Approximate weight of the fetus. Estimated fetal weight based on formulas and ultrasound data

For a wedding
22.08.2019

Needless to say, pregnancy is a very important and exciting event in the life of every woman. The anxious anticipation of the birth of a baby is sometimes replaced by anxiety and worry about whether it is developing correctly in the womb. For anyone expectant mother The main question remains: is everything okay with her child?

Not out of curiosity

It is very important throughout pregnancy to monitor the main parameters of the baby’s development and know how to calculate the weight and height of the fetus, what their timing is. This is necessary in order to have a complete picture of the health of the unborn baby.

Until the eighth week, the fetus is very small, its weight barely reaches one gram. Therefore, it is impossible to monitor the weight of the unborn child before this period, and it does not make sense. Then its weight increases very quickly, almost doubling, as the formation of the main organs occurs.

By the 15th week, the fetal brain is formed and the development of certain motor functions begins. Weight gain during this period is slower. And already from 28-32 weeks the baby begins to actively gain weight. There is a comprehensive growth of the child’s organs and systems, the formation of his reflexes and sensitivity.

Today, every pregnant woman has the opportunity to calculate the weight of the fetus by week. In addition to the usual arithmetic calculations of the baby’s weight and height, automatic calculation methods also come to the rescue.

Together with other indicators, weight will allow you to understand how the baby is developing and whether the fetus has any serious pathologies.

How to calculate the estimated weight of the fetus?

IN modern obstetrics apply different methods determining the weight of the baby in the womb - using several formulas and ultrasound examination. IN mandatory needs to be calculated approximate weight fetus in the last weeks of pregnancy in order to determine delivery tactics.

When calculating weight using formulas, certain parameters obtained from measurement and weighing are used expectant mother. According to the methods of Yakubova and Zhordania, the calculation is made according to the circumference of the abdomen and the height of the uterine fundus. The Bublichenko and Lankowitz formulas use the weight and height of the pregnant woman. How to calculate the weight of the fetus before childbirth, in each specific case determined by the doctor.

It should be remembered that the relationship between the parameters in the formulas was established through clinical and statistical studies. And the results obtained during the calculations depend on many individual factors and are of an average nature.

Calculate fetal weight using ultrasound

Ultrasound examination is a rather responsible and complex diagnostic method, with the help of which the gestational age is clarified and monitored. intrauterine development the fetus in accordance with physiological norms, the sex of the child is determined. During the entire pregnancy, 3 scheduled ultrasounds are performed.

The first study is scheduled at 12 weeks, then in the second and third trimester. Diagnostics during these periods helps to timely diagnose abnormalities in fetal development and take the necessary measures to eliminate the defects. Ultrasound allows you to most accurately calculate the approximate weight of the fetus, since in this case the weight of the uterus and amniotic fluid is not taken into account.

Modern ultrasound machines are already equipped with calculation programs that take into account even the smallest details research. However, this is only an approximate value; the exact weight of the child can only be known after his birth.

We calculate fetal weight using ultrasound data ourselves

1. According to Shepard:

Log(10) Fetal weight = -1.7492 + 0.166*(BPR) + 0.046*(FB) - (2.646*(FB+BPR)) / 1000.

2. According to Hadlock:

Log(10) Fetal weight = 1.3596 + 0.0064*(OG) + 0.0424*(CO) + 0.174*(DB) + 0.00061*(BPR)*(CO) - 0.00386*( Coolant)*(DB).

The examination data in the protocol is indicated in millimeters; it is important to convert it to centimeters.

BDP (in the ultrasound protocol indicated as BPD) - biparietal head diameter (the distance between the most distant points of the fetal head).

The coolant (in the ultrasound protocol - AC) is the circumference of the fetal abdomen.

OG (HC) - fetal head circumference.

DB (FL) - length femur.

But even in this case possible deviations The child's actual weight is 200-300 grams.

Normal fetal weight

Range normal values the mass of newborns is quite wide: minimum indicator not lower than 2.5 kg, and maximum – not higher than 4.0 kg. Low weight children are born in case of placental insufficiency, when the placenta for some reason could not cope with its functions. Also, a premature baby may be born weighing less than 2.5 kg if it deviates from the normal course of pregnancy.

Large children weighing more than 4.0 kg are at risk of obesity and diabetes mellitus even in the newborn period. Their health requires close attention and in adulthood. In both cases, the child’s weight is not last influence have hereditary factors.

Knowing how to calculate the weight of the fetus allows the expectant mother to independently monitor the baby’s weight in order to promptly eliminate deviations in fetal weight from normal values. If small or too heavy weight threatens problems for the child, the doctor will immediately warn you about this. The most important thing is not to worry prematurely.

The choice of obstetric tactics depending on fetal weight

How to calculate the weight of the fetus is half the question. The most important thing is to determine which method of delivery to choose. If the approximate weight of the child is within the normal range or less, this allows birth through the birth canal.

When the baby's estimated weight is more than 5.0 kg, this is an indication for a planned cesarean section. Although there have been cases where such large children were born naturally with a favorable outcome. If the child’s weight is between 4.0 kg and 5.0 kg, then it is necessary individual approach to the situation. The decision must be made by the doctor, taking into account the woman’s height, the size of her pelvis and other factors.

Thus, fetal weight is of great importance in determining obstetric tactics carrying out childbirth.

Let's sum it up

It's no secret that the health of a child depends entirely on the mental balance and health of the mother. In order for a mother to worry less about her baby, she must be sure that his development is proceeding normally.

Therefore, it is extremely important for her to determine how to calculate the weight of the fetus, which method of calculation is more reliable. Thanks to state-of-the-art equipment, calculating mass using ultrasound is the most precise method. Today, such an examination is quite accessible and has many advantages.

The most important thing is not to worry about trifles. And may you have a healthy and strong baby!

The normal weight of an unborn child is a problem that interests many expectant mothers. For some, it’s pure curiosity - what weight will my baby be? For others, it is important that everything is normal, that development goes according to plan. In any case, despite the fact that the child is in the womb and cannot simply be put on the scale, separated from the mother’s body, find out approximate weight It’s quite possible and you can do it at home.

The most popular ways to predict fetal weight

There are several ways to calculate the weight of the fetus and the weight of the unborn child. They are named after the inventors:

  • Lankowitz;
  • Bublichenko;
  • Yakubova;
  • Jordania;
  • as well as using ultrasound.

In order to use the formulas of these scientists, you need to have some information about your body:

  • own weight;
  • height of the uterine fundus;
  • abdominal circumference;
  • pregnant woman's height.

In the case of determining weight using ultrasound indicators, the doctor makes calculations based on already known data on the relationship between gestational age, linear characteristics of the fetus and weight.

Basic formulas for calculating fetal weight

All formulas by which it is customary to determine the approximate weight of the fetus were derived experimentally and have a high degree of accuracy, but in order for them to be as reliable as possible, many factors must be taken into account.

  • Lankowitz formula: we sum up the circumference of the uterus and the height of its fundus (in cm), as well as the weight (in kg) and height (in cm) of the woman and multiply the result by 10 - the result is quite accurate.
  • Yakubova’s formula: sum the uterine circumference and standing height and multiply the resulting value by 25.
  • According to Jordania, they calculate the product of the circumference of the uterus and its standing height.
  • Most simple formula Bublichenko: the weight of the expectant mother is divided by 20.


How to correctly measure the main indicators for calculating fetal weight

First of all, you need scales and tape measure. The circumference of the abdomen (uterus) is measured at the level of the navel, and the height of the fundus is determined as shown in the figure below. But it must be taken into account that some factors significantly distort the results. They are deftly recognized by an experienced professional, but can be missed by an amateur (a pregnant woman). So, the results will be inaccurate if:

  • twins are pregnant;
  • there is a lot of subcutaneous fat;
  • too much intrauterine fluid (or too little);
  • suspect the presence of fetal growth retardation syndrome, etc.

If there are no problems mentioned above, the woman may well be able to calculate the child’s weight at home, but in other cases it is better to ask the supervising doctor about this.


How to interpret the results

By calculating the expected weight of the child, you can understand how normal the pregnancy is. The normal range is 2500-4000 g. If the weight is below normal, intrauterine malnutrition is suspected when the placenta does not work enough. And if a pregnant woman is overweight, she should urgently adjust her weight and be monitored both herself and with the child, since giant children high risk various diseases type of diabetes.


The meaning of fetal weight for the obstetrician

They calculate the weight of the unborn child for a reason - it is very important for the future obstetric practice. When sharp deviation predicted results from the norm, doctors advise planning C-section, and there are several reasons for this:

  • a premature baby may be too weak, so his birth should be made as simple as possible for him;
  • a giant child may suffer from certain metabolic diseases from birth, so a cesarean section is also indicated for him;
  • When large children are born, the likelihood of their congenital injuries is too high, as well as more negative consequences for the mother herself.


So, the child’s weight should be calculated not only out of idle curiosity, but also for diagnosis normal development fetus, as well as birth planning. This can be done at home, which is not difficult for any mother, but will protect you from possible risks.

And examination of the woman must determine the weight of the fetus. This not only gives a certain idea of ​​​​the development of the fetus, but also allows you to determine one or another delivery tactics.

When determining the weight of the fetus, errors and inaccuracies are possible, since one or another formula is calculated based on the body parameters of the mother and fetus and depends on many factors. Sometimes several methods of determining fetal weight are used at once to increase accuracy.

Fetal weight begins to be determined at the earliest stages. This parameter is included in the list of necessary ones along with body length, head size, etc. Body weight is an indicator of normal child development.

The estimated fetal weight is determined by obstetricians. You can also determine the mass yourself, but you should take into account the high error. Even experienced doctors The weight of the fetus is not always determined accurately and after birth it turns out that the baby’s weight is more or less than expected.

Determination of fetal weight is carried out several times during pregnancy for the following purposes:

  1. Definition good nutrition mother. The development of the fetus directly depends on the mother’s diet, her nutrition, and the intake of vitamins in the body. The worse the mother eats, the less nutrition the child receives; he begins to take what he needs from the mother’s body. In this case, the woman’s teeth and hair begin to fall out, her immunity is impaired, and the fetus gains weight more slowly than expected.
  2. Detection of abnormalities in fetal development. If the fetus has any abnormalities, its weight will most likely be below normal. This gives the doctor a signal to further examine the mother and fetus, identify various disorders and hereditary diseases.
  3. Detection of frozen pregnancy. A frozen pregnancy is often diagnosed by the size and weight of the fetus and the size of the uterus. If the weight of the fetus is below normal, the doctor will suspect a frozen pregnancy. It is dangerous to a woman’s life and requires immediate delivery or early abortion.
  4. Choice of natural or artificial birth. Depending on the weight of the fetus, a decision is made about what kind of birth a woman will have. Very large fruit often requires elective caesarean section. A fetus with a weight below normal usually has pathologies and disorders, which is also dangerous during natural childbirth.
  5. Determination of maternal lifestyle adjustments. If a pregnant woman lives in an area with high air pollution, works at hazardous production, smokes or abuses alcohol, fetal weight is below normal. Doctors recommend that you be examined in a hospital and change your lifestyle.

Determination of the estimated fetal weight using formulas

There are several different formulas for determining fetal weight. All of them determine only the estimated mass and do not exclude a certain error, which can range from 10 to 20%.

Each formula requires knowledge of certain parameters. Usually this is the weight and height of the woman herself, the circumference of her abdomen and the height of the uterine fundus.

The accuracy of calculations largely depends on the correctness of measurements, so it is better to trust such things to doctors:

  • According to Lankowitz. According to this formula, you need to add the circumference of the woman’s abdomen, the height of the uterine fundus, the mother’s height in cm and her weight in this moment. The resulting amount is multiplied by 10 and the approximate weight of the fetus is obtained. This formula is quite accurate, but there is a slight error. In approximately 42% of the women studied, the fetal weight was determined with an error (from 500 g to 1 kg).
  • According to Johnson. Johnson's formula is a little more simple. Here you only need to know the height of the fundus of the uterus. From the resulting figure you need to subtract 11 (if the woman’s weight at the time of calculation is more than 90 kg, then multiply by 12), and then multiply the result by 155. This formula also has errors, since the height and specific weight of the mother is not taken into account, and there is also a high probability incorrect height determination.
  • According to Jordania. According to this formula, it is enough to multiply the girth of the woman’s abdomen (measured at the navel line) and the height of the uterine fundus. All measurements are in cm. This will be the approximate weight of the child.
  • According to Yakubova. The girth of the abdomen is taken, added to the height of the uterus, the result is divided by 4, and then multiplied by 100.
  • According to Stroikova. According to this formula, you need to get 2 numbers. The first number is obtained by dividing a woman's weight by a certain factor. For women with body weight below 50 kg it is 15, 51-53 kg - 16, 54-56 kg - 17, etc. The second number is obtained by multiplying the abdominal circumference by the height of the uterus. In terms of accuracy, this formula is slightly inferior to the Lankowitz formula.

The height of the uterine fundus must be determined by a doctor, since with independent measurement the probability of error is too high. The height of the uterus is determined only when the bladder is empty.

Determination of fetal weight using ultrasound data

With help you can do the most accurate calculations fetal weight. The device calculates the mass with great accuracy, but errors are still possible, although the possibility of error is reduced compared to calculations based on the mother's parameters.

The ultrasound procedure is performed several times during pregnancy. For each ultrasound, a specific protocol is drawn up that allows you to determine the child’s weight. This information is especially important before childbirth, when the weight of the fetus greatly affects the process of delivery.

To determine the weight of the fetus, the following ultrasound parameters are used:

  1. Gestational age. Sometimes obstetric term and the term according to ultrasound differ, but ultrasound is considered a more accurate procedure for determining the gestational age. It is the correspondence of body size to the gestational age that makes it possible to determine a large or low-weight fetus.
  2. BPR heads. The biparietal size is the width of the fetal head, that is, the distance between the temples. However, this parameter plays a decisive role only in the 1st and 2nd trimesters. Starting from the 28th week, BDP is determined by ultrasound, but the gestational age is not determined using this parameter.
  3. LZR. The fronto-occipital size is determined along the line opposite the BPR. These two parameters together give an accurate idea of ​​the size of the child's head. Both of these indicators make up the cephalic index, with which you can not only determine weight, but also identify developmental pathologies.
  4. The circumference of the baby's abdomen. The abdominal circumference is determined along the line of the umbilical vein and the child's liver. Using this parameter it is impossible to determine the gestational age, but to identify pathologies.

Fetometry allows you to determine the weight of a child without taking into account the amount of amniotic fluid and other factors that can increase errors in calculating the formula. However, the weight of the child is still approximate, since it largely depends on heredity. The child gains weight most actively during last weeks before giving birth, so the weight may differ from the expected one.

Deviation from the norm

For a normal pregnancy and a successful birth, the baby’s weight is very important. Using various formulas and fetometry, not only the weight of the fetus at a given moment is determined, but also its estimated weight at birth.

Normally, a child at birth should weigh from 2.5 to 4 kg. Deviations from the norm in any direction indicate the presence of any pregnancy pathologies. The fastest growth in fetal weight is observed in last trimester, starting from 30 weeks. The gestational age at the time of birth is also important. Childbirth from 38 to 42 weeks is considered within normal limits.

If, even during pregnancy, doctors note too rapid or slow growth in the weight of the fetus, the doctor will warn about the possible consequences.

What is dangerous about deviation of fetal weight from the norm:

  • A large fruit can lead to premature birth. Fast growth the child's weight is not an indicator have a safe pregnancy. The greater the deviation from the norm, the greater the likelihood that labor will begin ahead of schedule.
  • A large fetus is an indication for a planned cesarean section. Natural childbirth in this case may be too traumatic for mother and child if the size of the child's head and the mother's pelvis do not correspond to each other.
  • A low-weight fetus may indicate developmental pathologies, hereditary diseases, etc. The woman is further examined and the ultrasound is repeated several times.
  • Lack of weight may also indicate fetoplacental insufficiency. If a child does not have enough nutrients supplied through, he gains weight more slowly.

Useful video: how to find out a baby’s weight before birth

With a low-weight fetus, they also say malnutrition, but at the same time determine its type. If the fetus is completely symmetrically small, then they speak of insufficient nutrition, wrong term pregnancy or other pathology. If the child’s head size corresponds to the norm, and internal organs are not sufficiently developed, the cause of this condition may be the mother’s poor lifestyle (smoking, alcohol) or an intrauterine infection.

During pregnancy, most deviations from the norm are corrected. Therefore, women are advised to listen to the doctor and not refuse hospitalization.

Fetal weight is an important indicator of its development. This criterion is included in the list of diagnostic parameters, on the basis of which the doctor makes a conclusion about the course of pregnancy, the presence or absence of abnormalities, and prescribes appropriate examinations. The baby's development occurs quite quickly. This is facilitated by the enlargement of the uterus, the size of which increases 500 times during the gestation period. The weight of this organ at the last stage of pregnancy reaches 1 kg 200 g, despite the fact that its initial weight is 50 g.

The baby's weight is monitored using ultrasound. This diagnostic carried out from the middle of the first trimester. The size of the embryo, which is still too small to be seen even by an ultrasound machine, does not allow this procedure to be carried out at an earlier stage. At different stages of pregnancy, the fetus gains up to several hundred grams. Let's look at this process in more detail:

  1. On the 14th day of the cycle, a mature egg moves from the ovary to fallopian tube. Over the next 24 hours, she retains the ability to fertilize. If contact with a sperm occurs during this time period, the egg will be fertilized. Next, division will begin and on the fourth day it will move into the uterine cavity.
  2. After 3 weeks, the egg is implanted, this moment is considered the onset of conception. The outer cells of the embryo have villi, which attach it to blood vessels women. This is how the placenta is formed. The internal cells will subsequently form tissues and organs. The length of the embryo at this stage is 6 mm. It is located in a bladder that is filled with liquid.
  3. From 5 to 6 weeks, the formation of the spine, nervous system and brain occurs. The development of the digestive system, mouth, chest. By the end of the 6th week, the heart begins its work, in which 4 sections function. In the head area, 4 depressions are formed, which will later turn into ears and eyes. The formation of the circulatory system occurs. The embryo develops 4 formations from which limbs will form.
  4. With the onset of the 7th week, the length of the unborn baby reaches 13 mm. His head has already been formed, but so far it has disproportionately large parameters in relation to the body. You can make out a face. Fingers begin to appear on the limbs. At this stage, cells are formed from which the skeleton will develop. Central nervous system fully formed. There are internal organs, but their development is not yet complete.
  5. With the arrival of the 8th week, the length of the fetus is 2.5 cm. The main organs have already completed their formation. The outlines of the mouth and nose are visible on the face, and a tongue is formed. Increased size of arms and legs. The toes are fairly well marked, but there are still membranes between them.
  6. At week 12, the fetus increases to 65 mm, its weight is 18 g. You can see the ears on the head. The baby now has eyelids, allowing him to close his eyes. Marigolds are noticeable on the fingers. Muscle tissue develops, the child begins to move actively.
  7. From the 14th week, the placenta begins to perform one of its tasks and provides the fetus with nutrition. The head size is still disproportionately large. The neck is different. The body is covered with lanugo fluff. The baby has eyebrows and eyelashes. His bones become harder, and the joints of his limbs are formed. The degree of development of the genital organs allows one to determine gender. The child acquires the skill of thumb sucking.
  8. By week 16, the organs and systems of the fetus are formed. It reaches 16 cm in length and 135 g in weight.
  9. At 20 weeks of pregnancy, the weight of the fetus is 340 g, length - 25 cm. The child develops hairs and the base of teeth. Organs that have already formed increase in size. Kidney activity begins. The limbs acquire dimensions proportional to the body. The child is quite active. On at this stage Mom feels him well.
  10. In the period from 21 to 24 weeks, the baby weighs 570 g, his length is 33 cm. He acquires new skills and can already squint, frown, hiccup, cough, push, roll over, clench his fists. Appear in the skin sweat glands. The fetus has sufficiently developed auditory receptors. He is able to distinguish sounds, among which his mother’s voice and heartbeat stand out. The child spends a certain part of his time in a state of sleep. His tongue is already able to distinguish tastes.
  11. Until the 28th week, the baby gains 1 kg, his height reaches 37 cm. The formation of adipose tissue begins. The development of the cerebral cortex has completed. The lungs continue to form. The child is able to react to external stimuli and even cry.
  12. When the 30th week of pregnancy arrives, the fetus weighs about 1.5 kg and is 40 cm tall. At this stage, it is preparing for emergence and is in a suitable position.
  13. By week 36, the baby gains 2.5 kg and grows to 46 cm. Thanks to adipose tissue, he gains rounded shapes. Color skin turns pink. The baby has acquired a grasping reflex and can lift his head and turn. Lung formation is complete. The child has a reaction to light.
  14. By the 40th week, the baby’s weight is 3.4-3.5 kg, height – 50-51 cm. Vernix lubrication spreads throughout the body. The head descends into the pelvic area. It should be noted that these parameters are relative. Each pregnancy must be considered individually.

What determines the weight and height of the fetus by week of pregnancy?

Several factors influence fetal weight. One of them is the mother’s health status and her diet. Full growth of the baby is possible only with optimal insulin concentration. This substance promotes the formation of the fat layer, as well as all cells and tissues. If there is an excessive content of this element in the mother’s body, the child is born with a large weight. This mainly applies to women suffering from diabetes.

Anemia during pregnancy causes placental insufficiency. This can lead to developmental delays and the birth of an underweight baby. At 34 weeks of pregnancy, the normal weight of the fetus should reach 2150 g. If the baby weighs less, the doctor may suspect developmental abnormalities. But to confirm or refute this, it is necessary to conduct a certain examination.

The size of the fetus also depends on the condition of the placenta. Its growth is influenced by uteroplacental blood flow. If the function of this organ is impaired, the fetus is not provided with sufficient quantity nutrients and oxygen. As a result, the process of weight gain and growth slows down.
Disturbances in the condition of the placenta or in the health of the expectant mother do not always negatively affect the child’s body weight. With adequate therapy, the fetus develops according to established standards. If the baby’s weight is less than the required value, but no abnormalities are observed, treatment is not prescribed.

One of the factors influencing growth is heredity. The term “constitutionally low birth weight fetus” is applied to such children. If parents have thin build And short stature(up to 160 cm), light weight the baby is physiological in nature. Such a child has no pathologies.
But if underweight is due to any disorder, the woman should remain under the careful supervision of specialists. With placental insufficiency, developmental delay (hypotrophy) is observed. There are two types of this condition:

  • symmetrical;
  • asymmetrical hypotrophy.

In the first case, all organs lag behind in development, in the second, certain organs correspond to the deadline, while others lag behind in development.

The child’s weight is also influenced by such factors as: heredity, the woman’s lifestyle, the number of fetuses, various features pregnancy and maternal age. Women under 18 and over 35 years old require special monitoring. They are most often diagnosed with child malnutrition. When 36 weeks of pregnancy approaches, the weight of the fetus is 2.5 kg, height 45-46 cm. If the baby appears with these parameters before a certain period, he is considered full-term and fully ready for life outside the mother’s womb.
If the placenta does not fulfill its function, the expectant mother is prescribed vasodilating medications, the action of which is aimed at normalizing the blood supply to the blood vessels of the fetus and uterus. And also apply medicines, which increase the child’s resistance to oxygen deficiency.

Exceeding the weight limit

Exceeding the norm also does not always indicate the presence of anomalies. Excessive baby weight, which is 4 kg or more, can be explained by the large physique of the parents or the mother’s excess nutrition. If a woman is diagnosed diabetes or other deviations endocrine system a large weight of the child should be considered as a complication. This situation can also arise as a result of postmaturity. If at 35 weeks of pregnancy the weight of the fetus exceeds 2390 g, it can be said that the baby will appear large.
The baby's heavy weight complicates the delivery process. If his head exceeds the size of the woman's pelvis, the doctor may decide to perform a caesarean section. Too much big sizes cause premature discharge amniotic fluid and weak labor activity.

Home methods for calculating weight

You can determine the baby’s weight yourself at home. There are several options for this:

  1. One of them involves multiplying the abdominal circumference by the height of the uterine fundus. It must be taken into account that the result may be affected by the amount of amniotic fluid, the position of the fetus in the uterine cavity, and its physique. But despite this this method is considered to be the most reliable.
  2. According to next method you need to divide the abdominal circumference by the height of the uterine fundus. The result should be divided by 4 more and multiplied by 100. This option not primarily used as independent method calculation, but is used to confirm existing indicators.
  3. You can also determine the weight of the fetus using the Solovyov method. Its peculiarity is that the size of the mother’s wrist and her physique are taken into account. This method may seem unreliable; some women have doubts about the ability to calculate a child’s weight from the wrist. But at the same time it gives true results.

First of all, you need to determine the index. If the wrist of the expectant mother has a circumference greater than 16 cm, the index value will be 12. If the circumference is less than 16 cm, this indicator will be 11. Next, the index is subtracted from the height of the uterine fundus, the resulting number is multiplied by 155. At 31 weeks of pregnancy, the weight of the fetus should reach 1.5 kg. The Solovyov measurement method will help you check how much the baby’s mass corresponds to this parameter. To get the maximum reliable results It is recommended to determine weight using all three methods.

Weight determination by ultrasound

IN medical institution fetal weight is determined by ultrasound diagnostics. The doctor focuses on the following indicators:

  • gestational age;
  • biparietal parameters of the head (the space between the two widest areas);
  • length of arms and legs;
  • fronto-occipital parameters;
  • abdominal and head circumference.

If abnormalities are detected, to clarify the diagnosis, a Doppler study of the baby’s blood vessels, placenta and umbilical cord is prescribed, which allows one to get an idea of ​​the speed of blood flow. Cardiotocography is also necessary.

Based on the results this study The doctor monitors the fetal heartbeat as a response to uterine contractions. For example, the weight of the fetus at the 33rd week of pregnancy should reach 1900. If there is a lag from this norm, this is an indication for additional research.

Fetal weight by week of pregnancy: table

Conclusion

Tracking fetal weight is one of the main procedures during pregnancy. Based on the baby’s parameters, one can judge his development. And also promptly detect deviations if they occur. But you should not immediately worry if the doctor says that the child is underweight or, on the contrary, exceeds the norm. Similar phenomena may arise as a result of heredity or characteristics of pregnancy. Each case should be considered individually. And if disturbances in the development of the child are detected, the use medications will help normalize the condition and a healthy baby will appear at the appointed time.
Video: fetal development by week

During scheduled visits During pregnancy, a gynecologist must weigh a woman and measure the girth of her abdomen in order to know how the child grows and develops. One of the main characteristics that the doctor records is the weight of the fetus by week of pregnancy, its size and the length of the skull circumference. All these indicators are important in order to assess the baby’s health, its development, and to notice the onset of the disease in time if it suddenly happens. It is especially important to calculate fetal weight by week of pregnancy. later, before childbirth, since the time and method of birth often depends on the size of the child.

Equally important is regular examinations of mother and child in the first months of a woman’s pregnancy. During this period, all systems and organs in the baby’s body are formed, the placenta and umbilical cord are being formed, and therefore doctors carefully monitor the condition of the embryo. In the first months of pregnancy, the weight of the fetus is very small, and therefore doctors measure only the weight of the mother, and the child is examined and measured using ultrasound.

The values ​​given in the tables below are approximate averages. The weight and size of the embryo by week and month depends on the constitution of the mother and father of the child, on hereditary factors, the rhythm of life and the mother’s diet during pregnancy, and hereditary diseases. Only a doctor can say for sure that a child is developing normally or not normally, after studying the data from several examinations, ultrasounds and tests of the mother, her medical history and medical record.

In later stages, the weight and other indicators of the embryo may differ from normal to a greater or lesser extent. The intrauterine development of a child depends entirely on the mother’s lifestyle, and if the mother does not eat well, abuses sweets or fast food, then the baby can also gain weight faster than necessary. At multiple pregnancy The weight of each baby is usually less than with a standard singleton.

Fetal weight and size by week of pregnancy in the first trimester

First screening – full examination women and baby - usually carried out at 10-13 weeks of pregnancy. Usually during this period women are convinced that they are pregnant and register with antenatal clinic, where the study is carried out and the course of pregnancy is observed. The weight of the fetus during this period of time ranges from 4 grams at 10 weeks to 25 grams at 13, and most of the space in the uterus is occupied amniotic fluid. The doctor receives basic information from a blood test and measuring the size of the embryo using ultrasound.

The size of the embryo by week in the first trimester should be as follows:


If the weight or size of the embryo differs slightly from the average, do not be alarmed. Most often this is due to incorrect definition pregnancy, and since the baby gains several grams every day, small discrepancies are acceptable.

The gestation period can be calculated obstetric weeks, that is, counted from the date last menstrual period, or measured from the date of conception. In the first case, it is believed that pregnancy occurred 2-3 weeks earlier, in the second the error will be only a few days. Due to inaccurate calculation of gestational age normal indicators may move to one side or the other.

At the first screening, the doctor evaluates not only the weight and size of the fetus by week of pregnancy, but also measures the length of some of the baby’s bones. Be sure to take into account:

  • The size and length of the femur shows how correctly the skeleton is developing. At the age of 12 weeks, the embryo has a fully formed skeleton and all the bones are laid, which will only increase in size further. Using an ultrasound, the doctor looks at how correctly the skeleton is developed, how the length of the femur correlates with the size of the spine, shoulder, tibia and radius bones;
  • The size of the chest also shows the presence of pathologies in the development of the baby and the correct formation of internal organs. The chest circumference should be proportional to the growth of the embryo. Some studies do not calculate the circumference of the chest, but its diameter;
  • Biparental head size (BHR), that is, the width of the skull in a straight line from temple to temple, is one of the most important indicators normal development. The size of the head shows how well the child’s brain and the bones of his skull are developing, and going beyond the normal range may indicate Down syndrome and several similar diseases, anencephaly, hydrocephalus and other pathologies that serve as a reason for termination of pregnancy. In the later stages, the BPR is replaced by the fronto-occipital size;
  • The growth of the embryo is calculated by the size of the spine, from the crown of the embryo to the tailbone, and the length of the legs is not taken into account. The size of the fetus changes over the weeks of pregnancy, but the baby always develops strictly in proportion. Therefore, if all parameters except one are normal, then we can talk about pathology in the child’s development.
  • In addition to the growth of the embryo, doctors in the first trimester measure and compare the size of the fertilized egg and the child’s heart rate with the norm. Using these indicators, you can much more accurately determine the age of the embryo and its state of health.

Fetal size by week of pregnancy in the second trimester


In the second trimester, during the second screening, the baby in the mother's womb has grown enough to be able to see its face, fingers and toes, and all internal organs. The second screening is aimed at how much the child has grown, his weight and height, the structure of the face and head, the maturity of the lungs and the structure of all internal organs.

Fetal weight and size by week of pregnancy in the second trimester:


Other parameters, such as the girth of the skull and chest, the length of the bones of the legs and arms, are also recorded during screening and ultrasound diagnostics, but they are not as important as in the first trimester. Usually the second full research carried out at 17-18 weeks of pregnancy, when the weight of the fetus in the womb has increased so much that the child can be fully examined. Typically, a second study is prescribed if it is necessary to confirm or refute information obtained in the first trimester, to track the dynamics of pregnancy, and to verify the presence or absence of pathologies.

A second screening is considered unnecessary if the woman is healthy and healthy image life, she is less than 35 years old, all her children were born healthy and the pregnancy is developing normally. But you can go through this study by at will in a public or private clinic.

Third trimester: fetal weight by week

During pregnancy, the weight of the fetus changes over the weeks and months, and by the third trimester, the baby in the mother's womb turns from an embryo into a baby ready to be born. The third screening, unlike the second, is important for normal management pregnancy and preparation for childbirth, and based on its result, the doctor can either prescribe a cesarean section for the mother or allow natural childbirth, and in the case poor prognosis a woman may be admitted to the hospital “for safekeeping.”

During the ultrasound diagnostic process during the third screening, doctors look at the size of the embryo by week and day from the crown to the sacrum, the weight of the child, the degree of development and girth of the skull.

Fetal weight by week of pregnancy in the third trimester:


During the third screening, doctors diagnose a number of diseases and malformations that the child may suffer from, assess the condition of the umbilical cord, uterus, size and condition of the placenta. Normal term screening - around 30-34 weeks, when the baby is actively gaining centimeters of height and grams of weight. Often, along with ultrasound diagnostics, Doppler measurements are performed to assess the movement of blood through the vessels and CTG to listen to the rhythm of the child’s heart. Sometimes the dates of the study are shifted to a later date.