There is a widespread belief that sex during the later stages of pregnancy can jumpstart labour, but now a new study says that doesn't appear to be so.
The researchers in Malaysia found that there were no differences in the timing of delivery between women who had sex near term and those who didn't.
"We are a little disappointed," said Tan Peng Chiong, an obstetrics and gynaecology professor at the University of Malaya and one of the authors of the study, which was published in BJOG: An International Journal of Obstetrics and Gynaecology.
Tan said that scientists have proposed plausible biological explanations for why it might help. For one, semen contains a hormone-like substance called prostaglandin, which is used in synthetic form to induce labour.
The researchers invited more than 1,100 women to participate, all of whom were 35 to 38 weeks pregnant.
Half were advised by a physician to have sex as a means of safely expediting labour, while the other half were told that the effects on labour were unknown. The researchers then found that about 85pc of the women who were encouraged to have sex did follow the doctor's advice, while 80pc of women in the other group also had sex.
The rates of induced labour were similar in both groups: 22pc of those advised to have sex and 20.8pc of the other group, a difference so small it is likely to have been driven by chance.