As the baby and uterus grow, from about 12-14 weeks of gestation, the tummy begins to grow and becomes somewhat denser, and the following internal changes occur:
• the cervix becomes bluish;
• the cervix descends, its canal closes;
• the endometrial layer thickens;
• the uterus becomes easily excitable (Snegirev's symptom);
• the uterus takes on the appearance of an asymmetrical ball, which increases transversely;
• the structure of the uterus loosens and becomes soft.
The gradual enlargement of the uterus leads to growth of the abdomen, which should occur gradually and be regularly measured by a doctor.
In a normal state, the abdomen should be soft, but if, when palpated, it seems hard, like a soccer ball, then this indicates increased uterine tone, which can pose a threat to the baby’s health and cause miscarriage or premature birth.
Sometimes in the early stages, a sharp hardening of the abdomen occurs against the background of flatulence. At later stages, a hard abdomen may be a consequence of contraction of the uterine muscles due to fetal movements. In this case, this is a normal phenomenon that goes away immediately after relaxation.