As any woman who has ever been overdue and anxious to get to the finish line will tell you – there are lots of ideas out there about how to bring on labour. There is the eating hot curries idea. Then there is the driving over the railway lines without using the break idea. Some woman swear by castor oil or enormous quantities of fresh pineapple, although both have unpleasant side effects! We’ve even heard of women repeatedly jogging up flights of stairs as if to shake their baby loose. But the question most likely to bring on either fits of giggles or extensive eye rolling is… does sex induce labour?
You don’t have to go too far to find someone who will swear up and down that it was having sex that last time that kick-started their labour. After all sex is what started it if your baby was made the old fashioned way. Doesn’t it stand to reason that sex can somehow help at the end?
The reason why researchers have explored this link is threefold. Firstly semen contains prostaglandin which promotes uterine contractions and offers cervix-softening properties. Then there are the uterine contractions of the female orgasm. Finally breast stimulation has been shown to hasten labour. It is these factors combined which would seem to suggest that where a cervix is almost ripe and a uterus almost ready, sex might help things along.
However despite how often the question is asked by pregnant women, minimal research exists on whether sex induces labour. Most studies that have been conducted are relatively small and largely inconclusive. A research study conducted between March 2008 and June 2011 attempted to determine once and for all whether sex induces labour.
Including 1200 participants all around 36 weeks pregnant, this study split the women into two groups - one that was told sex is a natural method to safely induce labour, and the other that was told there is no conclusive evidence that sex induces labour. The researches then collected information about how often the women had sex between recruitment and the onset of labour. They also collected data on how long after recruitment labour occurred and the number of inductions.
So what did the study find? The group of women told that sex induces labour seemed to be having more sex in their final weeks of pregnancy than those in the group told sex had no obvious benefit. However the women who engaged in more sex got to the baby-birthing finish line no faster than their sceptical peers. There was also a similar rate of induction in both groups. There are problems with this study though in that it did not consider how much sex the women were having and compare that to how quickly they went into labour. You have to eat 7 large fresh pineapples before you seen any uterine activity. If sex does induce labour… how much sex does it take?
The long and short of it is, while there might seem to be logical reasons why sex might induce labour, we have no conclusive evidence to prove it is true. So if in those last weeks of pregnancy you feel like having sex, and you have not be told to do otherwise by your doctor or midwife, then feel free to indulge to your heart’s content…. just don’t pin your hopes on the idea that sex induces labour!
Omar, NS, Tan, PC, Sabir, N, Yusop, ES & Omar, SZ 2013, “Coitus to expedite the onset of labour: a randomised trial.” BJOG : an international journal of obstetrics and gynaecology, vol. 120, no. 3, pp. 338–345, viewed 27 October, 2013, <http://www.ncbi.nlm.nih.gov/pubmed/23145957>.