When does the belly start to grow during pregnancy?

One of the undeniable signs of pregnancy is an enlarged belly. Why and how does it grow? It would seem that the answer is obvious: the belly grows because the child is growing in it, and this happens in the same way for all expectant mothers, because any normal pregnancy lasts 9 months. In fact, everything is much more complicated, and the characteristics of abdominal growth during pregnancy can tell a specialist a lot...

What causes the belly to grow during pregnancy? Due to the growth of the fetus, uterus and an increase in the amount of amniotic fluid - the habitat of the unborn baby.

Let's talk in more detail about each of the listed components.

When does belly growth begin during pregnancy?

It is impossible to predict exactly at what stage of pregnancy the belly begins to grow.
But there are average values. In the early stages, the abdomen is usually invisible, since the uterus is small and does not extend beyond the pelvis. Around 12-16 weeks, you will notice that your clothes have become tighter. This happens because the uterus begins to grow and enlarge - the tummy rises beyond the pelvis. At 4–5 months, the doctor begins to measure the height of the uterine fundus. During this period, the growth of the abdomen during pregnancy becomes faster.

Fetal sizes by week

The size of first the fertilized egg and then the fetus is determined by the results of an ultrasound examination (ultrasound). With the help of transvaginal ultrasound (the sensor is inserted into the vagina during this study), the fertilized egg can be detected after 2-3 weeks of its development; the gestational age, which is counted from the first day of the last menstruation, is 6-7 weeks at this time. The diameter of the fertilized egg at this stage is 2-4 mm.

At the 8th week of development - 10th week of pregnancy, the diameter of the ovum reaches 22 mm.

At 12 weeks of pregnancy, the length of the fetus is 6-7 cm, body weight is 20-25 g. An ultrasound examination shows that the fertilized egg almost completely fills the uterine cavity.

By the end of the 16th week of pregnancy, the length of the fetus reaches 12 cm and body weight - 100 g.

At 20 weeks, the length of the fetus is already 25-26 cm, weight - 280-300 g.

At 24 weeks, the length of the fetus is about 30 cm, weight - 600-680 g.

At 28 weeks, the length of the fetus is 35 cm, body weight is 1000-1200 g.

At 32 weeks, the length of the fetus reaches 40-42 cm, body weight - 1500-1700 g.

At 36 weeks these figures are 45-48 cm and 2400-2500 g, respectively.

The body weight of a full-term fetus at the time of birth is 2600-5000 g, length - 48-54 cm.

If the dimensions are not correct

A significant slowdown in growth rates or, conversely, a strong advance may indicate pathology. Deviations from the norm are not yet a diagnosis, but they are already a reason to prescribe additional examination for the pregnant woman.

Often, a VDM lower than normal indicates an incorrectly set deadline. This happens in women with irregular menstruation, as well as in breastfeeding women. If everything is normal on ultrasound and Doppler, then the doctor can adjust the due date.

In the second and third trimester, the uterus may grow more slowly due to oligohydramnios or abnormal position of the fetus (oblique or transverse). If the UMR lags by more than 2 cm, the baby’s growth is likely to be delayed due to problems with the placenta, intrauterine infections, and insufficient nutrition of the mother. If the GMR norms are exceeded by more than 2–3 cm, a large fetus is possible. In any case, timely diagnosis is important in order to exclude complications and correct deviations in time.

When is it possible for the abdomen to grow earlier during pregnancy?

Abdominal enlargement at less than 12 weeks is likely due to several reasons:

• Twins. During multiple pregnancies, the belly begins to grow earlier. A woman also gains weight faster;
• Repeated pregnancy. The muscles are already stretched, and if they have not returned to their original size, the belly will be noticeable earlier;
• Bloating. In the first months, progesterone causes gastrointestinal activity and the belly may become somewhat distended;
• Narrow pelvis. The uterus quickly begins to become “crowded”, and it “moves” the muscles and internal organs;
• Polyhydramnios. An enlarged amniotic sac can affect the overall size of the abdomen.

It has been noticed that in slender women, abdominal growth begins earlier during pregnancy. Overweight people have more subcutaneous fat, and the increase in abdominal size is not as pronounced.

How does your belly grow?

Sooner or later it will become noticeable in all pregnant women. But why is it visible in some people already at 10-15 weeks, and in others after 20?

Size range

The rate at which the abdomen grows depends on how quickly the uterus enlarges. This is due to the amount of fetuses and amniotic fluid, the weight of the baby and the placenta. Normally, the volume of water is from 500 until the end of pregnancy reaches 500-600 g. Each new gram of the baby stretches the uterus, causing both it and the tummy to increase.

So, at the 16th week the baby’s weight is about 100 g, at 28 weeks - a little more than a kilogram. The average weight of a newborn is from 2700 to 4000 g.

Above normal

There are also real heroes - more than 5 kg. In August of this year, a boy weighing 6,700 g was born in Vladivostok by caesarean section. Obviously, the size of the belly of such a robust mother exceeded the established norms. But even pregnant women with a small, neat belly often give birth to absolutely healthy, full-term babies, not exceeding 2.5 kg. The genetic factor plays a significant role. Thin, short parents usually have medium-sized children.

Growth dynamics

During pregnancy, the uterus has a hard time. After all, in 40 weeks it should increase 15-20 times! Up to the “equator” it does not grow so intensively. At four obstetric weeks, its volume can be compared with a chicken egg, and at eight - with a goose egg. By the time of the first screening, the fundus of the uterus rises to the upper edge of the pubis, and in size it resembles the head of a newborn. After 20 weeks, rapid growth begins. If no one knew about your pregnancy before, now only loose clothes will cover your rounded figure. The bottom of the uterus - its highest point - is already at the level of the navel, becoming higher every week.

Time for new things

Starting from the second half of the term, doctors recommend wearing a bandage to reduce the load on the back. The usual trousers are tight, and the blouse does not meet at the waist. You will need special trousers with elastic and tights that will not tighten your stomach.

It is possible that you will have problems sleeping. It is increasingly difficult to find a comfortable position, and the lower back, tired during the day, does not relax. You can place additional pillows under your stomach and back, or use a special one for pregnant women.

The abdomen will reach its maximum size at 38 weeks, when the fundus of the uterus approaches the xiphoid process and costal arches. When the baby takes the starting position for childbirth - head down, the stomach will drop again. It will become much easier to breathe.

Subtle points

It is also necessary to take into account the presentation of the fetus. If it is cephalic, the belly is oval. If transverse, the shape is irregular or spherical. It is a common belief that with the second pregnancy the belly is noticeable earlier. But from a medical point of view, there are no differences in the rate of uterine growth between primiparous and multiparous women. It is likely that muscles that have not had time to recover after the first pregnancy sag and stretch faster under the pressure of the uterus. The physique of the expectant mother also plays a role. If before conception she was inclined to be overweight, then for a long time the changes in her figure are not visible not only to others, but even to herself. The tummy is the first to become visible in women of normal build.

Back or front

The volume of the pelvis also matters. If it is narrow, the abdomen appears larger because the fetal head rises too high. Often the timing of the appearance of the abdomen is associated with the placenta’s attachment to the uterus. If it is located at the back wall, the stomach will not soon begin to protrude forward: the uterus and the child feel comfortable among the internal organs. When the placenta is on the anterior wall, the “interesting position” is noticeable earlier. In both cases, the uterus grows the same way, it just puts more pressure on the muscles in the anterior attachment, stretching them.

Units

Most often, the expectant mother's worries about the rate of growth of the abdomen are unfounded: comparisons with other pregnant women or with their own reflection in the mirror a week ago are subjective. Nevertheless, there are criteria that the stomach must meet. And the gynecologist determines them. At each appointment, he records the height of the uterine fundus. It extends beyond the pelvic area from the 16th week. From this moment it can be felt through the abdominal wall.

Fundal height of the uterus (FHH) is the distance between the upper point of the pubic symphysis (in other words, the pubis) and the highest point of the uterus. It is measured with a regular measuring tape while lying on your back, legs straightened. The bladder should be empty. All indicators the doctor enters them into the exchange card each time in order to be able to compare and track them.

Important centimeters

The height of the uterine fundus in centimeters approximately coincides with the expected week of pregnancy. In the first half, it usually differs by 1-2 cm in a larger direction. So, at 16 weeks, the VSDM is 17-18 cm. “Extra” centimeters appear due to fat deposits on the abdomen. From the 20th week, VSDM is identical to the week of pregnancy. Of course, these are averages - a lot depends on your body type.

The main thing is the personal growth dynamics of VSDM. By childbirth, the abdominal circumference reaches almost 100 cm. But this parameter is also individual.

• Too small.

WSDM does not always correspond to the gestational age or does not change compared to previous measurements. This indicates oligohydramnios, low rates of fetal development, and its transverse or oblique position. The deadline may have been calculated incorrectly. To exclude developmental delay syndrome, it is necessary to perform an ultrasound, where the doctor looks at the ratio of the size of the fetus and the gestational age. After the 20th week, Doppler measurements are performed in parallel with ultrasound. What if the reason is poor nutrition due to impaired blood flow?

After the 30th week, cardiotocography is required to detect cardiac dysfunction. Insufficient growth of the uterus is often affected by oligohydramnios, when the amount of amniotic fluid is less than 0.5 liters. Unlike polyhydramnios, it usually accompanies pregnancy from the very beginning.

• Too big.

Inflated indicators of VSDM and abdominal circumference indicate polyhydramnios or a very large fetus. The latter is associated with diabetes. If the expectant mother has difficulty digesting glucose or has a metabolic disorder, excess glucose enters the baby’s bloodstream, and the baby grows faster.

If gynecologists suspect that a big belly is a consequence of banal overeating, they recommend a diet. Heredity cannot be ignored either: large parents often give birth to children weighing 4 kg or more.

• There is water all around.

The uterus also enlarges with polyhydramnios. It occurs with diabetes mellitus, Rh-conflict pregnancy, acute or chronic infection, and fetal development abnormalities. May interfere with the normal course of pregnancy, lead to fetal pathology or premature birth. As soon as an ultrasound reveals such a deviation, the expectant mother should be under close medical supervision. And yet, you should not immediately sound the alarm if the VSDM and abdominal circumference do not correspond to the gestational age. The measurement errors in this case are quite large, and only additional examinations and ultrasound, which will be prescribed to you by your obstetrician-gynecologist, will clarify the situation.

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Why does the figure change?

A woman’s body undergoes a serious restructuring, which affects the condition of the skin, hair and especially the figure. The main reasons for changes in appearance:

• Changes in hormonal levels. Under the influence of progesterone, the condition of the skin changes - a decrease in firmness and elasticity is possible;
• Gradual weight gain. The mass of the uterus, fetus, and amniotic fluid is added. Expectant mothers are getting better, at least a little;
• Abdominal growth during pregnancy. The sides “blur”, the figure becomes more rounded. Some have a miniature belly, others have a very large one;
• Breast augmentation. Estrogen and progesterone stimulate the development of milk ducts and glandular tissue. Breasts can grow several sizes, and their sensitivity increases greatly;
• Changes in posture. The center of gravity shifts, often causing pain and discomfort in the lower back. Pregnant women's gait changes. Some women instinctively straighten their shoulders and back;
• Load on the legs. An increase in overall pressure on the legs causes swelling and sometimes varicose veins. Visually, the shape of the feet and legs may look different.

All these changes affect the overall perception of the figure and appearance of the expectant mother. How pronounced the changes will be depends on the physique and size of the pelvis. Some people's stomachs become a little rounder, while others gain a lot of weight and get better overall. If a woman does not overeat and leads a healthy lifestyle, then all changes are easily reversible after childbirth.

Amniotic fluid

The increase in the volume of amniotic fluid (amniotic fluid) occurs unevenly. So, at 10 weeks of pregnancy their volume averages 30 ml, at 13-14 weeks - 100 ml, at 18 weeks - 400 ml, etc. The maximum volume is observed at 37-38 weeks (on average - 1000-1500 ml). By the end of pregnancy, the amount of water may decrease to 800 ml. During postterm pregnancy (at 41-42 weeks), a decrease in the volume of amniotic fluid is observed (less than 800 ml).

Belly shape

The growth of the abdomen during pregnancy, as well as its shape, depend on the woman’s physique and the size of the pelvis. Contrary to popular superstitions, a “sharp” shape does not indicate that there will be a boy, and a rounded one does not mean that it will be a girl. The same applies to twins - both same-sex and opposite-sex.

An enlarged tummy is a natural condition. Even in the early stages, it is forbidden to tighten it and wear tight clothes. Depending on the shape of the belly, you can choose suitable things - wide T-shirts, tunics, dresses and skirts with a semi-fitting or bell silhouette. The main thing is your comfort and the safety of your unborn baby.

What to do when you're ready to talk about your pregnancy

Only you have the right to decide when to tell others about this good news. You may want to talk about your pregnancy long before your baby bump is visible. Or you can wait until the rounded lines make your pregnancy a little more obvious.

Some expectant mothers report this news immediately after receiving the coveted confirmation of pregnancy. Others wait until the second trimester, when the likelihood of miscarriage is much lower. And there are those who prefer to go with the flow and act according to their feelings.

The moment when you tell about your pregnancy depends on who exactly you decide to share this good news with. For example, you can make your partner happy right away, but tell your colleagues about it later, after some time.

Tell us about your pregnancy when you feel ready to do so. You can even announce your pregnancy in an unusual way.

If the changes are not noticeable

Expectant mothers are worried if the growth of the abdomen during pregnancy is too slow or does not begin after 4-5 months. You shouldn’t worry right away, because the main thing is the dynamics of the height of the uterine fundus and the condition of the baby.

There are several reasons for not very active abdominal enlargement:

• Individual physiological characteristics. For example, with wide hips, there is more room in the pelvis for the uterus, and it can “come out” into the abdominal cavity later;
• Trained abs. In this case, the abdominal wall can retain its elastic shape longer;
• Low water. In this case, correction is required, since the condition is considered a complication;
• Heredity. If your mother or grandmother were miniature during pregnancy, you should not expect too big a belly;
• Excess weight. In plump women, the stomach becomes noticeable later, since it was not flat before conception. At the same time, the expectant mother herself may notice changes, but others around her may not.

Typically, growth peaks at 6–7 months. But even if this is not the case, draw the doctor’s attention to what worries you. Most situations, even pathological ones, can be treated and corrected. Have an easy pregnancy!

Why is it important to track belly size during gestation?

Abdominal circumference is a fairly important parameter during pregnancy. This measurement makes it possible to draw initial conclusions about the baby’s intrauterine development and suggest multiple births or a certain pathology.

Determination of abdominal circumference is usually carried out simultaneously with measurement of the height of the uterine fundus. According to the gestational age, these parameters should naturally increase.

In addition, using the indicated values, the gynecologist can guess the approximate weight of the fetus. There is a special formula for this purpose:

• FW * FWDM = fetal weight.
• OB is the circumference of the abdomen, and VSDM is the height of the uterine fundus.