During pregnancy, women\’s reproductive organs undergo special physiological changes. The vaginal walls and cervix were markedly congested. Vaginal epithelial cells are affected by placental estrogen and progesterone. Causes reproductive tract infection and damage. Mechanical stimulation of the vagina and cervix during sexual intercourse can cause the release of endogenous prostaglandins in the uterus through nerve reflexes and body fluid regulation; prostaglandins can cause uterine contractions, thereby causing miscarriage and premature delivery. As the pregnancy months increase, the uterus gradually expands and presses the uterus during sexual intercourse, which can cause premature rupture of membranes and premature delivery.