Ultrasound norms by week. The length of the femur is less than the gestational age

• Essence of the procedure
• Norms and deviations
• Description of the main indicators
• I trimester
• II trimester
• III trimester

At various stages of pregnancy, fetometry is regularly performed - this is determining the size of the fetus using ultrasound. The data obtained during the examination were subjected to statistical analysis over many years, and on their basis a table was compiled with normal indicators by week.

It is the main parameter for more accurately determining the due date and allows you to find out whether there are any abnormalities in the baby’s intrauterine development. Knowing what it is, young parents themselves can, after an ultrasound examination, make sure that everything is in order.

Essence of the procedure

Most often, ultrasound fetometry is performed either with a transvaginal sensor or traditionally through the abdomen. In the first case, no preparation is required from the woman. Classic ultrasound will show more accurate results if early stages An hour before the procedure, drink 500 ml of water and do not empty your bladder. When filled, it will help improve visibility in the uterine cavity. After 12 weeks this will no longer be necessary, since this function will be performed amniotic fluid.

The procedure is familiar to everyone: a special gel is applied to the stomach, and everything that happens in utero is displayed on a computer monitor. Modern programs allow you to automatically take measurements of the fetus, and the doctor then compares them with a general table of norms by week. This allows you to clarify the duration of pregnancy and timely identify pathologies in the development of the fetus.

Why is it called that? The term “fetometry” goes back to the Latin word “fetus” (translated as “offspring”) and the Greek “metreo” (meaning “to measure, determine”).

Norms and deviations

It is useful for parents to know what the norm is, according to the fetometry table, and when they talk about pathological deviations. Seeing a slight discrepancy between the true sizes and official indicators, many begin to panic and draw incorrect conclusions, which in most cases turns out to be completely in vain.

• the fetal data fully corresponds to the sizes in the table;
• they are behind or ahead of them by less than 2 weeks (this period is acceptable for individual characteristics);
• the indicators are not on the same line, but scattered, but this difference is no more than 1 line: these discrepancies are acceptable due to spasmodic intrauterine development fetus

Everything else is referred to as cases of deviations. It is especially dangerous when the fetometry of the fetus shows for the umpteenth time that the same size is 2 or even more lines larger or smaller than the norm.

For example, a growing head circumference may indicate hydrocephalus, but to confirm the diagnosis, additional data obtained from Doppler and CTG and follow-up will be needed.

For comparison. If all the dimensions of the fetus “fit” into the norm indicated in the fetometry table, except, for example, the length of the thigh, this is not at all an indicator of pathology. Perhaps the parents or other relatives of the child are simply the owners of very long (or, conversely, too short) legs.

If there are deviations, such serious diagnoses as “intrauterine growth retardation” and “hypotrophy” are confirmed by two doctors: not only an obstetrician-gynecologist, but also a medical geneticist. They assess the genetic predisposition of the fetus and determine the causes of the identified pathology (chromosomal abnormalities, bad habits, parental age, intrauterine infection, etc.).

It is very important that the obstetrician-gynecologist is primarily responsible for deciphering the obtained indicators: the ultrasound specialist only provides him with a summary sheet, which indicates what sizes and how much they differ from the norm of fetometry for given period pregnancy. What parameters are taken into account during screenings?

Description of the main indicators

To understand what fetal fetometry data is contained in the tables by week, you need to know the symbols of these parameters and their interpretation.

• BDP - biparietal size, the distance between the parietal bones, describes the development of the nervous system.
• DB - thigh length.
• DG - length of the lower leg.
• DN - length of the nasal bone.
• DP - shoulder length.
• KTP - coccygeal-parietal size.
• LZR - fronto-occipital size.
• OG - head circumference.
• OG (DHA) - breast volume (chest diameter).
• OB - abdominal circumference.
• PDA - transverse diameter of the abdomen.
• PY is the fertilized egg where the baby develops.
• SDA - sagittal diameter of the abdomen (measured in the anteroposterior direction).
• TVP - thickness of the collar space.

This is the breakdown of the indicators that are most often indicated in the fetometry table. It may also include the lengths of other bones - tibia, fibula, ulna, radius, as well as the foot. But they no longer have such importance for identifying pathologies - they are used for comparison only as additional information.

Among other things, you can calculate the weight of the fetus using fetometry performed after the 20th week of pregnancy. All calculations are made automatically by the ultrasound machine itself based on the period, BPR, LZR, coolant, DB and exhaust gas. They give very accurate results and allow you to compare them using a table with standards.

I trimester

The first fetometry is prescribed at 12-13 weeks. Its goal is to identify malformations in the fetus in the early stages of pregnancy.

This ultrasound screening does not determine a specific disease, but only indicates markers that are typical for it. Based on the results obtained, additional studies may be prescribed. All suspicions that arise are confirmed or refuted by invasive laboratory techniques.

Some fetometry indicators may be specified. For example, during the first screening, specialists use a table of average CTE values, since this size is very important for identifying abnormalities in the intrauterine development of the fetus.

Doctors consider an increase in CTE for 1-2 weeks as normal options. If the pregnancy is not complicated diabetes mellitus mother and Rh conflict, this may mean that the baby will be born a real hero and his weight will be more than 4 kg, and this in some cases may be an indication for a cesarean section.

These are the important data that the first fetometry gives to specialists.

About the timing. The first ultrasound screening is carried out during this period due to the TVP indicator. Until the 11th week it is so small that it cannot be measured. And after 14 weeks, this space is filled with lymph, which distorts the results of the study. It is this parameter that is a marker of most chromosomal abnormalities of the fetus.

II trimester

The time frame for the second ultrasound fetometry must fit within the following periods:

• no earlier than 16 weeks;
• no later than 20;
• the best option is week 17, which, if abnormalities are detected, will allow more accurate additional genetic examinations;
• Sometimes an ultrasound is performed at 21-22 weeks, but these are already the most extreme and undesirable dates.

The first ultrasound screening provides the most accurate results, but often even these are not enough to make a reliable diagnosis. To do this, many indicators need to be seen in dynamics. This is precisely what the data from the second fetometry demonstrates.

It performs the following tasks:

• identify defects that cannot be determined in the first trimester;
• confirm/refute the diagnosis previously made based on the results of the first screening;
• determine the level of risk of suspected fetal pathologies;
• detect deviations in the formation of a small organism.

Fetometry of the second trimester is prescribed only to those women who, according to the results of the first ultrasound, are at risk.

Approximate ultrasound standards at this stage of pregnancy are presented in the following tables.

Height Weight

Abdominal circumference

Head circumference

Calf length

Thigh length

Humerus length

Forearm bone length

If for some reason the timing of the second fetometry was shifted, you can use a table with average indicators from 21 to 27 weeks:

After studying the data from the second fetometry, the gynecologist can refer the woman for a consultation with a geneticist or independently prescribe invasive techniques to diagnose suspected pathologies. In cases where the diagnosis is nevertheless confirmed, a decision is made on the further fate of the pregnancy.

If therapeutic adjustment is not possible, artificial induction of labor is performed (about artificial birth, read our article). If the detected pathology is reversible, treatment is prescribed as quickly as possible to save the baby.

III trimester

The third fetometry can be prescribed on any day of the third trimester of pregnancy. The optimal period is 32-33 weeks. Since at this stage it is close to childbirth, ultrasound is performed more carefully than before.

For example, the baby’s face is already clearly visible, which makes it possible to identify pathologies such as a cleft palate or cleft lip. The doctor finds out how developed the fetus is in accordance with the gestational age.

It is usually not recommended to conduct such studies after 34 weeks. However, there are cases when they are prescribed immediately before childbirth (at 37-38 weeks) in order to make the final decision about a caesarean section or natural birth of the baby.

Table of average values ​​of the third fetometry by week

If there are deviations at this stage, the woman is offered hospitalization. If the obtained readings change negatively, doctors may decide to induce premature labor.

Helpful information. Everyone around (women, and often doctors themselves) likes to talk about the importance of the first two fetometry and the optionality of the third. But only it allows you to make the right decision on how to carry out the upcoming birth with minimal losses for mother and baby.

The information from the fetal fetometry tables is for informational purposes only. It is not recommended for parents to draw any independent conclusions by comparing the results obtained with the norms, because they do not always reflect reality and require mandatory interpretation by specialists.

Throughout the nine months, every mother worries about the correct development of the baby. It is to ensure full control over the development of the child in the womb and timely detection of any abnormalities that pregnant women are strongly recommended to regularly visit a leading doctor in order to find out the size of the fetus by week of pregnancy.

Accurate diagnosis involves the use of ultrasound methods. Based on the results obtained, the specialist can determine how proportionally the baby is developing, and whether the data obtained regarding growth and development correspond to established standards.

What indicators are taken into account?

The key parameters that make it possible to determine the characteristics of fetal development are indicators of its height and weight, but they begin to be measured only in the second part of the first trimester. Until that time, the size of the embryo is so small that measuring it is extremely difficult.

According to medical indications, every pregnant woman is required to undergo at least three ultrasound procedures throughout the entire nine months. This number of procedures is considered minimal and can be increased by the decision of specialists if there is a need to obtain additional information about fetal development.

Periodic ultrasound is necessary for the timely detection of serious pathologies and the prevention of complications. As a rule, such studies are carried out no earlier than 10 and no later than 14 weeks, as well as in the second trimester from 18 to 21 weeks.

To make the task easier, in medical practice it is customary to measure the size of the fetus by weeks, because the fertilized egg increases in volume almost daily.

The results of each ultrasound are recorded in protocols, from which information can be obtained regarding the symmetry of fetal development, its growth rate and compliance of indicators with established and used standards.

Throughout pregnancy, various parameters are taken into account as the fetus develops. For example, until the 13th week, experts focus more on analyzing the coccygeal-parietal length, measured from the coccyx to the parietal region of the fetus. This measurement feature is due to the fact that the fetus is in a bent position, so the opportunity to obtain the first data on growth appears no earlier than the 14th week.

During the second planned ultrasound, specialists focus more on other indicators presented:

• fronto-occipital size or longitudinal line;
• circumferences of the skull, abdomen and chest;
• the length of the lower and upper limbs.

An important factor indicating the normal development of the fetus is not only compliance with established standards, but also the symmetry of the measurements obtained

Fetal size by week of pregnancy

Pregnancy occurs at the end of the second week of the menstrual cycle, which is considered the moment of conception. The features of this process are known to everyone from school. Male ejaculation is accompanied by the release of millions of sperm, only one of which, after entering the vagina and through the fallopian tubes, will be able to approach the egg.

During the third week, the formation of a germinal vesicle occurs, inside which there is fluid and cells in large quantities. This bubble is so small that it is almost impossible to see it without special equipment. To be able to imagine the parameters of a bubble, compare it with a pea, the size of which does not exceed 0.2 mm in diameter.

From the beginning of the fourth week, active development of the fetus begins, which almost doubles in size every week. So, by the end of the next week, the length of the fertilized egg reaches 0.5 mm. Already at this stage, specialists have the first opportunity to obtain real data on fetal development, which can be presented in the form of a table.

Table 1. Dimensions of the fertilized egg from 1 to 13 weeks

The lengths given in the table are measured from the crown to the tailbone and are averaged. According to experts, due to the distinctive features of development, minor deviations from the given average indicators are allowed. A significant deviation, as well as a violation of acceptable proportions between indicators, which is an important factor, is a prerequisite for further research.

By the end of the eighth week, the length of the fertilized egg reaches 11 mm. According to numerous studies, the weight of the fetus at this stage does not exceed 1.5 grams. Over the next week, weight increases by another 0.5 g, and by the end of the tenth week it can reach 4 g.

On the eleventh, through ultrasound examination, it becomes possible to obtain the first data regarding the length of the thigh and chest, which are 7 and 20 mm, respectively. By this period, the weight of the fetus reaches 11 g. By the end of the 12th week, the diameter of the chest will reach 24 mm, and the diameter of the thigh - 9 mm.

From the 11th to the 40th week, specialists carefully examine not only the general length indicators, but also the parameters of individual parts of the body, which allows them to get a general and complete picture of the correct development of the fetus.

Starting from the thirteenth, during examinations, measurements of the baby’s skull are also taken into account, whose weight by this time reaches 30 g.

Table 2. Sizes of the fertilized egg by week: from 13th to 40th

Biparental fetal size by week

Another important indicator that experts take into account in their research is the biparietal size, represented by the distance between the outer surface of the upper contour and the inner region of the lower contour between the parietal bones.

As is the case with other indicators, when analyzing the resulting biparietal size, minor deviations from the norm are allowed. If the established data is exceeded, the specialist must evaluate other parameters, represented by abdominal circumference and limb length.

Analysis of this indicator is extremely important, because its deviations from the norm in many cases may indicate serious pathologies, represented by hernias, tumors and other space-occupying formations, in which the only way out may be termination of pregnancy. Insufficient development of the baby’s head or a decrease in its size is also considered undesirable, which may be due to underdevelopment or absence of anatomical structures of the brain. In this case, experts also strongly recommend termination of pregnancy.

Often, in the third trimester, reduced indicators of BPD are diagnosed, which, if detected in a timely manner, can be successfully corrected.

As a rule, in this case, a diagnosis of intrauterine growth retardation is made, and the pregnant woman is prescribed treatment with medications that help improve uteroplacental blood flow and ensure the transport of necessary nutrients.

In medical practice, the following average indicators of biparietal dimensions of the fetus are used:

• 8 week – 6 mm;
• 9 week – 8.5;
• 10 week – 11 mm;
• 11 week – 15 mm;
• 12 week – 20 mm;
• 13 week – 24 mm;
• 14 week – 26 mm;
• 15 week – 32 mm;
• 16 week – 35 mm;
• 17 week – 39 mm;
• 18 week – 42 mm;
• 19 week – 44 mm;
• 20 week – 47 mm;
• 21 weeks – 51 mm;
• 22 week – 54 mm;
• 23 week – 58 mm;
• 24 week – 61 mm;
• 25 week – 64 mm;
• 26 week – 67 mm;
• 27 week – 69 mm;
• 28 week – 72 mm;
• 29 week – 75 mm;
• 30 week – 78 mm;
• 31 weeks – 80 mm;
• 32 week – 82 mm;
• 33 week – 84 mm;
• 34 week – 86 mm;
• 35 week – 88 mm;
• 36 week – 90 mm;
• 37 week – 91 mm;
• 38 week – 92 mm;
• 39 week – 94 mm;
• 40 week – 95 mm.

Weight indicators

Of course, it is not possible to establish the exact weight of the fetus through ultrasound examination, so experts rely on other sizes and established norms. For the first time, the weight of the fetus is indicated in the eighth week, from which it becomes possible to obtain the first necessary data.

Table 3. Fetal weight by week

As a rule, from the data obtained after an ultrasound examination, it is not easy for many women to understand how large the fetus is at this stage. To facilitate this task, the size of the fertilized egg by week can be compared with well-known objects. As already noted, the first indicators of fetal length can be obtained only in the third week, when its diameter is 0.2 mm. It is extremely difficult to examine the fruit at this stage, and it can only be compared with a poppy seed.

By the end of the fourth week, the fruit almost doubles in size and can now be compared in size to sesame seeds. By the end of the fifth period, the fertilized egg acquires dimensions comparable to sunflower seeds.

Do you know which bird is considered the smallest on the planet? These are hummingbirds, the size of which rarely exceeds 5.7 centimeters, and the weight ranges from 1.6 to 2 g. It is with the egg of this bird that the size of a human fetus can be compared in the sixth week of its development. By the end of the seventh, its dimensions are comparable to those of an ordinary bean.

By the eighth, the fruit can be compared in parameters to an unripe olive, and by the end of the ninth - to a large grape.

At the tenth week, the fetus reaches the size of a candy, which doctors do not recommend that pregnant women eat. The fruit reaches the size of an apricot by the end of the next period, used as a unit of measurement. At the 12th week, the fruit can be compared to a pea pod, and by the end of the thirteenth - to a ripe fig.

Over the next 7 days, the fruit will grow to the size of an average pear, and after another week - to the size of an avocado. The average weight of newborn kittens is about 100 g. This is how much a human fetus weighs at the 16th week of its development, and its length can be compared to an average carrot.

At the 17th week, the fetus can be compared to a medium potato, and at the end of the eighteenth week it can be compared to a large tomato.

Imagine holding a big banana in your hands. This is exactly the size the baby reaches by the end of the nineteenth period. At week 20, it can be compared to a small bunny. Have you ever seen such an exotic fruit as Thai mango? At 21 weeks, the weight of the fetus can be compared with it.

Among penguins, the largest and heaviest are representatives of the Imperial species, whose height often reaches 125 cm and weight - 50 kg. Emperor penguin eggs weigh up to 450 g. This is how much a human fetus weighs at 22 weeks of development.

At week 23, in terms of length, it can be compared with the weight of a corn cob, and by the end of week 24 - with the weight of a green coconut. By the end of the next period, the size of the baby in the womb can be compared with newborn polar bear cubs, which, despite the impressive volume of adults, are born quite small.

By the end of the 26th week, the baby's weight can be compared to an average head of broccoli, and by the 27th week - to the weight of a pomelo fruit.

If we take for comparison the length of the baby from the heels to the top of the head, then at 28 weeks it is comparable to the growth of a newborn tiger cub. The largest bird on the planet is the African ostrich, whose height can reach 200 centimeters and weight 120 kg. The eggs of these birds weigh on average 1,200 g. This is the weight that is considered normal for a baby at 29 weeks of development.

By the end of the next period, the child is comparable to the weight of a six-month-old kitten, and by the end of 31 weeks - with the weight of a newborn lion cub.

In terms of growth, a child at 32 weeks can be compared to a small blue penguin, and by the end of the next period he reaches the weight of an average pineapple. At week 34, the baby acquires the size of a ripe melon with average parameters.

After the next seven days, the baby’s weight becomes comparable to the weight of a small pumpkin, and after another 14 days, it becomes comparable to the size of a watermelon.

By the end of the thirty-ninth week, the baby’s length reaches 50 cm. It is with these lengths that dolphins are born. By the end of the 40th week, the baby can already be safely compared with the average newborn baby who is ready to meet the world.

Take care of your health and future offspring. I wish you a safe birth and excellent health.

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Ultrasonography, or ultrasound is an examination method that is widely used during pregnancy at any stage. This diagnostic test is relatively simple, highly informative and safe for both mother and child. The main objectives of ultrasound during pregnancy are:

1. Confirmation of pregnancy;
2. Measuring the size and weight of the fetus, the correspondence of these data to the gestational age;
3. Assessment of fetal viability;
4. Determination of fetal development abnormalities;
5. Determination of the size of the placenta, its degree of maturity and place of attachment;
6. Determination of quantity and quality amniotic fluid(amniotic fluid);
7. Determining the sex of the child.

Ultrasound examination during pregnancy is screening method examinations, i.e. it is mandatory for every pregnant woman. According to the order of the Ministry of Health of the Russian Federation No. 457 “On improving prenatal diagnostics in the prevention of hereditary and congenital diseases in children,” a three-time screening ultrasound examination was approved:

• the first ultrasound is performed between 10 and 14 weeks;
• second – from 20 to 24 weeks;
• third - from 32 to 34 weeks.

It is important to know that problems may arise at any time due to which the doctor will prescribe additional ultrasounds.

Most common reasons for this are:

• Nagging pain in the lower abdomen;
• The appearance of bloody discharge from the vagina;
• Inconsistency between the size of the fetus and the gestational age;
• Abnormalities of placenta attachment;
• Multiple pregnancy;
• Incorrect fetal positions.

Can be used for ultrasound examination two types of sensors: vaginal (examination is carried out through the vagina) and abdominal (the emitter is applied to the abdomen through a small layer of special gel). During an abdominal ultrasound, a woman should prepare: drink at least 1-1.5 liters of fluid 1 hour before the procedure to fill the bladder. When using a vaginal sensor, no special preparation is required; in this case the bladder, on the contrary, must be emptied.

information As a rule, the doctor begins the examination using the abdominal method. If the fetus is poorly visualized, which often happens in the first trimester, then proceed to vaginal ultrasound.

Most pregnant women during the study are concerned about the duration of pregnancy and the expected date of birth. In this case, ultrasound can provide the most accurate data when performed in the early stages (up to 12 weeks), then the result can be influenced by various factors, primarily the size of the fetus itself.

Below is a table of fetal length and weight for each week of pregnancy, but keep in mind that these are just averages and your baby may differ from these readings.

Fetal size table by week

The following tables provide data on fetal biometrics that are measured during each ultrasound. They are presented at the 10th, 50th and 95th percentiles. Most often they focus on the 50th percentile, and the rest are considered normal fluctuations.

Dimensions of the fetal head by week of pregnancy

Abdominal and fetal head circumference

Length of shin bones and femur fetus

Length of fetal humerus and forearm bones

Norms at the first ultrasound at 10-14 weeks

The first screening ultrasound is performed at 10-14 weeks. Its main tasks are:

• Study of the thickness of the collar zone(area between soft tissues, covering the spine and the inner surface of the skin, filled with fluid). Assessing the size of the neck fold is very important because... is enough in an exact way timely diagnosis of various chromosomal diseases, in particular Down syndrome. If there is an enlarged nuchal space, the doctor should refer the pregnant woman for consultation with a geneticist. The woman is prescribed additional examination methods: a blood test for alpha-fetoprotein and human chorionic gonadotropin, invasive diagnostic methods (amniocentesis - study of amniotic fluid, placentocentesis - study of placental cells, cordocentesis - study of blood taken from the fetal umbilical cord).

Normal values ​​of the nuchal translucency (NVP) in the first trimester of pregnancy

• Measuring the coccygeal-parietal size (CTP)). This is an important indicator by which you can determine the size of the fetus and approximate period pregnancy.

Values ​​of the coccygeal-parietal size by pregnancy

Important

• Study of fetal cardiac activity. The fetal heartbeat is the main indicator of its viability.

Normally, heartbeats should occur at regular intervals, i.e. be rhythmic. Arrhythmia may indicate the presence of a congenital heart defect or fetal hypoxia. The heartbeat should sound very clear and distinct; if there are dull tones, intrauterine oxygen deficiency can be suspected. An important indicator is heart rate.

Normal heart rate by stage of pregnancy

Tachycardia is an increase in the number of heartbeats more than normal, bradycardia is a decrease in heart rate to 120 beats per minute or less. Most often, such changes in heart rate occur during fetal hypoxia as a reaction to a decrease in oxygen in the blood. In such cases, the pregnant woman must be prescribed treatment, which is often carried out in a hospital setting. Therapy is prescribed aimed at improving uteroplacental blood flow and improving intracellular metabolism.

• Assessment of the development and presence of various organs(bladder, kidneys, liver, stomach, heart), spine, and also the upper and lower extremities of the fetus. If abnormalities in the development of organs are detected, the woman is referred to a genetic consultation. After a detailed examination, a geneticist decides on the viability of the child and possible termination of pregnancy.

Normal indicators of the second ultrasound at 20-24 weeks

The doctor prescribes a second planned ultrasound at 20-24 weeks. At this time, the following are examined:

1. Biometrics(biparietal size, fronto-occipital size, length of tubular bones, abdominal and head circumference). These indicators are measured to assess the growth of the fetus and its size according to the gestational age.
2. Detection of various fetal malformations. It is during this period that diagnostics will be the most informative, because during the first examination, the child is still too small, and during the third planned ultrasound it will already be too big; in addition, at longer periods, the placenta may interfere with a thorough examination if it is located on the anterior wall of the uterus.
3. Structure, thickness, location and degree of maturity of the placenta. This is the most important organ that supplies the fetus with all the nutrients necessary for its normal development.

Normal thickness of the placenta depending on the stage of pregnancy

If the thickness of the placenta increases, the doctor may suspect the presence of placentitis (inflammation of the placenta). Making such a diagnosis requires additional examination for the presence of infection and subsequent treatment in a hospital.

Ultrasound also evaluates degree of maturity of the placenta. This is an important indicator characterizing the ability of the “baby place” (synonymous with the term “placenta”) to provide the fetus with the necessary substances.

Degrees of placenta maturity

Late maturation of the placenta It is quite rare and is mainly caused by:

• Mother's smoking
• She has various chronic diseases.

Premature maturation of the placenta occurs more often. The causes of this condition are:

1. Smoking,
2. Maternal endocrine diseases (in particular diabetes mellitus),
3. Intrauterine infections
4. Preeclampsia,
5. History of abortion.

When such diagnoses are made, the pregnant woman is prescribed an examination: Dopplerometry, CTG, tests for possible infections. In the future, the woman must undergo a course of treatment. Drugs are prescribed to treat fetal hypoxia, vitamin therapy, antispasmodics to reduce uterine tone, and in the presence of infection, antibiotic therapy.

An equally important task for an ultrasound diagnostic doctor is to study placenta attachment site. Most often, the “baby spot” is attached to the posterior wall of the uterus, less often - to the front and even less often - in the fundus. Normally, the placenta should be 6 cm or more away from the internal os of the cervix.

If it is located lower and covers the internal os of the uterus, they speak of placenta previa. This is a serious type of obstetric pathology that threatens the life and health of the woman and child. Often this anomaly occurs in multiparous women, after inflammatory diseases of the uterus, uterine fibroids, and after abortions. The pregnant woman is carefully observed in the hospital or at home, where she must remain completely at rest and abstain from sexual activity. If bleeding begins, immediate hospitalization is required.

Quantity and quality of amniotic fluid

Average normal amniotic fluid index values

When the amount of amniotic fluid changes in one direction or another, they speak of polyhydramnios and oligohydramnios.

Polyhydramnios often occurs in women with infectious diseases, diabetes mellitus, multiple pregnancy, some fetal malformations, Rh sensitization (incompatibility of the blood of mother and fetus according to the Rh factor). The condition requires mandatory treatment: antibiotic therapy, drugs that improve uteroplacental blood flow.

Oligohydramnios is a pathological decrease in the amount of amniotic fluid to less than 500 ml. The causes of this condition are still unknown. If there is very little water, this may indicate a severe malformation of the fetus: the complete absence of kidneys. There is practically no treatment for oligohydramnios; all therapy is aimed at supporting the child.

The ultrasound specialist also evaluates amniotic fluid quality. Normally they should be transparent. If there is turbidity, mucus, or flakes in the amniotic fluid, there is a suspicion of an infectious process. The woman is tested for hidden infections and undergoes treatment.

1. Umbilical cord assessment. Ultrasound examination can detect the entanglement of the umbilical cord around the fetal neck. But in the second trimester of pregnancy it does not cause alarm. The baby is in constant motion, and the umbilical cord can become untwisted.
2. Cervical assessment. Normally, the cervix should be at least 3 cm, and only closer to childbirth it begins to shorten and smooth out. The internal opening must be completely closed. Shortening of the cervix or opening of the pharynx is a sign of isthmic-cervical insufficiency. The woman must have her cervix stitched or have an obstetric pessary inserted (a mechanical device in the form of several rings that is inserted into the vagina and protects the cervix from premature dilatation).

Third ultrasound at 32-34 weeks

The third planned ultrasound is performed at 32-34 weeks. Its tasks are:

1. Determination of fetal position and presentation. At this stage, the child is already quite large and his mobility is limited. The position in which he is during the ultrasound will remain until the end of labor. Determining these indicators is important for deciding the method of delivery. There are longitudinal, transverse and oblique positions of the fetus. When the baby is positioned longitudinally, a woman can give birth naturally, transverse and oblique position are relative indications for cesarean section. Natural childbirth are also possible with a normal cephalic presentation of the fetus; pelvic position is an indication for surgical delivery.
2. Estimation of fetal size and weight. These indicators help to understand how the child is developing. If the size of the fetus lags behind the average, intrauterine growth retardation may be suspected. Determination of fetal malnutrition requires initiation of treatment for the pregnant woman. If the fruit, on the contrary, is ahead of the indicators, then we can talk about a large fruit. The birth of a baby with a large weight (more than 4 kg) is likely. This can significantly complicate childbirth, so women are often offered operative delivery.
3. Study of the placenta, its size, degree of maturity and place of attachment. The migration of the placenta at this stage has already been completed; it will occupy the same position at birth. It should be borne in mind that in case of complete presentation, childbirth is possible only by caesarean section. If the baby's place is low, it is possible to give birth through the vaginal birth canal, but this is fraught with a high risk of bleeding during childbirth.
4. Assessment of the quantity and quality of amniotic fluid(see topic: normal indicators of the second planned ultrasound at 20 - 24 weeks).

Normal ultrasound before childbirth

Ultrasound examination before childbirth is not mandatory for all pregnant women and is carried out selectively according to indications. Its main task is to resolve the issue of the method of delivery. During an ultrasound, the following is determined:

1. Position and presentation of the child;
2. Estimated fetal weight at birth;
3. Position the umbilical cord to avoid entanglement.

In the process of bearing a baby, expectant mothers have to undergo a large number of examinations, including fetometry of the fetus using ultrasound. This is one of the few non-traumatic procedures that can provide reliable information about the condition and development of the child throughout pregnancy.

Fetal fetometry, as a method, is the determination of the size of the baby through ultrasound scanning and comparison of the obtained data with existing standards. This information allows the attending physician to judge the occurrence of developmental abnormalities or the normal process of gestation.

If there are difficulties in determining the time of conception based on the last menstruation, fetal fetometry allows you to determine it with an accuracy of up to 4 days. Therefore, we can say that this method is in demand in the early diagnosis of intrauterine development disorders and specifying the timing of pregnancy. All standards for fetal fetometry indicators are adjusted to international medical standards and are indicated in tables with average statistical data.

Periods of fetometric examination

Ultrasound examinations for the purpose of diagnosing the development of the baby are usually timed to the 12th, 20th and 32nd weeks of pregnancy. There is one diagnostic procedure for each trimester.

The decision regarding the time of ultrasound and fetometry is made by the doctor. This is affected by:

• general condition of the expectant mother;
• suspicion of a violation of the intrauterine development of the child;
• established timing of fetal fetometry.

Thanks to ultrasound, it became possible not only to assess the main characteristics of the fetus (calculate the weight of the fetus using ultrasound, its height, chest and head circumference) and correlate them with the average statistical indicators for weeks of pregnancy, but also to identify the functional state internal organs child, determine its gender.

Key characteristics of fetometric research

The leading criteria for fetal fetometry are:

• KTR (coccygeal-parietal size);
• BPR (biparietal head size);
• OG (chest circumference);
• AB (abdominal circumference);
• DB (femur bone length).

Table with average fetal fetometry values ​​by week of pregnancy:

Additionally, the following ultrasound indicators can also be determined:

• fetal head circumference;
• fronto-occipital size;
• length of the tibia bone;
• tibia length;
• foot length;
• length of the bones of the shoulder and forearm;
• interhemispheric cerebellar size (IMD);
• heart diameter.

CTE as a characteristic of the physical development of the fetus

Variants of the norm include an increase in CTE for one to two weeks. If Rh conflict, neoplasms and diabetes of the mother are excluded, then such an increase in the size of the baby may indicate that the child will be born large, weighing more than 4 kg.

In this case, you need to use medications that affect metabolism, including complex vitamins, with caution. Such drugs can lead to the birth of a very large child from 5 kg.

The reasons that can lead to a decrease in CTE can be both normal variants and a sign of severe pathology.

To standard options refers to the possibility of later fertilization due to the timing of ovulation. As you can see, the time of conception will be slightly later than calculated according to the last day of menstruation. In this situation, you just need to repeat the ultrasound in a week.

Pathological causes:

1. Frozen pregnancy and embryo death. This situation requires immediate intervention and medical care, because can cause bleeding, disruption of the reproductive functions of the female body, toxic shock and death of the mother. This pathology can be excluded if the heartbeat of the unborn child is determined.
2. Lack of hormones (usually progesterone) requires confirmation using additional research methods and hormonal therapy (only a doctor can prescribe it!). Treatment is mandatory, because hormonal deficiency can cause self-abortion.
3. Infections, including STIs, can become a factor that negatively affects the baby's growth. In this situation, additional examinations are required to identify the infectious agent. Then therapy should be carried out within the permitted time frame.
4. Genetic abnormalities (syndromes: Down, Patau, Edwards). If such disorders are suspected, genetic consultation and additional examinations are required. Serious genetic abnormalities usually lead to self-abortion.
5. Somatic diseases of the mother, including chronic heart and thyroid diseases. As a rule, they exert their influence at a later date. And yet, their influence cannot be excluded from the first week of embryo development.
6. Pathology of the mucous membrane lining the uterus. Erosion, abortion, fibroids, violating the integrity of the mucous layer, prevent the fertilized egg from properly attaching to the uterine wall and growing fully, which can cause self-abortion.

CTE is an important indicator of the development of the baby, but do not rush to interpret its value yourself, wait for the comments of the attending physician.

BDP as an indicator of the development of the fetal nervous system

The biparietal indicator, measured during fetometry, indirectly describes the development of the baby’s nervous system and indicates the gestational age with a high degree of accuracy. In fact, BPR on ultrasound is the distance between the outer visible boundaries of the oppositely located parietal bones of the skull (right and left), which is determined along the line of the eyebrows. Often this parameter is measured together with the LZR indicator (fronto-occipital size) - the distance between the outer visible boundaries of the bones: occipital and frontal.

The characteristics of the BDP are used to determine the degree of safety for the mother and child of its passage through the birth canal during the process of delivery. In cases where the BPR value significantly exceeds the norm, surgical delivery by cesarean section is indicated.

The BPR indicator in combination with the LZR indicator allows you to evaluate the characteristics of the baby’s brain and the development of the baby’s nervous system on a weekly basis. A feature of biparietal characteristics is that their growth slows down with increasing gestational age.

At twelve weeks, the growth of the BPR indicator is about 4 mm per week, by the end of the gestation period it barely reaches 1.3 mm. A competent interpretation of this indicator makes it possible to high level reliably assess the growth and development of the baby throughout the entire period of gestation.

Minor fluctuations in biparietal and fronto-occipital indicators may be variations in the baby’s normal growth. For example, if the fruit large sizes(over 4 kg), then all parameters can be increased for a period of one to several weeks. Also, sometimes the head grows slightly larger/smaller than other organs, because the baby grows unevenly. In this situation, you need to repeat the ultrasound in a few weeks, perhaps the indicators will level out.

A significant increase in these indicators can be an alarming symptom, indicating the development of neoplasms of bone or brain structures, the appearance of cerebral hernias and the accumulation of cerebrospinal fluid in the ventricles of the brain (hydrocephalus/dropsy):

• If neoplasms and cerebral hernias develop, it is recommended to terminate the pregnancy. A fetus with such a pathology is usually not viable.
• Hydrocephalus, in most cases, occurs due to intrauterine infection. The infection must be treated with antibiotics. If this treatment does not work, it is recommended to terminate the pregnancy. If there is no development of hydrocephalus, the fetus is usually allowed to be preserved, but its condition must be constantly monitored by ultrasound.

A decrease in the size of the fetal head may indicate insufficient development of certain brain structures, or the absence of them. The absence of any brain structures is a strict indication for termination of pregnancy, regardless of the period at which this pathology was discovered.

Another reason for the decrease in BPD and LZR is the violation of the timing of fetal development. This phenomenon requires immediate medical intervention and correction, because may cause intrauterine death of a child.

For the entire period of pregnancy, if future mom registered on time antenatal clinic, she will have to undergo several important tests, including an ultrasound. Exactly this procedure allows you to observe the fetometry of the fetus and monitor the development of the baby.

Fetal fetometry by week of pregnancy is an intrauterine measurement of the baby to determine how the baby’s body is developing, to identify possible disorders or diagnose other problems.

The fetal fetometry is measured in millimeters, and the data obtained is checked against special tables, from which the state of pregnancy becomes clear. Each week of pregnancy has its own fetometric indicators.

More about the study

Fetal fetometry – absolutely safe method research on weeks of pregnancy, as it is carried out using ultrasonic waves, which do not have a negative effect on the body of the fetus and the pregnant woman;

This method is non-invasive - that is, it does not require disruption of the integrity skin, mucous membranes or blood sampling;

Can be performed as many times as medical indications require;

Fetal fetometry makes it possible to dynamically monitor its growth week by week and the condition of its organs;

The study also makes it possible to determine indicators indicating developmental disorders and anomalies, genetic diseases in the fetus during a routine ultrasound examination of a pregnant woman.

How to prepare for research

Fetometric measurements of a developing baby in utero are carried out during an ultrasound. This study can be performed either with a transvaginal sensor or through the anterior abdominal wall.

If the procedure will be performed through the vagina, there is no need to prepare for fetal fetometry. If you are planning a transabdominal test, then in the early stages of pregnancy you will need to drink about half a liter of water an hour before the test and not go to the toilet after that.

This is necessary so that through a full bladder, like through a window, you can look into the uterine cavity. After 12 weeks, this is no longer required, since the necessary “window” is created by amniotic fluid.

When and how does the research take place?

Fetometry is carried out as planned three times, as is ultrasound diagnostics:

• in the first trimester (at 11-12 weeks);
• in the second (at 20-22 weeks);
• in the third (mostly at 32 weeks).

If there are indications or any reasons for additional examinations, then the doctor will refer you to an unscheduled procedure.

I trimester

In the first trimester, as part of a fetometric study, the diagnostician will confirm the due date expected by your gynecologist. The main task of the doctor at this stage is to exclude chromosomal abnormalities and gross malformations. The most important indicators now will be the coccygeal-parietal size (CTR) and abdominal circumference.

Also, during the screening ultrasound examination, both the thickness of the collar space and the length of the nasal bone are measured.

II trimester

An ultrasound examination in the second trimester is carried out to check the absence of intrauterine development disorders. For this, basic measurements are taken: biparietal size of the fetal head, CTE, head circumference, abdominal circumference, fronto-occipital size.

Perhaps other indicators will be taken: the length of the baby’s hip and the length of other bones (tibia, humerus, ulna). At this doctor's visit, you have the chance to find out the sex of your unborn baby.

III trimester

Diagnosis in the third trimester no longer sets itself the task of looking for any defects or disorders, because before this time the baby is already fully formed and preparing for birth.

Now it is important for the doctor to check his well-being and health status. He will also measure the circumference of the head and abdomen, look at how symmetrically the child’s limbs develop, and determine his weight and height.

These indicators will be important for choosing a method of delivery (too large fetal size, first pregnancy, narrow pelvis and other features may cause a referral for cesarean section). If everything is in order, no further procedure is prescribed.

Forms of developmental delay

Several forms of fetal growth retardation have been identified, which can be determined through fetal fetometry at different weeks of pregnancy

1. The symmetrical form is fixed when all indicators of the fetometric study are lower than normal values ​​for this stage of pregnancy;
2. With an asymmetric form, the diagnostician will observe the norm in relation to some parameters, and preferential decreases in some other indicators.

There are also three degrees to determine the lag in fetometry parameters:

• 1st degree means a difference from the norm of two weeks;
• 2nd – at 3-4;
• 3rd – more than a month.

Sometimes the doctor repeats the procedure after some time, and the parameters return to normal, so you shouldn’t just be scared if the numbers of your study differ from the book values.

If there is a big difference, additional diagnostic methods will be prescribed to rule out all kinds of pathologies and defects, developmental disorders, stoppage or delay of vital activity.

What is measured - fetal fetometry at different weeks of pregnancy

There are several growth parameters related to the state of the baby’s skeletal system. The main indicators for the age assessment of the baby are:

• KTR (coccygeal-parietal size), which corresponds to the length from the crown of the child to the coccygeal region and indicates the state of the fetal growth index.
• BDP (biparietal size), which corresponds to the width of the baby’s head between his parietal bones of the skull.
• LZR (fronto-occipital size), which corresponds to the width from the child’s frontal bone to the most protruding point of the occipital bone.
• DB (thigh length).
• OB (abdominal circumference), which is also used to assess growth rates.
• OG (chest volume).
• Lengths of various bones of the skeleton (forearm bones, femur and humerus).

Fetal fetometry table by week

Typically, a young mother is recommended to undergo this examination towards the end of the 1st trimester, in the middle of the 2nd and closer to the time of birth, so women are often very interested in the norm of fetal fetometry at 20 weeks and 30 weeks, as the most important milestones. This data can be obtained from the table below, which shows the desired indicators for each week, starting from the 12th to the 36th. All parameters, except CTE, are indicated in mm.

It should be said that these fetometric norms for weeks, although given in the form of a specific number, in reality have a certain range of values, because it is impossible to bring all organisms to a single denominator. Each of the parameters has its own number of units by which it can shift towards decreasing or increasing: for example, for abdominal circumference it is approximately 14 units in each direction, and for biparental head size it is only 3-4 units in each direction.

As for possible deviations from the norm, they are mainly checked using the KTE parameter - if it does not coincide with the specified value for a certain week, perhaps the gestational age was measured incorrectly. Or, in case of a serious lag or advance, as well as a lack of dynamics, the doctor may talk about:

• frozen pregnancy;
• pathologies in the development of the baby;
• progesterone deficiency in the mother's body;
• infectious diseases that affect the development of the fetus;
• pathologies of the uterine mucosa.

Conclusion

It should be borne in mind that the average values ​​​​are recorded in the plate, and the sizes of each baby may differ. This depends on many factors, including heredity. Therefore, if a child is slightly smaller than normal, this is not a reason to worry; you need to monitor his growth dynamics. If it is positive, it may be individual feature child development.

The information from the fetal fetometry tables by week of pregnancy is for informational purposes only. You should not interpret your screening results on your own. In case of non-compliance with the standards, the doctor will individually determines how critical it is. If the deviations are undesirable, then it is possible to correct the situation by taking the necessary measures in a timely manner. You can read about what other studies pregnant women need to undergo.

Table showing femur length by week , helps to understand the dynamics of its growth during fetal development. It is necessary to identify all kinds of deviations in early stages thanks to the norm indicators presented in the table.

Why is it important to track fetal femur length?

This bone is the thickest and longest in the human body. It takes on the function of maintaining the balance of the body and a large share of the load on it.

Interesting! Due to such a responsible role, a significant number of pathologies in this area are caused by injuries to the hip bone.

By measuring the longest bone of the fetus, the degree of its growth in length is revealed. With the help of such diagnostics, a specialist confirms the compliance (or non-compliance) of the indicators with gestational age.

This information allows us to judge the presence of possible pathologies or the likelihood of their development. This is especially important in cases where one of the parents has some form of femoral bone anomaly: the risk of certain diseases in this area increases if there is a genetic predisposition. For example, osteogenesis imperfecta, characterized by increased fragility of bones (otherwise known as “crystal man” disease), can lead not only to intrauterine fractures, but also to death if timely diagnosis is not available.

In addition, in some cases, it is the data obtained through diagnostics that raise the question of the advisability of treatment or medical intervention even before birth. If the presence of pathologies is confirmed, parents also have the opportunity to prepare for special care for their unborn child.

How does the hip bone grow?

While a person grows, his bones also grow - both in length and width. To understand due to which part the femur grows in length, it is necessary to imagine that in this case growth is observed mainly in non-ossified zones. These include tissues located between the diaphysis and epiphysis. However, the length of the femur also increases partly due to the formation of new tissue particles between the already formed ones. This growth is ensured by cartilage located in the area between the bone body and the ends of the bone.

Growth in thickness is possible due to the division of periosteal cells. In this case, new layers are deposited on the joint surface. It is the periosteum that has the ability to restore destroyed bone particles, so healing of fractures in most cases is explained by its activity.

For reference! Throughout life, a person’s bone substance is subject to destruction and new formation. Bone replacement, according to a study, occurs in people once every six months.

How to find out the growth dynamics of the femur?

Pregnant women undergo many different examinations during all three trimesters, including such an important procedure as fetometry. This is a method that makes it possible to determine the size of the fetus using ultrasound for subsequent comparison of the final indicators with the standards.

The main criteria that are considered during this survey include the following points:

• biparietal size;
• size from coccyx to crown;
• abdominal circumference;
• chest circumference;
• thigh bone length.

These data are indicated in millimeters, and the weight and total height of the fetus are indicated in grams and centimeters, respectively.

In some cases, the length dimensions of the following sections may also be required:

• tibia;
• tibia;
• bones of the forearm and shoulder;
• feet;
• nose

If specific pathologies are suspected, the following data is sometimes required:

• Head circumference;
• cerebellar size;
• fronto-occipital size;
• diameter of the fetal heart.

It is on the basis of the information obtained during fetal fetometry that the attending physician draws conclusions about the norm or abnormality of development.

Femur Length Chart

The average femur lengths corresponding to different weeks of pregnancy can be seen in the table.

It is important to understand that these are average indicators, minor deviations from which, up or down, should not be a cause for concern. However, in cases where the size lags behind the standards by two weeks or more, we can talk about fetal malnutrition.

If the normal dimensions are exceeded, additional research methods will be needed. As a rule, this does not apply to the total weight of the fetus, since its excess is most often caused by excess weight of the pregnant woman, as well as genetic predisposition.

Important! Ancillary studies are usually carried out in cases where a specific part of the body exceeds the norm.

Congenital pathologies of the femur bone

The main anomalies of this zone include three congenital diseases that must be treated specifically in childhood. Otherwise, they can lead to disability and other serious complications.

Underdevelopment of the femur

In almost half of the cases, this pathology is complemented by the absence of the patella or another similar pathology. The main symptom of the disease is lameness, the severity of which depends on the severity of the pathology. In this case, the joint can retain its function, while the muscles of the thigh and buttocks gradually atrophy. If disturbances are observed in the distal sections, a lowering of the pelvis to the affected side is noted.

Typically, such a diagnosis requires surgical intervention, the main goal of which is to restore the length of the lower limb.

Hip dysplasia

With this disease, shortening of the legs and severe lameness are observed. When it affects both sides, the so-called duck gait appears.

Pathological changes in cases of such an anomaly include a decrease in the size of the femoral head and its displacement relative to the acetabulum.

At an early age, pathology can be eliminated with conservative treatment methods, which include the use of orthopedic splints and pillows. After the age of three, treatment of dysplasia requires surgery and subsequent long rehabilitation.

Typically, the pathology is caused by ossification of the femoral neck or damage to the fetal cartilage. Almost a third of cases of this disease are bilateral deformities.

This disease is characterized by significant limitation of movements of the lower limb and severe lameness. As a rule, surgical intervention is necessary for such pathology.

Also found hallux valgus, however, it is diagnosed very rarely. This is due to the fact that this pathology is asymptomatic.

In most cases, such pathologies are detected already during an X-ray examination and do not require additional diagnostic methods. Treatment methods in each specific case should be determined by a specialist.