you should definitely report your suspicions to the doctor, who will prescribe all the necessary diagnostics in this case.

Diagnostics

The amniotic fluid index is determined by an ultrasound doctor. It measures the distance, free from the baby’s limbs and the umbilical cord, between the baby and the anterior abdominal wall, its inner surface. This measurement is called the vertical pocket.

If the measurement result after a comparative analysis with the tables shows that the amount of water is reduced, the degree of violation is revealed. With moderate oligohydramnios, the index is reduced by 10-15% compared to the above norm, and the vertical pocket, which with a normal amount of water is 5-8 cm, is reduced to a size of less than 5 cm.

A pronounced disorder is one in which the vertical pocket does not exceed 2 cm, and the amniotic fluid index deviates from the norm downwards by 15-20%. To imagine all of the above in more detail, we present a comparative table.

Violations of the amount of amniotic fluid:

If the ultrasound specialist indicates in the conclusion that the woman shows signs of moderate oligohydramnios, the obstetrician-gynecologist will definitely refer her for dopplerometry and expert ultrasound, in order to more accurately know the condition of the child, the placenta and blood flow in the uterine vessels.

When the ultrasound report indicates that a pregnant woman has severe oligohydramnios, she is hospitalized for a more thorough examination.

If the reason lies in congenital pathologies of the baby, it is recommended to terminate the pregnancy for medical reasons. Whether to agree or not is up to the pregnant woman to decide. If she refuses, the child is kept until birth and given the necessary medicinal support.

Possible consequences for the mother

A woman with oligohydramnios faces the risk of termination of pregnancy in the later stages, which is traumatic for both the psyche and physical health reproductive system. If the child dies, there will be no other option. After a long-term abortion, a woman may experience a nervous breakdown and develop secondary infertility.

A small amount of amniotic fluid aggravates the birth process itself. Weakness of labor forces often develops, and the woman faces a caesarean section. The postpartum period in such women is more difficult, complications are likely.

Pregnancy itself can give the expectant mother a lot of unpleasant sensations: the larger the child becomes, the more difficult it will be for the woman to withstand his movements.

The probability of miscarriage during pregnancy with oligohydramnios is high, and the risk of premature birth is even higher - it reaches 26%.

Possible consequences for the child

Children born after pregnancy with oligohydramnios have little weight and are weaker than their peers, even if the pregnancy is carried to term before the expected date of birth.

The most severe consequences of prolonged polyhydramnios include various fusions of the skin of the fetus and the membranes of the amniotic bladder. As a result of such adhesions, all the free space of the uterine cavity can be filled with cords. They can entangle even a baby.

Due to the pressure that the cords will exert on the fetal tissue, irreversible deformities are formed - babies have self-amputated or severely bent limbs, there are defects in the face and chest. The baby's appearance is completely disfigured. The frequency of such consequences is low, but this cannot be ruled out.

The likelihood of such an outcome increases if oligohydroamnion is diagnosed early, at 16-20 weeks, and persists throughout pregnancy.

During childbirth, the baby may face other troubles associated with a small amount of amniotic fluid - prolapse of the umbilical cord, premature disruption of the integrity of the amnion and, as a result, long-term anhydrous period, which can result in hypoxia and infection.

Many women mistakenly believe that oligohydramnios is the cause of the development of diseases such as Down syndrome, as well as other chromosomal abnormalities. The logical connection here is the opposite - with Down syndrome, oligohydramnios often develops, and not vice versa.

Almost always, prolonged oligohydramnios causes intrauterine growth retardation in the baby. In this case, the underdevelopment of the lungs with which mothers give birth to such babies is dangerous.

However, if help was provided to the baby correctly and in a timely manner, then the child quickly begins to gain weight and soon catches up with his peers in physical development. However, intellectually, the baby may develop late for a long time.

Cases where oligohydramnios is detected later are also dangerous from the point of view of the likelihood of developing complications. at 30 weeks of pregnancy, but only on condition that the pathological condition persists for 4-6 weeks or more.

Any negative consequences of oligohydramnios on a child’s health are characterized by a pattern - the earlier this condition occurs, the more severe the consequences can be.

Treatment

Therapy for oligohydramnios is always comprehensive. And it starts with establishing exact reason, which caused a pathological decrease in the amount of amniotic fluid.

First of all the version with chromosomal abnormalities is checked. To do this, the woman, depending on the period, is referred to one of the methods of invasive prenatal diagnosis.

If oligohydramnios is detected at 16 weeks, a chorionic villus biopsy can be performed. If the fact of oligohydramnios becomes known later, the woman may be referred for cordocentesis or amniocentesis.

These procedures will help obtain samples of amniotic fluid with particles of the baby's epithelium, and cord blood from the umbilical cord. An analysis will be carried out in the genetic laboratory that will allow us to speak with a high degree of accuracy about the presence or absence of Down syndrome, Cornelia de Lange syndrome and other anomalies in the baby that are associated with a violation of the number of chromosomes in the karyotype and cause oligohydramnios. Such studies are usually conducted for free.

Recently, it has become possible to do a non-invasive prenatal DNA test, which is still expensive. It is absolutely safe for the baby and is based on isolating the baby’s DNA from the venous blood of a pregnant woman. This test detects chromosomal abnormalities with a 99.9% probability and is an ideal alternative to invasive tests, which can be dangerous for both the pregnant woman and the fetus.

If the cause of oligohydramnios is confirmed due to chromosomal pathologies, termination of pregnancy is recommended.

If the additional examination does not show the presence of gross chromosomal abnormalities in the child, then expert-class ultrasound specialists will look for defects in physical development. To do this, they will carefully examine the baby’s urinary system - ureters, urethra, kidneys. Special attention will focus on the health of the placenta. To assess blood flow in the uterine vessels, ultrasound scanning is performed.

The attending physician will refer the woman for blood tests, which can confirm or deny the presence of infections, including sexually transmitted infections.

Be sure to donate blood for sugar and urine for protein content. The doctor monitors the blood pressure of the expectant mother to rule out gestosis as a cause of oligohydramnios.

If the cause is found, doctors decide how to treat the underlying disease; almost all of them, except for congenital malformations of the fetus and chromosomal pathologies, are treatable. At the same time, control over the condition of the fetus is enhanced.

Moderate oligohydramnios can be treated at home, in most cases hospitalization is not required, if the expectant mother follows all the doctor’s recommendations.

Severe oligohydramnios, if detected early, is also an indication for termination of pregnancy; none of the doctors will dare to make predictions about its outcome. With severe oligohydramnios, diagnosed after 26 weeks, the woman is hospitalized.

Drug treatment

An expectant mother with severe oligohydramnios is injected with vitamin solutions intramuscularly. In addition, she is given IV drips with drugs that improve uteroplacental blood flow. Typically used for this "Actovegin". Additionally, doctors recommend taking "Courantil", the dosage and frequency of taking this drug is determined by the doctor.

A pregnant woman may be prescribed broad-spectrum antibiotics to treat an infection if she has one. During the period of bearing a baby, it is often recommended for these purposes "Amoxiclav". To improve metabolic processes in a woman’s body, she may be recommended drugs such as "Hofitol", as well as multivitamin complexes designed and created specifically for pregnant women.

Simultaneously with taking medications in a hospital setting, the baby’s condition is checked daily or every other day. A woman undergoes CTG if her pregnancy is already over 28 weeks; the functionality of the placenta is monitored using ultrasound scanning; ultrasound scanning can be carried out at any time to assess the amount of water in dynamics.

Any alarming symptoms that may indicate a problem with the fetus can at any time become a decisive reason for doctors to perform a cesarean section ahead of schedule.

For moderate oligohydramnios, which, according to the doctor, is of physiological origin, the woman is prescribed "Curantil", "Actovegin" in tablets and multivitamin preparations, she will have to come for an appointment once a week, each appointment will be accompanied by a cardiotocographic study (CTG) until the doctor makes a diagnosis based on normal values ​​of the amniotic fluid index based on the results of an additional ultrasound.

A woman diagnosed with oligohydramnios should limit physical activity. This recommendation applies to both outpatient and inpatient treatment. Any heavy loads are strictly contraindicated.

Long walking and sports are undesirable during such a complicated pregnancy. Additionally, you will have to limit sex. Pregnant women who are overweight or obese are recommended to go on a special diet to prevent even further weight gain.

Nutrition for oligohydramnios should include a large amount of fruits and vegetables, proteins and fats should be balanced, and it is better to avoid fast carbohydrates (sweets and baked goods) altogether.

If there is swelling, you should definitely consult a doctor, together to develop a correct and sufficient drinking regime. For gestosis and hypertension, it is important to measure arterial blood pressure twice a day. If it increases significantly, a woman needs qualified medical care.

Traditional methods of treatment

Alternative medicine is ready to offer pregnant women with moderate oligohydramnios a lot of useful and pleasant to use recipes and products that, even if they do not increase the amount of water, can definitely satisfy the needs of the expectant mother with a deficiency of amniotic fluid for essential minerals and vitamins.

You shouldn’t even try to treat severe oligohydramnios with folk remedies. But with minor deviations from the norm, a woman may well take some advice if her doctor has nothing against it.

Figs, melon and grapes will help restore mineral needs for oligohydramnios. Zucchini and fresh tomatoes also help, according to reviews from expectant mothers.

Can become a real treasure trove, a natural “pharmacy” for a pregnant woman with a deficiency of amniotic fluid. chokeberry. A woman can take 50 grams of juice from it or about 100 grams of berries per day.

Another favorite remedy to help with oligohydramnios is strawberries. They are eaten fresh or homemade fruit juice is brewed with them to improve the normal functioning of the kidneys. If you are pregnant in the winter and there is nowhere to get strawberries, you can drink weak tea with strawberry jam. If this is not in stock, you can purchase it.

Prevention

Correct and responsible planning of the child will help to avoid oligohydramnios during pregnancy. A woman should be examined in advance by doctors of various specialties who can answer questions about her state of health and the presence or absence of chronic diseases.

Of course, there is no need to conduct a full medical examination, but a woman who dreams of a child is simply obliged to visit a cardiologist, therapist and nephrologist. Visits to these specialists will help you be sure that the heart, kidneys and general health will help the woman carry the baby without complications.

If the age of the expectant mother exceeds 35 years, it is worth consulting with a geneticist, because the likelihood of conceiving and giving birth to a child with Down or Patau syndrome increases in proportion to the mother’s age.

It would be correct to do tests for sexually transmitted and other infections before conception, and if something like this is discovered, treat them before the child is conceived.

You should quit smoking before conception, or at least as soon as you become aware of your pregnancy. Smoking, and this has been proven, very often acts as a provoking factor for oligohydramnios.

During pregnancy, a woman for preventive purposes it is important not to refuse to undergo mandatory screening tests in the first, second and third trimester, do not refuse an ultrasound scan and undergo certain tests recommended by the doctor.

Expectant mothers should protect themselves from viral infections, especially during periods of mass incidence of ARVI and influenza, in order to avoid the development of oligohydramnios after illness. To do this, you should refrain from visiting shopping centers and public transport during seasonal epidemics, observe the rules of personal hygiene.

If the doctor insists on hospitalization, you should not refuse it, even if the woman herself thinks that she feels great and she does not have time to stay in the hospital.

Amniotic fluid is necessary to ensure normal intrauterine development of the fetus. For the future baby, it is a comfortable physiological environment, an additional source of nutrition and oxygen, and also a protective barrier that protects him from numerous external threats. In addition, amniotic fluid plays an important role in the process of childbirth, forcing the dilation of the cervix, as it is capable of exerting a mechanical effect on it.

Therefore, a relative lack of water can lead to various violations fetal development and interfere with the normal course of pregnancy. Why is oligohydramnios dangerous? What are the different degrees of this condition, and what therapeutic method is most effective in this situation?

What is “moderate oligohydramnios”

Indicators of normal amniotic fluid volume vary depending on the specific stage of pregnancy. During the first 8 weeks this is approximately 5 ml. Next, the amount of fluid begins to increase, and by the end of pregnancy its total volume reaches an average of 1-1.5 liters. Immediately before birth, the water becomes smaller (their volume is approximately 600-700 ml).

The composition of amniotic fluid (from the word “amnion” - fetal sac) includes amino acids, vitamins, hormones, trace elements, some types of salts, enzymes, etc.

Amniotic fluid is formed due to the functioning of the epithelial layer of cells in the aqueous membrane of the amnion. They are constantly updated. At the extreme stages of pregnancy, this happens at least every 3 hours.

On average, per day the fetus has the ability to swallow 4 ml of amniotic fluid, and through the pores of the fetal sac, waste products enter the maternal excretory system. With a non-critical “shift” from normal levels of amniotic fluid volume (closer to the lower limit of normal), a pregnant woman is diagnosed with moderate oligohydramnios.

Causes

It happens that this condition is registered already in the initial stages of pregnancy. A similar diagnosis is made based on calculating the oligohydramnios index. In this case, the woman needs constant medical supervision and the use of certain methods of drug therapy.

The reasons for the formation of such a violation may be:

• persistent hypertension (increased total blood pressure);
• the presence in the body of a pregnant woman of any inflammatory process of an infectious nature;
• fetoplacental insufficiency;
• hypoxia (oxygen “starvation”) of the fetus;

• diseases of a pregnant woman associated with metabolic disorders;
• the presence of any pathologies in the fetus (underdevelopment of the excretory system will lead to a sharp decrease in the level of primary urine production, which leads to a reduction in the volume of amniotic fluid);
• post-term pregnancy - the placenta can be reversed and therefore no longer has the ability to provide the fetus with all the necessary substances, including producing a sufficient volume of amniotic fluid;
• multiple pregnancy - here there may be a disruption in the distribution of placental blood, which can also lead to water deficiency;
• violation of secretion in epithelial cells aqueous membrane of the amnion.

Types of oligohydramnios

Based on the duration of the course, there are two types of oligohydramnios: acute and chronic.

Chronic oligohydramnios has several levels of development. This condition requires long-term therapy. If qualified assistance is not provided on time, the disease will worsen., which will lead to serious consequences for both the expectant mother and the child.

Chronic deficiency of amniotic fluid can occur if a pregnant woman suffers from a systemic disease, such as diabetes.

To bring it all together possible risks to a minimum and apply appropriate therapy in a timely manner; in case of oligohydramnios, a woman needs to register with the hospital as soon as possible antenatal clinic and regularly undergo all necessary examinations.

The most common cause of acute oligohydramnios is an infectious disease. This form of pathology leaves fewer negative consequences for the baby’s health and does not require special treatment, since the situation usually stabilizes with the successful elimination of the disease that caused it.

In addition, oligohydramnios is classified depending on the functional activity of the cells of the aqueous membrane. Based on this principle, primary and secondary forms are distinguished. Primary oligohydramnios is characterized by the absence of any functional disorders in the membranes. With secondary oligohydramnios, damage to the structure of the amnion is observed, causing water to leak out.

Symptoms

Quite often, the clinical picture of moderate oligohydramnios does not have pronounced manifestations (therefore, this condition in some cases can be regarded as borderline with the norm). However, a pregnant woman should pay attention to some signs characteristic of this condition, if they occur. Among these symptoms:

• lower abdominal pain;
• painful tremors;
• weak and infrequent tremors;
• the size of the uterus does not correspond to the duration of pregnancy (detected by an obstetrician-gynecologist).

If any of these symptoms appear, even if they seem minor, you should immediately report them to your doctor so that he can prescribe a series of examinations that can help identify oligohydramnios.

Possible complications

Insufficient volume of amniotic fluid can become an impetus for the development of a number of complications, among which:

• Impaired blood flow in the umbilical cord. Because of this, the baby does not get enough oxygen and food. Persistent hypoxia can provoke the development of irreversible disorders in a child and even lead to his death.
• “Failure” in the process of circulation of amniotic fluid. Similar condition can lead to infection, and also significantly increases the likelihood of a traumatic birth.
• Flat amnion. This complication can provoke a weakening of labor in the first stage of labor.
• Placental abruption. Small fragments of the placenta are retained in the uterus, which increases the risk of bleeding.
• Fetal underdevelopment. If during the process of intrauterine development a child regularly did not receive the amount of nutrients and microelements he needed, then his body weight at birth will be less than normal.

Diagnostic methods

The main instrumental diagnostic methods used by the doctor to determine the volume of amniotic fluid are ultrasound and Doppler sonography. With their help, you can evaluate umbilical blood flow, how much the child is lagging behind in development, as well as the condition of the blood vessels of the expectant mother and fetus.

In addition, an obstetrician-gynecologist may additionally prescribe cardiotocography to study the functional capacity of the baby’s cardiovascular system. With established moderate oligohydramnios in the third trimester This study is carried out at 30, 34 and 36 weeks of pregnancy.

When registering, a woman must undergo screening for sexually transmitted infections.

Therapy

Correction of this condition should be carried out in several directions:

• prescribing medications that normalize metabolic processes in the placenta;
• drug therapy for the underlying disease.

If a pregnant woman suffers from any disease associated with metabolic processes, or is overweight, then most likely the specialist monitoring the pregnancy will recommend adhering to a special diet.

Moderate oligohydramnios usually does not require constant monitoring in a hospital setting, the future condition can be normalized on an outpatient basis.

In addition to drug therapy, with moderate oligohydramnios, the expectant mother must observe some restrictions regarding her physical activity. She should also make sure that her daily diet includes foods rich in vitamins and microelements.

The duration of pregnancy plays a largely determining role in drawing up a treatment plan. This pathology requires the most careful monitoring in the 2nd trimester. If oligohydramnios is diagnosed at 37 weeks, this may be an indication for a cesarean section.

Prevention

Currently, no effective methods have been developed to prevent the risk of developing oligohydramnios. But there are a number of recommendations, the exact implementation of which will help a pregnant woman reduce the risk of this pathology.

Plays an important role diet of the expectant mother. It must be rich in all the elements (vitamins, proteins, microelements and other valuable substances) necessary for the normal development of the fetus and ensuring the satisfactory condition of the pregnant woman.

It is very useful for the expectant mother and the health of her baby to follow a balanced regime of physiological stress and rest. Work should be moderate, since excessive overwork can have a detrimental effect on the health of the woman and her baby.

However, you should not go to extremes and completely deprive yourself of even minimal exercise, as this can lead to rapid weight gain, which can complicate the course of pregnancy.

One of the main factors determining the nature of pregnancy and the success of delivery is emotional background of a woman. The presence of stress and regular mental overload sharply increases the risk of developing any associated complications, including oligohydramnios. A pregnant woman needs to undergo all examinations prescribed by a doctor on time.

Use any additives or medications it is necessary only with the approval of a specialist, and not relying on incompetent reviews.

Conclusion

Moderate oligohydramnios occurs against the background of certain pathologies of intrauterine development of a child or diseases of a pregnant woman. Its distinguishing feature is the absence of pronounced symptoms. At timely therapy this deviation does not pose a great threat to the normal development of the fetus and the health of the expectant mother. The period at which moderate oligohydramnios was diagnosed is important, since at different periods of pregnancy such a disorder can have its consequences.

Oligohydramnios during pregnancy: causes, symptoms, treatment

What is oligohydramnios?

Oligohydramnios is somewhat less common than excess amniotic fluid. At the same time, oligohydramnios serves as a signal that there are some deviations in its course that are dangerous to the health of the fetus and interfere with its normal development. The composition of amniotic fluid is very diverse; it contains nutrients for the child, oxygen, vitamins, salts, hormones, and a number of other substances, without which normal intrauterine development child is impossible. At the same time, amniotic fluid is not only a source of nutrition for the fetus, but also its reliable protection from adverse factors and infections.

The amount of amniotic fluid varies depending on the duration of pregnancy and the needs of the fetus. Thus, in the third trimester of pregnancy, the normal amount of amniotic fluid ranges from 1000 to 1500 ml. If these indicators are lower, we can talk about oligohydramnios of varying degrees. There are cases where a pregnant woman had virtually no amniotic fluid at all. Depending on the severity, oligohydramnios can be moderate or severe. With moderate oligohydramnios, when the amount of amniotic fluid is slightly less than normal, a woman should adjust her diet, eat a variety of foods rich in vitamins and minerals, adhere to a gentle regimen, and regularly see a doctor to avoid worsening the condition.

Severe oligohydramnios requires more serious measures, the prescription of medications, and hospital treatment. With severe oligohydramnios, negative consequences can be observed such as deformation of the fetal skeletal system, abnormal development of its limbs, asphyxia, which leads to disruption of the central nervous system.

Symptoms of oligohydramnios

As a rule, with oligohydramnios, a woman does not feel any special symptoms or deviations in her health. Sometimes a pregnant woman may feel pain in the abdominal area, which worsens when the fetus moves. Thus, only a doctor can determine the presence of oligohydramnios. For example, if a doctor notices a lag in the height of the uterine fundus, its obvious discrepancy with the gestational age, as well as insufficient given period the size of the abdominal circumference, he can draw conclusions regarding the possibility of oligohydramnios. In order to completely confirm or refute this diagnosis, it is necessary to carry out ultrasonography, which will help determine the amount of amniotic fluid; if oligohydramnios occurs, then assess its severity and the condition of the fetus. If oligohydramnios is suspected, a woman is also prescribed a gynecological examination.

Causes of oligohydramnios

The reasons for insufficient amniotic fluid are not fully understood. As medical practice shows, the following reasons most often lead to oligohydramnios:

1. Insufficient development of the epithelium that covers the aqueous membrane, or reduced secretory function of this membrane itself.

2. Defects and anomalies in fetal development. Such defects include pathologies in the development of the child’s kidneys, hereditary anomalies in the development of the kidneys and face.

3. Increased water intake can lead to oligohydramnios during pregnancy. arterial pressure observed in a pregnant woman. Of course, during pregnancy, blood pressure increases in almost every woman, however, such deviations during the normal course of pregnancy are usually insignificant. If the pressure rises strongly, this may cause the development of oligohydramnios. It should be noted that the severity of oligohydramnios directly depends on pressure indicators. Also, in the case when the cause of oligohydramnios is hypertension, delays in the development of the fetus and its lag behind the norm in size are possible.

4. Oligohydramnios can be caused by various types bacterial infections suffered by a pregnant woman and not properly treated. At the same time, pathogenic microflora is detected during tests not only in the birth canal, but also in the amniotic fluid itself.

5. Oligohydramnios can occur when multiple pregnancy. This is due to the possible uneven distribution of blood flow in the common placenta, when one of the babies receives more nutrients and oxygen, and the other less.

6. Often, when pregnancy is carried beyond term, oligohydramnios develops. This is due to the fact that the placenta, which has served its intended purpose, begins to age and peel off, and is not able to fully perform its functions. In this case, doctors raise the question of artificial induction of labor.

7. Oligohydramnios can develop against the background of metabolic disorders in a pregnant woman, for example, with obesity.

Treatment of oligohydramnios

In order to select the most effective methods treatment of oligohydramnios, the doctor must establish the cause that caused the insufficient amount of amniotic fluid, the severity of the oligohydramnios. To do this, the pregnant woman must undergo examinations such as:

1. Ultrasound, Doppler sonography, during which the amount of amniotic fluid is determined. The degree of developmental delay of the fetus, the quality of blood flow in the umbilical cord, the woman’s uterine arteries, as well as in the fetal cerebral artery.

2. Tests and smears for sexually transmitted diseases and bacteria.

3. CTG of the fetus, which allows you to determine the condition and well-being of the fetus.

Treatment methods may vary. For example, if a woman has metabolic disorders or obesity, in addition to taking medications that normalize the activity of the placenta, it is recommended to adhere to a diet determined by the doctor. Most often, for oligohydramnios, complex treatment is prescribed, which includes taking drugs to improve metabolism in the placenta, vitamins, and medications intended to treat the underlying disease, which was the cause of oligohydramnios. Treatment can be carried out on an outpatient basis (with moderate oligohydramnios). In this case, a woman should limit her physical activity, adhere to a gentle regimen, avoid heavy physical activity, take medications prescribed by a doctor, and regularly attend antenatal clinics. If oligohydramnios is severe and is associated with increased uterine tone, the woman will have to go to the hospital.

In case of oligohydramnios, the doctor may prescribe a weekly ultrasound examination, Doppler ultrasound, which must be performed every three days, and an extraordinary fetal CTG. All these measures are necessary in order to control the pathology, prevent its development, and in some cases, take the necessary measures in a timely manner.

If oligohydramnios is severe and threatens the health of the fetus, the doctor may decide on early delivery using the caesarean section, if, of course, the timing of pregnancy allows it.

The effect of oligohydramnios on a woman’s condition

Oligohydramnios is a pathological condition that occurs during pregnancy and has an extremely negative impact on its course. A woman may experience painful sensations that intensify at those moments when the fetus begins to actively move. In addition, oligohydramnios can lead to much more dire consequences, for example, termination of pregnancy. Oligohydramnios, moderate or severe, significantly complicates the course of labor. This manifests itself, first of all, in the weakness of labor, because the fetal bladder, small in size, is not able to have a sufficient impact on the speed of dilatation of the cervix. In this case, the use of drugs that stimulate contractions may be necessary.

The effect of oligohydramnios on the condition of the fetus

Amniotic fluid is the natural habitat for the fetus. Insufficiency of amniotic fluid can have a very negative impact on its condition and development. Of course, the outcome of pregnancy can be favorable; many women who experienced oligohydramnios during pregnancy gave birth to completely healthy children, albeit with a slight delay in height and weight. However, there are other situations where oligohydramnios has a very negative impact on the child's health. For example, with oligohydramnios, the walls of the uterus are located close to the surface of the fetus's body, thus the child does not have enough space necessary for normal development. As a result, the fetus may experience deviations in the development of the skeletal system and limbs. The child, to one degree or another, begins to lag behind in height and weight, his skin becomes dry, covered with numerous wrinkles.

Pathologies in fetal development can be observed as with moderate oligohydramnios, although the degree of such hypotrophy is usually milder, there is a greater chance of birth healthy baby and when severe, when the fetus has obvious developmental delays, hypoxia, disturbances in brain and nervous activity, decreased tone of the limbs, and lethargy. Children born to mothers who experienced oligohydramnios during pregnancy subsequently, as a rule, often get sick and are more excitable.

Prevention of oligohydramnios during pregnancy

Unfortunately, there are no preventive measures that can guarantee protection against oligohydramnios. However, there are still a number of rules that a pregnant woman must follow at the very beginning of this period. For example, a pregnant woman should not lift heavy objects, as excessive exercise stress may lead to the development of oligohydramnios. But this does not mean that you need to completely abandon the movement. Slow walks in the fresh air are good for women in an interesting position. It is necessary to carefully consider your diet; it is best to eat meals in small portions, 5 times a day. It is important to undergo all examinations and tests in a timely manner, and if a problem is identified that can lead to oligohydramnios, begin the treatment prescribed by your doctor as soon as possible.

Naturally, you need to periodically come for examination to a doctor - a gynecologist who is managing the pregnancy, and strictly follow all his instructions. Conclusion: It is worth noting that oligohydramnios is far from the worst pathology that can be observed in a pregnant woman. Therefore, the risk that the baby could suffer some very serious injuries as a result of this is not so great. The main thing is to promptly identify oligohydramnios and take measures to eliminate it. In addition, modern medical equipment and medications make it possible to carry a baby to term and give birth to a healthy child in most problematic cases. Therefore, under no circumstances should you panic, be nervous or fall into despair, otherwise nothing, even state-of-the-art drugs and equipment, will help.

What is polyhydramnios?

Expecting a child is the most wonderful period in the life of every woman. However, even these bright moments can be overshadowed by such troubles as, for example, polyhydramnios. Ideally, nature creates optimal conditions for the correct and complete development of the fetus in the womb. The fetus is surrounded by amniotic fluid, which not only creates the necessary conditions for the development of the baby, but also provides it with oxygen and nutrients. However, numerous negative factors, such as poor ecology, poor nutrition, and the presence of infectious diseases in a pregnant woman, can provoke deviations in the formation of the baby’s development environment. Such deviations include polyhydramnios during pregnancy.

Polyhydramnios is an excess volume of amniotic fluid surrounding the fetus. There are certain norms for the amount of amniotic fluid. So, at the tenth week their amount should be about 30 ml, at fourteen weeks of pregnancy - 100 ml, and during the last trimester this amount can range from 1000 to 1500 ml. If the amount of amniotic fluid exceeds the specified norms, we can talk about the presence of polyhydramnios. Modern medicine knows several types of polyhydramnios: acute and chronic polyhydramnios, and it also varies depending on the severity. For example, if the excess of amniotic fluid is insignificant, we are talking about a mild degree of polyhydramnios, but if the amount of water greatly exceeds the norm, then the doctor states severe polyhydramnios.

Symptoms of polyhydramnios during pregnancy

The symptoms that a pregnant woman may experience with polyhydramnios vary. For example, acute polyhydramnios, which, by the way, does not develop very often, mainly on early stages pregnancy, and is characterized by a rapid increase in the amount of amniotic fluid, a feeling of heaviness in the abdomen, and a sharp increase in its size. In this case, the pregnant woman may feel acute pain in the lower back and perineal area. Often, a woman’s blood pressure increases, and the fetal heartbeat is difficult to hear.

Chronic polyhydramnios most often manifests its symptoms in the third trimester of pregnancy. However, these symptoms are not as noticeable as in the case of acute polyhydramnios. With such polyhydramnios, the size of the pregnant woman’s abdomen increases gradually; most often, the woman adapts to such changes without attaching much importance to them. Meanwhile, chronic polyhydramnios is a sign of any pathologies during pregnancy. Such pathologies may include bacterial or infectious diseases suffered by the pregnant woman, kidney diseases, cardiovascular diseases, and diabetes mellitus.

Diagnostics

Diagnosis of polyhydramnios during pregnancy is carried out on the basis of the woman’s complaints; to confirm the diagnosis, the doctor prescribes an additional ultrasound examination, and also determines the so-called “amniotic index”. If its levels exceed the norm, the doctor diagnoses “polyhydramnios during pregnancy.”

Reasons for the development of polyhydramnios during pregnancy

In general, the reasons that can lead to the development of polyhydramnios in a pregnant woman have not been sufficiently studied to date. Although qualified doctors conclude that the following factors can lead to the appearance of excess amniotic fluid:

1. The presence of bacterial or infectious diseases that the woman suffered during pregnancy or immediately before conception.
2. Also, diseases such as diabetes mellitus and pyelonephritis can lead to the development of polyhydramnios, when metabolic disorders and fluid exchange in the body are observed.
3. Cardiovascular diseases that cause disturbances in the circulatory system can contribute to the development of polyhydramnios.
4. Excessive amount of amniotic fluid can be observed in the so-called Rh conflict, when the mother’s Rh factor is negative and the father’s is positive.
5. Multiple pregnancy can also cause polyhydramnios. In this case, phenomena such as an excessive amount of water in one fetus and insufficient water in another may be observed.
6. Polyhydramnios can also occur with pathologies in fetal development.

Depending on the reasons for polyhydramnios during pregnancy, treatment for this abnormality is prescribed. Naturally, for successful treatment it is necessary to identify the cause of the development of polyhydramnios and eliminate it, if, of course, this is possible.

Treatment of polyhydramnios during pregnancy

As mentioned earlier, in order for the treatment of polyhydramnios to be as effective as possible, it is necessary to identify the cause of this deviation during pregnancy. To do this, the doctor prescribes a number of necessary examinations. This:

1. Ultrasound examination and Dopplerography (a method that allows you to examine the vessels, fetus, uterus and umbilical cord), during which the condition of the uterus and fetus and the state of blood flow in the placenta are determined.
2. CTG (cardiotocography) of the fetus, which allows you to assess its general condition.
3. A pregnant woman must take a blood test, which allows diagnosing the presence of intrauterine infection.
4. Blood test, as well as a smear for sexually transmitted infections, for example, chlamydia, mycoplasma, ureaplasma.
5. If a woman has a negative Rh factor, then she will also have to take a blood test for antibodies.

Depending on the reasons that caused polyhydramnios, as well as on the severity of the pathology, appropriate treatment is used. For example, for mild polyhydramnios and moderate polyhydramnios, prescribe drug treatment, which can be carried out both on an outpatient basis (for mild polyhydramnios) and in a hospital (for moderate polyhydramnios). In this case, premature delivery is not required, that is, the pregnancy proceeds until its natural completion against the background of prescribed continuous treatment. In this case, the woman is prescribed antibiotics, vitamins, and diuretics (diuretics). In addition, during pregnancy from twenty-four to thirty-eight weeks, the pregnant woman is prescribed indomethacin. If, despite Taken measures, polyhydramnios develops, becomes severe, and at the same time signs of intrauterine suffering of the child are observed, the doctor, as a rule, decides on early delivery.

For this purpose, special drugs are used - stimulants, which act in a special way, giving a signal for the onset of labor. When artificially inducing labor, the following rules must be observed. Firstly, the membranes surrounding the baby must be opened from the side, slightly above the location of the internal os, and not in the center. Secondly, amniotic fluid should be released gradually to avoid asphyxia (suffocation) of the fetus. In addition, it is necessary to take appropriate measures to help prevent the umbilical cord loop or the baby’s limb from falling out. And finally, medications that stimulate labor should be used no earlier than two hours after the rupture of amniotic fluid.

If in the early stages of pregnancy, when the question of early delivery is unacceptable, the woman is often prescribed the release of amniotic fluid. The procedure should be carried out with utmost care to prevent the umbilical cord loop from falling out.

The effect of polyhydramnios on the condition of a pregnant woman

In addition to the feeling of discomfort and pain that can be observed with polyhydramnios, this pathology can significantly complicate the process of childbirth, causing such negative phenomena as weak contractions, premature separation of the placenta, which previously developed and functioned quite normally, excessive bleeding, which is associated with excessive stretching uterus during pregnancy. In addition, recovery processes after polyhydramnios pregnancy and childbirth occur with some complications.

The effect of polyhydramnios on the fetus

Polyhydramnios during pregnancy can harm not only the mother, but also negatively affects the condition of the fetus. The organ that provides the intrauterine water environment for the fetus is a very important element that plays a responsible role in protecting the fetus from negative influences, infections, and provides nutrition to the fetus and its respiration. Consequently, disturbances in the activity of this organ, such as polyhydramnios, can change the the worst side environment of the fetus, which leads to its intrauterine suffering.

Polyhydramnios is common cause various types of defects in the development of the fetus, all kinds of pathologies, up to its perinatal death. In addition, polyhydramnios complicates problems, which, as is known, are a difficult ordeal not only for the mother, but also for the child. As a result of the weakening of labor, which is often observed with polyhydramnios, the child may experience asphyxia, which negatively affects the general condition of the baby and the activity of his central nervous system.

Prevention of polyhydramnios

Polyhydramnios during pregnancy is not a harmless phenomenon, even if we are talking about a mild degree of pathology. The fact is that polyhydramnios signals any disturbances during pregnancy, the presence of certain diseases that can harm the health of the woman and child. In this regard, it is necessary to think about preventive measures that can prevent the development of polyhydramnios. Such measures, first of all, include the need for appropriate examinations that will confirm or refute the presence of diseases, Rh conflict, and other reasons that can lead to polyhydramnios. You should adjust your diet and clearly determine the amount of fluid consumed.

From the very beginning of the child’s waiting period, you should be in the fresh air more often. Walking is very useful. And, most importantly, you must strictly follow all the prescriptions of the doctor who is managing your pregnancy, take all the vitamins and medications that he prescribes for you, undergo an ultrasound procedure on time, which can show the development of polyhydramnios at the initial stage, when the treatment of this pathology will be as simple as possible and effective.

Update: October 2018

Amniotic fluid is the fluid that surrounds the fetus throughout pregnancy. It contains minerals, urea, glucose, proteins, fats and carbohydrates. Among the components of water there are a large number of hormones, immune factors, and bactericidal substances. As the gestation period increases, the water accumulates hairs and skin scales of the fetus.

Why amniotic fluid is needed?

Amniotic fluid plays a very important role in maintaining the life of a small person. In fact, this is the only habitat of the fetus that performs the following tasks:

• prevents mechanical damage to the fetus
• creates a favorable space so that the fetus can move unhindered
• protects the umbilical cord from compression during childbirth
• actively participates in fetal metabolism
• stimulates the development of the lungs (due to the movement of fluid in them in two directions)
• has antimicrobial and properties

How is amniotic fluid formed?

Amniotic fluid accompanies the fetus throughout almost the entire pregnancy. In the first trimester, when the embryo's organs are just forming, some of the mother's blood penetrates the fetal membranes, forming a small level of fluid. This level can be seen as early as 3 weeks of pregnancy. There is an opinion that the baby’s blood plasma can also “leak” through his skin in the shortest possible time.

In the second trimester, the main source of amniotic fluid is the fetus itself. Urine and fluid secreted by the lungs enter the space surrounding it.

From there it can be swallowed by the fetus, and part of it is absorbed directly into the mother’s blood. For example, during full-term pregnancy, the fetal lungs secrete up to 400 ml of fluid per day, the volume of urine per day can reach 1 liter.

Ingestion of water begins from 18-20 weeks of pregnancy, by 40 weeks the fetus swallows up to 500 ml of water per day (see). Within 3 hours, the amniotic fluid is completely renewed.

The total amount of amniotic fluid depends on the balance of these two processes (formation and excretion of fluid).

What is oligohydramnios?

Oligohydramnios is a decrease in the level of amniotic fluid to 0.3-0.5 l during full-term pregnancy. About 0.3–5.5% of all pregnancies are accompanied by oligohydramnios of varying severity.

Causes of oligohydramnios

The main cause of oligohydramnios during pregnancy is considered to be impaired functioning of the fetal kidneys. But there are many more factors that affect the balance of amniotic fluid:

• Fetal malformations
  • posterior urethral valves
  • absent or narrowed urethra
  • bilateral obstruction of the ureters and other parts of the urinary tract
  • undercut belly syndrome
  • absence of two kidneys
  • bilateral cystic renal dysplasia
  • polycystic kidney disease (infantile form)
  • cloaca abnormalities

• Fetal chromosomal abnormalities
• Disorders of the placenta (placental development abnormalities)
• Post-term pregnancy
• Antenatal fetal death
• Squeezed twin syndrome in multiple pregnancies
• Oligohydramnios caused by the use of prostaglandin synthetase inhibitors
• Oligohydramnios due to prenatal water leakage
• Causeless (idiopathic) oligohydramnios

Absence of both kidneys

The malformation, more common in boys, is characterized by the complete absence of both kidneys and severe oligohydramnios. This condition is lethal, that is, the fetus dies in utero or immediately after birth. The causes of the pathology are also considered to be chromosomal abnormalities and exposure to unfavorable factors (maternal diabetes, smoking and cocaine use, rubella virus infection).

When performing an ultrasound, the doctor notes a low level of amniotic fluid, the absence of a shadow of the kidneys and bladder. It is important to note that if the bladder is visible, then the fetus still has at least one kidney. And with unilateral agenesis (absence of a kidney), the condition of the fetus usually does not suffer, the quality of life of such a child is practically no different from other children.

Infantile form of polycystic kidney disease

A hereditary disease, the main symptom of which is huge kidneys with cystic deformation (in the form of large cavities). The disease is usually detected in the second half of pregnancy using ultrasound; an additional sign is severe oligohydramnios. The prognosis of the disease is quite poor; most children do not survive the first year. If a pathology is detected, it is necessary to undergo full karyotyping (determining the number and shape of chromosomes), since the risk of recurrence of polycystic kidney disease in future children is 1:4.

Posterior urethral valve syndrome

Pathology of male fetuses, in which valves form in the urethra. These growths interfere with the flow of urine from the bladder. Over time it stretches. As the disease progresses, the kidneys also enlarge. Therefore, ultrasound examinations of such babies reveal large kidneys, a distended bladder, and oligohydramnios. The prognosis depends on the onset of the disease and the degree of development of the lungs (very often they are underdeveloped).

Prune-belly syndrome

A rather rare congenital malformation of a child, combining three main features:

• absence or underdevelopment of the muscles of the anterior abdominal wall
• disorder of the structure of the urinary system in the form of a large bladder
• undescended testicles into the scrotum

In the case of a severe form of the syndrome, other anomalies may be added to these signs: dilation of the ureters, renal dysplasia and dilation of the renal pelvis. Sometimes this syndrome is combined with Potter's syndrome, when the child's kidneys are affected due to blockage of the urinary tract, the lungs do not develop, and a state of oligohydramnios occurs.

The syndrome is diagnosed already at the end of the second trimester, when an ultrasound reveals a huge fetal bladder. The prognosis of this disease is unfavorable, especially if oligohydramnios develops (in this case, termination of pregnancy is suggested). If a mild form is diagnosed, then observation and surgical intrauterine treatment are possible, although in this case the child’s chances of surviving the first year are very low.

Abnormalities of the cloaca

Anomalies of the cloaca are a rare combination of defects of the genitourinary system and the digestive tract of the fetus. Violations occur at the stage when these two systems are still combined into one.

Ultrasound reveals fluid and cysts in the child’s abdomen, absence or abnormal development of kidneys, and defects of the duodenum. Often the bladder and bowels are located outside the abdomen and are not covered by skin. With such pathologies, screening may indicate an increased level of AFP.

Often the pathology leads to the death of the child, but modern surgical methods make the chances of life for such babies quite high.

General features of malformations of the fetal urinary system:

• Most of these defects are accompanied by a reduced amount of amniotic fluid (due to the small volume of urine excreted)
• Severe oligohydramnios in pregnant women or anhydramnios (complete absence of water) are an unfavorable prognostic sign. In such cases, underdevelopment of the lungs is often observed - the main cause of death in newborns with such defects.
• Some defects can be treated surgically (bypass surgery) during pregnancy.
• There is an isolated enlargement of the kidneys, not accompanied by oligohydramnios, which goes away on its own during pregnancy.

Fetal chromosomal abnormalities

Most chromosomal diseases occur with polyhydramnios or a normal amount of water. In some cases (if the syndrome is associated with disorders in the urinary system), there may be a decrease in the level of amniotic fluid. The main diagnostic value is the second trimester and other ultrasound signs of chromosomal pathologies.

Intrauterine infections

In 30-40% of cases of severe oligohydramnios, infection of the membranes occurs. When transmitting infection from mother to fetus, the placenta and fetal membranes serve as an intermediary. Their inflammatory changes lead to placental insufficiency, decreased water levels and delayed development of the child. A complete absence of water is often observed during infection in the 1st trimester, resulting in congenital malformations of the fetus.

Fetoplacental insufficiency

Insufficient blood supply to the fetus by the placenta can occur for many reasons:

• genetic disorders of the placental bed
• infections
• gestosis
• diabetes mellitus and other chronic maternal diseases
• impaired ovarian function and many other factors

But the result is always the same: gradual (and sometimes sudden) oxygen starvation of the fetus. The most sensitive organ to hypoxia is the brain. Nature has invented a way to protect it by redistributing blood throughout the fetal vessels. As a result, other organs begin to receive less oxygen. These include the kidneys and lungs, which are directly responsible for the amount of amniotic fluid. Therefore, with placental insufficiency, oligohydramnios is a common occurrence.

Post-term pregnancy

The exact causes of oligohydramnios during post-term pregnancy are still unclear. Possible reason is the inability of the maternal body to satisfy the needs of an overripe fetus, which leads to fetoplacental insufficiency and, as a consequence, oligohydramnios.

Antenatal fetal death

Intrauterine death of a child is almost always accompanied by oligohydramnios. Firstly, acute placental insufficiency most often leads to death. Secondly, immediately after the death of the fetus, its kidneys and lungs stop producing amniotic fluid. Therefore, the decrease in the level of amniotic fluid can be very sharp, and the volume of the abdomen can decrease significantly.

Squeezed twin syndrome

In case of multiple pregnancy with twins, that is, as a result of fertilization of one egg, which subsequently splits, the number of complications is quite high. One of the most dangerous and common pathologies is fetafetal blood transfusion syndrome.

Almost 70% of identical twins share a placenta, that is, they are monochorionic monozygotic twins. It often happens that additional vessels are formed in the thickness of this placenta, connecting the twins. If at the same time the part of the placenta that supplies blood to one child (donor) begins to work worse, then most of the blood goes to the second twin (recipient). As a result, the recipient begins to produce more urine and becomes polyhydramnios. And the donor does not receive enough blood and oxygen, begins to lag in growth and develops oligohydramnios.

Without treatment, this pathology leads first to the death of the donor from oxygen starvation, and then to the recipient from severe swelling and intoxication. But modern methods can significantly reduce the mortality and morbidity of such twins:

• coagulation of additional vessels using laser
• Caesarean section as soon as possible after the death of the donor fetus (to save the life of the recipient fetus)
• in the short term, if the donor dies, the umbilical cord is closed (so that decay products and hormones do not reach the living fetus)

Iatrogenic oligohydramnios (caused by indomethacin)

Urine production by the fetus, and therefore the level of amniotic fluid, is controlled by many hormones and substances. These substances include prostaglandins, which regulate the diameter of the renal arteries. Drugs that suppress the synthesis of prostaglandins reduce renal blood flow and the amount of urine excreted by the child, which threatens the kidneys.

Indomethacin is a common drug with this effect, used to reduce the amount of amniotic fluid and prolong pregnancy. It must be used with extreme caution, as it can lead to fetal renal failure.

Leakage of amniotic fluid

Classic, followed by rupture of amniotic fluid. Often the membranes rupture before contractions. In a full-term pregnancy, labor begins after this, and its course differs little from the classic version. Completely different outcomes and prognosis occur if the membranes rupture before 36 weeks of pregnancy.

Causes of premature rupture of membranes

• incompetence of the cervix (isthmic-cervical insufficiency)
• membrane infection
• polyhydramnios
• abnormal fetal position and narrow pelvis
• medical procedures (amniocentesis, cordocentesis and others)

If the membranes rupture from below, then more often a complete rupture of water and subsequent birth occurs. If the gap is located from above, then water can leak gradually, practically without reducing the overall level of amniotic fluid. Therefore, the combination of even moderate oligohydramnios with suspicious liquid discharge from the vagina can be dangerous for the health of the mother and child; it is advisable to conduct additional research. Using test strips, you can detect amniotic fluid in the vagina and prescribe treatment. Depending on the duration of pregnancy, the condition of the fetus and mother, blood and urine tests, pregnancy extension or labor induction will be carried out.

Idiopathic oligohydramnios

Oligohydramnios, not accompanied by any of the above pathologies, is considered idiopathic, that is, causeless. Most often, the amniotic index is slightly reduced, and the condition of the mother and fetus is stable. As the period increases, the amount of water may return to normal, or it may remain small until birth, without affecting the baby’s health.

Symptoms of oligohydramnios

• the volume of the abdomen and the height of the uterine fundus lag behind the timing of pregnancy
• low fetal motor activity
• liquid vaginal discharge (due to rupture of membranes)

At each visit to the antenatal clinic, the pregnant woman’s abdominal volume is measured, which can indirectly reflect the amount of water. By the end of full-term pregnancy, it reaches 90-100 cm, but the value can vary if the woman is obese.

The main way to diagnose oligohydramnios is to determine the amniotic index using ultrasound.

How is the amount of amniotic fluid determined by ultrasound?

The main way to determine the level of amniotic fluid is to conduct an ultrasound examination. There are several techniques that allow you to estimate the volume of amniotic fluid with great accuracy.

• Measuring a vertical pocket

If the largest of the pockets in two planes does not exceed 1 cm, then a diagnosis of oligohydramnios can be made.

• Determination of amniotic fluid index

During this method, the entire cavity of the pregnant uterus is divided into 4 parts using two perpendicular lines passing through the navel. The maximum diameter of the liquid volume is then measured in each quadrant. By summing the data obtained in all quadrants, the amniotic fluid index is obtained.

To evaluate the results for each stage of pregnancy, special centile tables have been created, according to which doctors write a conclusion. If the index value is less than the 5th percentile, then a diagnosis of oligohydramnios can be made. Although oligohydramnios has practical significance only when the index is less than 2.5 percentile.

If you need to assess the level of amniotic fluid in the first half of pregnancy, then the uterus is divided into two quadrants with a vertical line.

Why is oligohydramnios dangerous during pregnancy?

• Appearance amniotic cords. If the amount of amniotic fluid is sharply reduced, adhesions may occur between the fetal skin and the amniotic membrane. They can entangle or pull parts of the fetus, which leads to deformation or even amputation of limbs.
• Impaired labor (due to a flat membrane). Contractions may be too weak and irregular.
• Compression of the umbilical cord during childbirth, up to acute hypoxia and fetal death.
• Disturbed position of the fetus in the uterus.

How to treat oligohydramnios?

The main principle of treating oligohydramnios during pregnancy is pathogenetic. This means that a decrease in the level of amniotic fluid in itself cannot be cured; the cause of this condition must be found. To do this, ultrasound is connected to a gynecological examination, monitoring of fetal heartbeats, genetic screenings, analyses.

If there are no additional signs other than oligohydramnios, then nothing needs to be treated. Monitoring the condition of mother and child is required. There is information that mothers may experience oligohydramnios. Some pregnant women with edema begin to arrange “fasting” days with limited fluid intake, which is extremely undesirable. Adequate fluids per day are necessary to maintain balance in the body.

If additional signs of trouble are detected, the primary disease must be treated:

• For congenital fetal defects– surgical treatment (if appropriate) or termination of pregnancy. A wait-and-see approach is possible.
• For chromosomal abnormalities– assessment of the child’s viability, after which – termination of pregnancy or expectant management
• For intrauterine infection– antiviral or antibacterial treatment (if necessary), monitoring the child’s condition. Before treating such diseases, you need to carry out all the necessary tests.
• For placental insufficiency– treatment with vascular drugs up to 20 weeks (Curantil), after 20 weeks – expectant management. If fetal development is severely delayed, the pregnant woman should give birth as early as possible (preferably after 33 weeks)
• In post-term pregnancy– induction of labor or expectant management (if the fetus is in normal condition)
• For complications of multiple pregnancy– treatment by shunting the blood vessels of the placenta, pumping out excess amniotic fluid from the recipient fetus. If the donor fetus dies, they usually try to deliver the pregnant woman as early as possible to preserve the life of the recipient fetus.
• When fruit membranes rupture– induction of labor or expectant management. The main task is to prevent infection of the fetus and allow the lungs to develop (with the help of hormone therapy).

How is childbirth conducted with severe oligohydramnios?

If an ultrasound reveals significant oligohydramnios, then doctors perform an early opening of the amniotic sac. The fact is that with a small volume of amniotic fluid, the bubble takes on a flat shape. As a result, it not only does not stimulate labor, but can even disrupt it. Therefore, it is better to open such a fetal bladder.

If oligohydramnios is extremely severe, then, if indicated, a caesarean section may be used.

Prevention of oligohydramnios

You can reduce the risks of oligohydramnios (but not make them zero) by properly preparing for pregnancy and following all doctor’s recommendations:

• Take 400 mcg of folate per day
• Get tested for HIV, syphilis and TORCH complex
• If a woman did not have chickenpox or rubella as a child, get vaccinated against rubella and chickenpox before pregnancy.
• To refuse from bad habits
• Control diabetes, hypertension and other chronic diseases
• Avoid taking medications without consulting a doctor during pregnancy

This is a decrease in the amount of amniotic fluid to 500 ml or less.

Causes of oligohydramnios during pregnancy

The reasons for this violation are not well understood. It is believed that oligohydramnios is associated with insufficient formation of amniotic fluid by the membranes or with their increased absorption by the placenta or membranes. Often, oligohydramnios is associated with malformations of the fetal kidneys, a form of their complete absence, and narrowing of the ureters.

Also of some importance is the disruption of blood flow in the placenta-fetus system.

Oligohydramnios negatively affects the course of pregnancy and fetal development. A small amount of water restricts the movements of the fetus, the forced position bends the spine, torticollis or clubfoot and other skeletal deformities are formed. With a small amount of water, the fetal skin touches the fetal membranes, which can form threads (cords) of fusion of areas of the fetal body with the fetal membranes. Such cords, during fetal movements, can lead to entanglement in the umbilical cord, squeeze fingers and limbs, sometimes even to the point of amputation, and cause circulatory disturbances in the fetus when the umbilical cord vessels are compressed.

The diagnosis is made by ultrasound, in dynamics. A pregnant woman with oligohydramnios is hospitalized in the maternity hospital, where treatment is carried out aimed at improving blood flow in the placenta and improving its nutritional function. Often, oligohydramnios is complicated by premature birth and placental abruption.

If oligohydramnios is diagnosed in combination with fetal malformations, then the pregnancy is terminated for medical reasons. If fetal growth is delayed, the outcome of pregnancy becomes problematic. In the third trimester, pregnancy is prolonged to 37 weeks and early delivery is carried out with careful monitoring of the fetal condition.

Severe oligohydramnios is characterized by a decrease in their quantity to 100 ml or less (in severe cases there may even be several milliliters of fluid in the amniotic space).

The reasons for the development of oligohydramnios are diverse, although, as with polyhydramnios, reliable causes have not been precisely established and have been little studied. Most often, this pathology is formed due to insufficient development of the amniotic epithelium (inner vesical membrane) or a decrease in its secretory (excretory) function. It is believed that a certain role in the occurrence belongs to the increased ability of the amnion (fetal bladder) to resorption (reabsorption) of amniotic fluid (scientific literature describes cases of complete disappearance of amniotic fluid, the amount of which was normal at the beginning of pregnancy). In itself, a decrease in water volume does not have pronounced detrimental consequences in the case when it does not last long and then is gradually restored to the proper level. However, along with a reduced amount of water, fetal growth retardation syndrome is more common. This is due to the fact that in a hypotrophic (low-weight) fetus, the normal functioning of the kidneys is naturally disrupted, and a decrease in hourly diuresis gradually leads to a decrease in the volume of amniotic fluid. Oligohydramnios is quite common in cases of development of identical twins, which is explained by the uneven distribution of blood circulating in the common placental apparatus between the two twins. These reasons are put forward as the most often assumed, however, along with them, the cause of oligohydramnios can be associated with various kinds of extragenital (outside the reproductive system) pathology of the mother (cardiovascular failure, disorders of the kidneys and liver).

When this type of pathology appears, in most cases complications of pregnancy and labor occur, which ends in spontaneous miscarriage and premature birth.

The presence of oligohydramnios during pregnancy adversely affects the growth and development of the fetus, therefore this condition is classified as a painful condition and requires a full examination and treatment. Developmental disorders are a consequence of limited motor activity of the fetus due to insufficiency of amniotic fluid. Against this background, congenital clubfoot most often occurs, in some cases curvature of the spine and deformation of other skeletal bones. Often, with oligohydramnios, adhesions form between skin child and amnion. As the fetus further increases in size, they become elongated, and after delivery they take on the appearance of cords and threads. However, the possibility of the development of such strands against the background of an anomaly in the development of the ectoderm cannot be excluded. These formations sometimes cover the child’s torso and limbs, the umbilical cord, which causes disfigurement or even amputation of various parts of the body. Fetal death is possible as a result of compression of the umbilical cord. Fetal developmental defects are possible with oligohydramnios.

Primary oligohydramnios has a relatively favorable course, as it is not associated with a violation of the integrity of the amniotic membranes. Traumatic or secondary, a much less common form of this pathology, is characterized by damage to the membranes and gradual leakage of amniotic fluid during pregnancy. The discharge of amniotic fluid occurs through the gap formed between the membranes and the inner surface of the uterus. The size of the damage may vary, but, as a rule, its size is small and water leaks in small portions over a long period of time into the abdominal cavity (amnionic hydrorhea). The process of expiration of amniotic fluid can be either constant or periodic. In the case when the amniotic epithelium has the ability to synthesize, such an outflow of water is compensated for some time. Persistent cases of progression of oligohydramnios end in early termination of pregnancy.

A pregnant woman, with a decrease in the amount of water, may notice the appearance of pain in the uterine area. The pain is constant, aching, intensifying with fetal movements and with changes in body position of the pregnant woman herself. Initially, when the disease develops, its signs are slightly expressed; they become noticeable for a woman with the development of severe oligohydramnios and with the addition of fetal malformations (such children are inactive, the heartbeat is slow).

Diagnosis of oligohydramnios during pregnancy

The main diagnostic criterion for pathology is the determination of the discrepancy between the size of the uterus and the true gestational age. For diagnostic purposes, an ultrasound examination can be performed to help determine the exact amount of water, determine the gestational age based on the size of the fetus, identify the presence or absence of fetal malformations, determine its position in the uterus, and also perform a medical genetic examination by chorionic biopsy. This study involves taking material (blood from the umbilical cord or other vessels) under ultrasound control to determine the presence or predisposition to the development of genetic developmental abnormalities.

The course of oligohydramnios during pregnancy

The course of pregnancy with the development of oligohydramnios is characterized by frequent miscarriages - miscarriages in the early stages or premature birth at a later date.

Childbirth in the presence of oligohydramnios also occurs with various kinds of complications. Prolonged labor is the most common. The opening of the uterine pharynx occurs extremely slowly. This situation is explained by the lack of proper functioning of the fetal bladder, which normally leads to adequate smoothing of the cervix and opening of the uterine pharynx. Contractions of the uterus are very painful and do not cause the desired reaction from the advancement of the fetus and, accordingly, the opening of the birth canal.

Consequences of oligohydramnios during pregnancy

One of the common complications of childbirth with oligohydramnios is premature abruption of a normally located placenta. This situation is dangerous for the development of bleeding, up to the death of the mother and fetus. A vaginal (transvaginal) examination during childbirth reveals the absence of tension in the membranes during contractions (flat membranes), while the membranes fit tightly to the presenting part of the fetus and only interfere with the normal course of the dilation period. Spontaneous rupture or artificial dilution of the membranes helps to accelerate the opening of the uterine pharynx and reduce the overall duration of labor. After opening the membranes, a small amount of turbid amniotic fluid is released (often mixed with meconium - fetal feces).

Oligohydramnios leads to adverse pregnancy outcomes, but the severity of the result depends on the stage of pregnancy at which AF pathology began. On the other hand, if oligohydramnios is the only finding in the third trimester, the outcome for the fetus is usually good. Because accurate ultrasound assessment of AFV has its limitations, care should be taken not to overuse the diagnosis of decreased amniotic fluid so that it does not lead to the inappropriate use of invasive interventions during pregnancy, such as early induction of labor. Despite this controversy, it is prudent to evaluate ultrasonographic evidence of decreased amniotic fluid to ensure that this is truly the only finding.

Fetal abnormalities/aneuploidy

Congenital anomalies and fetal aneuploidy are usually associated with oligohydramnios noticed in the second trimester. Most of the fetal anomalies occur in the genitourinary system; defects in the skeleton, central nervous system and cardiovascular system are also associated with oligohydramnios. It is important to remember that secondary oligohydramnios as a result of renal anomalies is not detected until 18 weeks of pregnancy, since maternal contribution to the formation of amniotic fluid remains high until 14-18 weeks. A comprehensive ultrasound assessment of the structure of the internal organs of the fetus, especially the kidneys and bladder, is necessary. Typically, transabdominal ultrasound can accurately diagnose renal agenesis, impaired outflow from the bladder, polycystic kidney dysplasia, and infantile polycystic kidney disease. In the absence of both kidneys and fluid in the fetal bladder, renal agenesis is diagnosed. For further examination of the fetus with renal agenesis, color Doppler sonography is used to determine the location of the renal arteries and identify the “lying” adrenal glands. Ultrasound picture of multicystic dysplastic kidneys and infantile polycystic kidney disease - enlarged hyperechoic or cystic kidneys. With obstruction of the bladder outlet associated with posterior urethral valve syndrome, an enlarged keyhole-shaped bladder and significantly dilated renal pelvis are identified. Due to severe oligohydramnios, accurate antenatal diagnosis of these fetal conditions using transabdominal ultrasound is sometimes difficult.

When visualization of fetal anatomy is poor at the beginning of the second trimester, transvaginal ultrasound is useful. Amnioinfusion has been proposed to improve ultrasound resolution, and the advent of MRI has made non-invasive confirmation of early ultrasound findings possible in most cases. In cases of severe oligohydramnios, it is difficult to perform amniocentesis to assess the fetal karyotype. The method of choice in this case is placental biopsy. With the exception of posterior urethral valve syndrome, where in some cases intrauterine surgery may improve outcome, the fetus is not viable due to pulmonary hypoplasia that develops in these conditions.

Rupture of membranes

Rupture of membranes is easily determined based on history and examination. During vaginal examination, sterile speculum is used to confirm the accumulation of amniotic fluid, determine the alkaline pH with nitrizine and identify the typical phenomenon of arborization. If the anamnesis and examination data are questionable, other methods are used for diagnosis. If, after amnioinfusion of indigo-carmine in Ringer's solution (100-150 ml), the vaginal tampon is stained, this indicates premature rupture of the membranes.

The use of methylene blue should be avoided as it may cause jejunal atresia in the fetus. After 22 weeks of pregnancy, fetal fibronectin is determined in the contents of the posterior fornix, although in uncomplicated pregnancy this test is not very informative. Its determination was used as a non-invasive method for confirming premature rupture of membranes with questionable results of anamnesis and clinical examination. The earlier the premature rupture of the membranes occurred, the more cautious the prognosis. A rupture with the onset of severe oligohydramnios before 24 weeks of pregnancy carries an additional risk of pulmonary hypoplasia, although not as pronounced as with fetal kidney anomalies. If amniotic fluid leaks after amniocentesis in the second trimester, the prognosis is quite good, survival rate is more than 90%.

Intrauterine growth restriction

Uteroplacental insufficiency leads to a redistribution of blood flow in the fetus in favor of vital organs. The patient's history and examination indicate risk factors for intrauterine growth restriction syndrome (IUGR) - drug addiction, chronic hypertension, previous obstetric history, birth weight of children and preeclampsia. Fetal biometry shows fetal weight below the 10th percentile. FGR, detected at the end of the second and third trimester, is characterized by asymmetry of the biometric parameters of the fetus (discrepancy between the head circumference and the abdominal circumference), while with severe FGR in the second trimester, symmetrical growth retardation is observed.

Ultrasound reveals premature maturation of the placenta (early placental calcification). Gives additional hints Doppler study with measurement of blood flow speed in mother and fetus. Abnormal results of Doppler examination of the uterine artery at 18-24 weeks suggest placentation disorders and have some value in predicting adverse pregnancy outcomes. Doppler examination of the umbilical artery reveals an increase in placental resistance, noted with uteroplacental insufficiency. On early stages development of FGR, Doppler examination of the middle cerebral artery of the fetus reveals “brain steal syndrome” associated with the redistribution of blood flow. It is expressed in an increase in diastolic blood flow velocity and a decrease in pulse index. Although there is no separate antenatal study to confirm FGR, pathological dynamic ultrasound results in combination with anamnesis allow one to calculate the prognosis and choose a rational treatment regimen.

Perinatal morbidity and mortality are inversely related to gestational age at diagnosis. In case of early onset severe FGR, the patient must be examined in detail in order to exclude fetal malformations.

Itrogenic causes

Many iatrogenic causes lead to oligohydramnios. These include fetal procedures - chorionic villus sampling or amniocentesis and taking various medications. A careful history can rule out these causes. NSAIDs and angiotensin-converting enzyme inhibitors reduce renal perfusion and lead to oligohydramnios. Fortunately, in most cases, oligohydramnios is reversible when you stop taking these medications.

Postmaturity

A decrease in the volume of amniotic fluid during post-term pregnancy is a reflection of uteroplacental insufficiency, which occurs in late dates pregnancy. In post-term pregnancy, it is recommended to monitor the volume of amniotic fluid and, if signs of oligohydramnios appear, induce labor. However, it is unclear whether these interventions lead to improved fetal outcomes.