EFFECT OF COITAL ACTIVITY ON HASTENING ONSET OF LABOR AND PREVENTION OF POSTDATE PREGNANCY

Introduction: Some physicians believe that sexual intercourse at term will hasten the onset of labor. This study is done to determine whether coital activity hastens the onset of labor and prevents postdate pregnancy. Methods: This prospective and cross-sectional study enrolled 215 pregnant women (>36wks) of low risk group who referred to obstetric clinic of university hospital of Shahid Sadoughi in Yazd in 2007-2008.In each weekly prenatal visit, the participants were asked about coital activity in previous week. The data of the labor were compared in the women with coital activity (study group) and those who had not (control group).Statistical analysis was done by SPSS (11.5 version), t-test and Chi-square test. Results: In 105 women, intercourse was done in the last weeks of pregnancy (mean=2.3±0.6 times) and in 110 participants, there was no sexual activity. Coitus at term was accompanied by hastening of labor; less postdate pregnancy and less need for induction of labor. Spontaneous labor occurred in 66.7 of study group and 48.2 of control group. (P<0.05) Postdate delivery beyond 40 week was 7.6 in the study group and 17.3 in the control group that showed a significant decrease. (P<0.05)The incidence of cesarean section, postpartum fever and healthy neonate showed no significant difference in both groups. Conclusion: Coitus at term can be associated with earlier onset of labor, reduction of postdate pregnancy and reduced requirement for labor induction.