Pregnancy 31 weeks:The ultrasound shows that at this stage of pregnancy the fetus continues to grow and develop, it has already mastered sucking. At this stage, the baby's kidneys are already working well, but urine is still excreted into the amniotic fluid. About 500 ml of blood now passes through the uterine circulatory system, which is in close contact with the placental circulatory system. At the same time, the blood of the expectant mother never mixes with the baby's blood. This happens due to a thin partition - the dividing placental barrier. The skin of the fetus at this stage of pregnancy takes on a pink color, white fatty tissue begins to be deposited under it. Therefore, the blood vessels are no longer visible through it. The nails on the arms and legs reach the fingertips. The child's pupils, almost like those of an adult, begin to react not only to light, but also to darkness. Your baby already weighs about 1600 g, its length from the crown to the sacrum is about 28 centimeters. Pregnancy 31 weeks - symptoms for mom: At this stage of pregnancy, back pain is almost inevitable. The thing is that the muscles and ligaments of the back are now in a relaxed state, resting, preparing for the birth process. At this stage, pregnant women have a high probability of varicose veins in the legs. Pregnancy 31 weeks - signs: During the entire previous period of pregnancy, a woman, as a rule, gains about 8.5 kilograms of excess weight, which consists of the weight of the fetus itself, the enlarged uterus, amniotic fluid and placenta, including the total amount of blood in the vessels. At this stage, the abdomen continues to increase in volume. Unpleasant sensations in the pelvic area and chest may bother you. This happens because your growing baby requires more and more space. The uterus, increasing in size, displaces other internal organs from their usual places, thereby creating some difficulties for the normal functioning of the stomach. This is why some women begin to worry about heartburn. Therefore, fractional nutrition is recommended. At this stage, the woman's body begins to produce relaxin, a special hormone that causes the connective tissue of the pelvic bones to weaken. As a result, the mother's pelvic ring becomes more elastic and flexible. Thanks to this, the child experiences fewer difficulties during birth.