Coitus to expedite the onset of labour: a randomised trial NS Omar, PC Tan, N Sabir, ES Yusop, SZ Omar Department of Obstetrics and Gynaecology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia Correspondence: Dr PC Tan, Department of Obstetrics and Gynaecology, Faculty of Medicine,University of Malaya, Lembah Pantai, 50603 Kuala Lumpur, Malaysia. Email pctan@um.edu.my or tanpenchiong@yahoo.com Accepted 27 September 2012. Published Online 12 November 2012. Objective To evaluate the effect of suggesting coitus as a safe and effective means to expedite labour on pregnancy duration and requirement for labour induction. Design A randomised trial. Setting Antenatal clinic in a university hospital in Malaysia. Population Women from 35 weeks of gestation with an uncomplicated singleton pregnancy. Methods The advise-coitus arm was counselled that coitus at term is a safe, natural and effective means to initiate labour and to avoid labour induction. The control arm was told coitus was safe. Both arms were asked to record coital activity. Main outcome measures Pregnancy duration and labour induction. Results The intervention to delivery interval (mean ± SD) was 3.2 ± 1.4 versus 3.3 ± 1.3 weeks (P = 0.417), with a gestational age at delivery of 39.4 ± 1.2 versus 39.5 ± 1.2 weeks (P = 0.112), and with labour induction rates of 126/574 (22.0%) versus 120/576 (20.8%) (P = 0.666) for the advise-coitus and control arms, respectively, with no statistical difference between the groups. Coitus prior to delivery was more often reported in the advise-coitus arm compared with the control arm: 481/574 (85.3%) versus 458/576 (79.9%) (RR 1.5, 95% CI 1.1–2.0, P = 0.019). Also, the median (interquartile range) reported number of coital acts of 3 (2–5) versus 2 (1–4) (P = 0.006) was higher for the advise-coitus arm. Other pregnancy and neonatal outcomes did not differ between the groups. Conclusions Labour onset and labour induction did not differ in the advise-coitus arm. Keywords Coitus, induction of labour, onset of labour, randomised trial, sexual intercourse. Please cite this paper as: Omar N, Tan P, Sabir N, Yusop E, Omar S. Coitus to expedite the onset of labour: a randomised trial. BJOG 2013;120:338–345. Introduction Sexual intercourse is commonly believed to hasten labour. 1 Semen contains prostaglandin E, 2 breast stimulation has been shown to hasten the onset of labour, 3 and coitus and orgasm stimulates uterine activity, 4 thereby underpinning the expectation that sexual activity at term may expedite labour. In a prospective diary-based study from our centre, coitus at term in healthy women is associated with a shortened gestation and fewer labour inductions, and there is a direct correlation between the frequency of coitus and expedited onset of labour, 5 which provided the impetus for this trial. A Cochrane review on sexual intercourse for cervical ripening and induction of labour identifies only a small trial with 28 women, from which no meaningful conclusions can be drawn. 6 A recent systematic review on the methods of labour induction published in 2011 cites only the same Cochrane review, demonstrating the sparse literature currently available concerning the relationship between sexual intercourse and induction of labour. 7 The UK’s National Institute of Clinical Excellence (NICE) antenatal care guideline states that ‘pregnant woman should be informed that sexual intercourse in pregnancy is not known to be associated with any adverse outcomes’, 8 reflecting the accumulated literature on the safety of coitus in pregnancy. However, 20–80% of pregnant women may have safety concerns about sexual intercourse during pregnancy. 5 We postulate that couples can be reassured about the safety of coitus in late pregnancy and persuaded to engage in coitus as a natural method to initiate labour, so as to avoid labour induction or to hasten an anticipated birth. We 338 ª 2012 The Authors BJOG An International Journal of Obstetrics and Gynaecology ª 2012 RCOG DOI: 10.1111/1471-0528.12054 www.bjog.org General obstetrics