The Association of Sexual Intercourse During Pregnancy With Labor Onset

membrane. Subjects were investigated in two groups regarding history of coitus in the last week of pregnancy. A questionnaire containing demographic questions, obstetrical history, and sexual activity was completed by trained midwife through face-to-face interview. Chisquare test, Fisher's exact test, and t-test were used to check the homogeneity of the two groups for basic and confounding variables. Independent-samples t-test was used to compare differences between groups in terms of mean gestational age. Results: There was no significant difference between groups in age (P = 0.434), body mass index (P = 0.705), neonatal weight (P = 0.421), maternal education (P = 0.963), occupation (P = 0.381), and parity (P = 0.925). Gestational age at the time of delivery was significantly lower in intercourse group in comparison with control group based on last menstrual period (P = 0.012) and ultrasonography (P = 0.002). There was no correlation between intercourse and cause of admission (P = 0.720). Type of delivery (cesarean section or vaginal delivery) was not affected by intercourse (P = 0.820) or contact with semen (P = 0.841). Results showed no significant difference in neonatal weight based on presence of sexual intercourse (P = 0.422) or contact with semen (P = 0.583) at the last week of pregnancy. Conclusions: Sexual activity in last week of pregnancy might be associated with the onset of labor. Therefore, in the absence of complications in term pregnancy, sexual activity can be considered as a natural way to prevent post term pregnancy.