Women who have sex more often are less likely to have an early menopause, according to research that raises the intriguing possibility that lifestyle factors could play a more significant role than previously thought in determining when the menopause occurs.

The study, based on data collected from nearly 3,000 women who were followed for 10 years, found that those who reported engaging in sexual activity weekly were 28% less likely to have experienced menopause at any given age than women who engaged in sexual activity less than monthly.

Megan Arnot, a PhD student at UCL and the study’s first author, said the findings suggest that if a woman is not having sex – and there is no chance of pregnancy – the body might “choose” not to invest in ovulation. “There may be a biological energetic trade-off between investing energy into ovulation and investing elsewhere, such as keeping active by looking after grandchildren,” she said.

The findings are based on data collected from 2,936 women recruited into a US menopause study called the SWAN cohort in the 1990s. The women were aged 45 years on average at the start of the study and were mostly married or in a relationship.

The women were asked to respond to several questions, including whether they had engaged in sex with their partner in the past six months, the frequency of sex, including whether they had engaged in sexual intercourse, oral sex, sexual touching or caressing in the past six months, and whether they had engaged in self-stimulation in the past six months. The most frequent pattern of sexual activity was weekly (64%).

None of the women had yet entered menopause, but 46% were starting to experience early menopause symptoms, such as changes in period cycle and hot flushes. By the 10-year follow-up, 45% of the women had experienced a natural menopause at an average age of 52.

The study, published in the journal Royal Society Open Science, found that women of any age who had sex weekly were 28% less likely to experience the menopause compared with those who had sex less than monthly. Those who had sex monthly were 19% less likely to experience menopause at any given age compared with those who had sex less than monthly.

The researchers have yet to establish what the biological mechanism might be that would result in sexual activity actively influencing when a woman’s reproductive cycle comes to an end.

The menopause is thought to occur when the number of maturing egg follicles in the ovaries drops beneath a critical threshold.

One possibility is that sexual activity stimulates the release of oestrogen, which plays a role in the complex cascade of chemical signals that result in an egg being released each month before the menopause. But the study did not test this directly. A challenge, Arnot said, is that “the whole hormonal mechanisms surrounding the menopause is really poorly understood”, meaning the work does not slot neatly into a well-established framework.

Another possibility is that the two factors – how often a woman has sex and age at menopause – are both determined by some other hormonal or biological factor that was not measured in the study. In this case the link would not be causal.

The study looked at whether living with a male partner played a part but found no link, suggesting that exposure to male pheromones did not explain the findings.

Prof Ruth Mace, an evolutionary anthropologist at UCL and the paper’s senior author, said: “The menopause is, of course, an inevitability for women, and there is no behavioural intervention that will prevent reproductive cessation. Nonetheless, these results are an initial indication that menopause timing may be adaptive in response to the likelihood of becoming pregnant.”