The major physical changes that women experience during the second trimester include the following:
- The Uterus. The uterus begins to expand out of the pelvis and into the abdominal cavity by the fourteenth week. By the twentieth week, which is midway through the second trimester, the uterus is usually at the level of the navel. A woman pregnant for the first time usually begins to feel the movements of the uterus at about 16 to 18 weeks. Women who have already borne at least one tad often feel these movements earlier. When the movements are first perceived, seizes are about 7 inches long and weighs less than 1 pound. The woman may feel mild uterine contractions, called Braxton-Hicks contractions.
- Vagina. The tissues of the vagina continue to soften and become more elastic, preparing for the baby’s passage at birth.
- Pelvis. Hormones cause the cartilage to soften and widen to provide additional mobility and relaxation in the pelvic joints. This allows a large baby to pass through more easily.
- Breasts. Colostrum, a clear yellow fluid that precedes mature breast milk is often present by 16 weeks.
- Circulation. By the end of the second trimester, the blood volume has increased by 40 to 60 percent and the heart has begun pumping more blood per beat. Edema (swelling) is common because of the pressure from the enlarging uterus, and the increase in estrogen. The fluid will tend to pool in your feet and hands. Resting on your side will improve your circulation and will help to relieve the edema. Increasing your protein intake will help to decrease the swelling.
- The Linea Nigra. The linea nigra is a dark line that appears on the abdomen during pregnancy. It is common and is attributed to the hormonal activity of pregnancy. It occurs after delivery, although it may continue to be visible.
- Stretch Marks. Many women develop at least some stretch marks during pregnancy. Stretch marks appear when the connective tissue is stretched to the point of rupture. They are red or pink lines and may appear on the abdomen, thighs, or breasts. After delivery, they fade to white. By massaging oil or lotion into the vulnerable areas prevents stretch marks although heredity seems to be a more important factor.