Abdominal Changes During Pregnancy

Aug 23 2007

As pregnancy progresses, a woman is likely to become conscious of the gradual filling of her lower abdomen. At first she might notice that she is “losing” her waistline. Next, when her bladder is full, she may be able to feel a small, soft mass, just above the pubic bone (the bone felt behind the pubic hair). The bladder is simply pushing the pregnant uterus up to where it can be felt through the relaxed abdominal wall. The uterus gradually grows upward during the pregnancy, by 12 weeks reaching to where it can be felt above the pubic bone without a full bladder. It grows to the level of the navel or umbilicus at about 20 weeks.Most pregnant women begin to “show” at some time between 14 and 20 weeks, although this varies greatly from woman to woman. Some women look obviously pregnant at week 14 while wearing ordinary street clothes, and others wear tight blue jeans through the sixth month and barely look pregnant at all to the casual observer. As the size of the uterus increases, stretch marks or striae may appear. This common term is something of a misnomer. The marks are only partly due to the mechanical stress of the growing uterus on the skin, and connective tissue of the abdominal wall. They also result from the hormonal influences of pregnancy, and in fact appear in areas where there is no actual physical stretching. Above the navel they tend to look something like the upper half of a circle, around the navel they form a circular pattern, and in the lower abdomen they characteristically form lines slanting downward and inward. The marks are very slightly depressed below the level of the normal skin, making the skin look frayed.

Stretch marks may appear no matter how little weight a woman gains. Some women may have an inherited tendency toward developing them. They tend to increase as the pregnancy progresses, and have a red or brownish color from the growth of tiny blood vessels. After delivery they gradually fade as the blood vessels become less prominent. They become shiny and pearl white, and narrower than they were during pregnancy, but they do not entirely vanish. Abdominal Changes During Pregnancy

In some women, the navel begins to protrude during the latter months of pregnancy. Although completely normal, this may be embarrassing to some women in certain clothing. Covering the navel with a Band-Aid is usually comfortable and will prevent it from being seen as a protrusion beneath almost all clothing. The end of the sternum or breastbone, called the xiphoid, is attached by a hinged joint. Under ordinary circumstances, this bone cannot be felt, but in late pregnancy it may loosen up and rotate outward so that a bump can be felt in the V-shaped space between the lower margin of the ribs. This is quite normal.

The long muscles of the abdominal wall-the rectus abdominis which run from the rib cage down to the pubic bone are stretched by the growing uterus. As a result, in the later part of pregnancy, they separate in the midline of the abdomen. When the abdomen is filled with the pregnant uterus, this is not particularly noticeable, but as soon as the baby is delivered, separation of the rectus muscles-the diastases recti-may be quite obvious. Sometimes you can see or feel a vertical indentation in the middle of the abdomen, usually starting at or below the navel and going to the breastbone (sternum). If you can’t see this clearly, you can lie down and contract your abdominal muscles by lifting your chin. This will exaggerate the diastasis and you can more easily see or feel it. You can reduce the degree of separation with exercises for the stomach muscles but the muscles may never completely close. This usually is not a problem, but if the diastasis remains large, in subsequent pregnancies there may be less support for the growing uterus and sometimes extra discomfort as pregnancy progresses.

Quickening

Somewhere between 16 and 22 weeks, the mother is first able to feel the movements of the fetus. Fetal movements are felt more readily when the placenta is attached to the rear wall of the uterus. A woman having her first baby will probably notice the movements about 2 weeks farther along than she will in later pregnancies, when she may recognize them as early as the sixteenth week. Tell your midwife or physician when you first definitely feel the fetus move because this can help to time the pregnancy. The subjective sensation of these first movements has been likened poetically to the faint flutter of a caged bird’s wing and, more prosaically, to the bursting of a bubble of thick syrup.

At the onset the movement is so gentle, particularly since the baby is floating in an amount of water greater than its size, that the woman may not be certain what she has felt. Only after these light taps against her uterine wall have been repeated several times can she be certain that this is fetal movement. Of course, later in pregnancy, the movements of the arms and legs, the stretching of the trunk, and the movement of the baby’s head become very much more powerful, to the point where anyone is able to feel them by placing a hand on the mother’s abdominal wall. Often, fetal movements can be seen beneath the skin. Sometimes the movements are so active that women become convinced that they are carrying twins or triplets.

Once women perceive fetal movements they come to expect to feel them every day, but at the beginning, several days may pass when they are not felt at all. In later pregnancy, certainly by week 24, fetal movements are felt daily. Fetuses in general tend to be more active late in the day, after supper and stretching into bedtime, to the point where they may sometimes make it difficult for the woman to fall asleep.

Ultrasound examinations have confirmed that at quiet times the fetus is in fact asleep. In general, fetal cycles of sleeping and awakening tend to run on about a 90-minute schedule. In the third trimester, starting about week 26 of pregnancy, if a fetus goes more than 24 hours without activity, call your care provider immediately, since lack of movement may be a warning signal of fetal distress. A marked decrease in the number of fetal movements is also a reason to notify your physician or midwife.