Couples should check with their obstetricians regarding sexual practices during pregnancy, so that all of their individual circumstances are addressed.

Placenta previa is the condition in which the placenta implants in the lower part of the uterus, covering the cervix. It occurs in about one in 200 pregnancies at term. It is associated with bleeding that can be quite severe. Delivery must be by Caesarean section so that the fetal blood supply is not disrupted before the infant emerges from the uterus. It is more common in women who have had previous pregnancies, older women, and after a previous C-section.

Prior to 20 weeks of pregnancy, as many as 5 percent of women will show evidence of placenta previa on ultrasound. Almost all will have cleared up when evaluated later in the pregnancy. The placenta does not actually move once it implants, but growth of the uterine wall pulls it away from the cervical opening.

Intercourse and vaginal exams should not be done in the presence of a placenta previa because of the risk of bleeding. Sexual activity may resume if an apparent placenta previa diagnosed early in pregnancy is shown to have cleared up on a later ultrasound.