Even though I’ve never been pregnant, I’ve lived in the world long enough to have absorbed random nuggets of wild information, like there are lots of ways to try and bring on labour in women at the end of their pregnancies – eating tinned pineapple or really spicy curries being among the more popular. Most of these theories are passed on as old wives tales, and haven’t really been rigorously tested by science. Then again, when you’re 37 weeks into it and have the comfort and mobility of a beached whale, you’re probably willing to try anything to expedite the process.

One theory, that having sex can safely bring on labour in late stages of pregancy, actually seems to make sense. Lovely sexy times are known to cause the release of hormones, such as oxytocin, that are also necessary for starting up labour and beginning uterine contractions that push the tiny human out into the world. Added to that, the male ejaculate itself is known to weaken the chorioamniotic membranes that surround and protect the developing foetus in the uterus, potentially helping the waters to break. Past studies designed to test the link between frequency of sexual activity and onset of labour lack consistent results, so it’s still unknown whether there is a real effect or not.

Now, researcher’s in Kuala Lumpur have addressed this in a large study of 1137 Malaysian women between 36 – 38 weeks of pregnancy, who were recruited and assigned to one of two counselling groups: the first group were counselled that having sex was a safe and natural way to speed up giving birth and avoid having to be induced, while the second (control) group received no such advice. Although it was obvious that receiving medical advice affected behaviour (more women in the advised group had late pregnancy sex than the non-advised controls), the team found that there was no benefit of increasing the frequency of sexual activity in kickstarting the process of giving birth. Perhaps it’s time to revisit the tinned pineapple, after all?

Omar N, Tan P, Sabir N, Yusop E, & Omar S (2012). Coitus to expedite the onset of labour: a randomised trial. BJOG : an international journal of obstetrics and gynaecology PMID: 23145957