Pregnancy

Pregnancy, time between conception and birth. In the human female this takes about 39 weeks, or 9 months. The first symptom of pregnancy is usually a missed menstrual period (though this in itself is not proof) followed perhaps by “morning sickness,” which can continue for some weeks. Tenderness of the breasts and darkening of the nipples usually occur, and frequent urination is common. As the fetus develops, swelling of the abdomen can first of all be felt and then seen. Inside the womb the fetus develops rapidly, and is well formed by 3 1/2 months. After the 28th week, the child is capable of surviving outside the womb, but infant mortality is higher in premature babies than in those carried to full term.

See also: Reproduction.