Having more sex could lower the risk of early menopause, new research has suggested.
The study, published in Royal Society Open Science, found that women who engage in sexual activity weekly or monthly have a lower risk of entering the menopause early, in comparison to those who have some form of sex less than monthly.
Researchers from UCL observed that women, 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.
Sexual activity includes sexual intercourse, oral sex, sexual touching and caressing or self-stimulation.
The research is based on data from the USA's Study of Women's Health Across the Nation (SWAN) and is the largest and most representative study analysing aspects of the menopause transition.
The research is based on data collected from 2,936 women, with the mean age at the first interview being 45.
On average participants had two children, were mostly married or in a relationship (78%), and were living with their partner (68%).
Interviews were carried out over a ten-year period, during which 1,324 (45%) of the 2,936 women experienced a natural menopause at an average age of 52.
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 engaged in sexual intercourse, oral sex, sexual touching or caressing in the last six months and whether they had engaged in self-stimulation in the past six months.
Interestingly, the most frequent pattern of sexual activity was weekly (64%).
None of the women had entered menopause at the start of the study, but 46% were in early peri-menopause (starting to experience menopause symptoms, such as changes in period cycle and hot flashes) and 54% were pre-menopausal (having regular cycles and showing no symptoms of peri-menopause or menopause).
Researchers found that by modelling the relationship between sexual frequency and the age of natural menopause, women of any age who had sex weekly had a hazard ratio of 0.81, whereas women of any age who had sex monthly had a hazard ratio of 0.72.
This corresponded to a likelihood whereby women of any age who had sex weekly were 28% less likely to experience the menopause compared to those who had sex less than monthly.
Likewise, those who had sex monthly were 19% less likely to experience menopause at any given age compared to those who had sex less than monthly.
Study authors had some theories about the explanations behind the results.
“The findings of our study suggest that if a woman is not having sex, and there is no chance of pregnancy, then the body 'chooses' not to invest in ovulation, as it would be pointless,” first author on the study, Megan Arnot from UCL explained.
Arnot suggests there maybe something of “a biological energetic trade-off” between investing energy into ovulation and investing elsewhere, such as keeping active by looking after grandchildren.
“The idea that women cease fertility in order to invest more time in their family is known as the Grandmother Hypothesis, which predicts that the menopause originally evolved in humans to reduce reproductive conflict between different generations of females, and allow women to increase their inclusive fitness through investing in their grandchildren.”
During ovulation, the woman's immune function is impaired, making the body more susceptible to disease. Given a pregnancy is unlikely due to a lack of sexual activity, then it would not be beneficial to allocate energy to a costly process, especially if there is the option to invest resources into existing kin.
Last author, Professor Ruth Mace (UCL Anthropology), added: “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.”