Sex is a natural, normal part of pregnancy, only if you’re having a normal pregnancy. Penetration and intercourse’s movement won’t harm the baby, who is protected by your abdomen and the uterus’ muscular walls. Your baby is also cushioned by the amniotic sac’s fluid. The contractions of orgasm aren’t the same as labor contractions. Still, as a general safety precaution, some doctors advise avoiding sex in the final weeks of pregnancy, believing that hormones in semen called prostaglandins can stimulate contractions. One exception may be for women who are overdue and want to induce labor. Some doctors believe that prostaglandins in semen actually induce labor in a full-term or past-due pregnancy, since the gel used to ripen the cervix and induce labor also contains prostaglandins. But other doctors believe this semen/labor connection is only theoretical and that having sex doesn’t trigger labor.