Most pregnant women stop having sex a few weeks before giving birth, as there is a widespread idea that having sex late in pregnancy could trigger labor. But this was found to be just a myth by a team led by Dr Peng Chiong Tan of the University of Malaya in Kuala Lumpur, Malaysia.
"This study is not the final word on the subject. Further research in this area is needed - particularly in a less 'pressure cooker' situation than where labor induction was already scheduled for shortly ahead. It is possible that regular sex a little earlier on, say from 36-37 weeks onward, might have a different effect.", wrote Tan for Reuters Health. "There are good biological explanations for the widespread belief that having sex can bring on labor," wrote the authors.
Amongst the semen's ingredients there's the hormone prostaglandin, which is released in huge amounts by the woman's body as it triggers labor. Also, orgasm can induce uterine contractions. Still, there is no scientific proof that sexual intercourse close to the end of pregnancy starts the labor.
The team assigned 210 pregnant women randomly into two groups: one in which they were advised to have sex as much as possible 4.7 days before their scheduled induction, while in the control group women were advised not to have sex.
60 % of the 108 women advised to have sex did so, while from the other group just 40 %. 56 % of the women who had sex experienced labor on their own, compared to 52 % of the subjects who didn't have sex, thus practically the same numbers. "We speculate that women very close to spontaneous labor felt changes coming on that might reduce their libido, like pains and vaginal discharge," Tan told Reuters Health.
"If correct, this would mean that those women who had sex were the least likely to go into spontaneous labor soon, so they would do less well in terms of spontaneous labor as an outcome in the next few days. We did not have direct data to answer this question satisfactorily, however."
"Based on the findings of our study, women scheduled for induction of labor at term should not be given advice to have sex for the purpose of promoting labor onset", the authors also mentioned.