Peri-implantation Abstinence and Placental Health

This study examined whether avoiding sexual intercourse during the time when a fertilized egg may attach to the uterus affects placental development and pregnancy outcomes. Couples who were trying to conceive naturally were assigned by chance to one of two groups. Couples in the abstinence group were asked to avoid sexual intercourse for 14 days after ovulation. Couples in the no-restriction group continued their usual sexual activity without a study-imposed restriction. Participants were followed to determine whether pregnancy occurred and, when applicable, through pregnancy and delivery. During pregnancy, ultrasound was used to assess blood flow between the pregnant participant, placenta, and fetus. After delivery, available placentas were examined for tissue changes, blood-vessel development, and markers of oxidative stress, which reflects the balance between potentially damaging oxidants and the body's antioxidant defenses. Pregnancy and birth outcomes were also recorded. The study was designed to improve understanding of whether sexual activity around the time of implantation may be associated with placental development and pregnancy outcomes.