Jan. 14 (UPI) -- Having sex weekly or monthly may help women postpone menopause, a new study has found.
Published Thursday in Royal Society Open Science, the research suggests that women who report engaging in sexual activity weekly -- including sexual intercourse, oral sex, sexual touching and caressing or self-stimulation -- were 28 percent less likely to have experienced menopause at any given age than women who engage in sexual activity less than monthly.
"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," study co-author Megan Arnot, a doctoral candidate in the anthropology department at University College London, said in a press release. "There may be a biological energetic trade-off between investing energy into ovulation and investing elsewhere, such as keeping active by looking after grandchildren."
The findings of Arnot and her colleagues are based on an analysis of the U.S.-based Study of Women's Health Across the Nation, or SWAN, the largest cohort study available to research aspects of the menopause transition. The collected data from 2,936 women who were recruited for the SWAN study in 1996-97.
The interviews were carried out over a 10-year period, during which 1,324, or 45 percent, of the women experienced a natural menopause, at an average age of 52. On average, participants had two children. In addition, 78 percent were married or in a relationship and 68 percent were living with their partner.
According to the North American Menopause Society, during the menopause transition, women experience the physical effects of falling estrogen levels, like hot flashes, night sweats and vaginal dryness. These effects can undermine sexual motivation and drive, the society adds.
Though not directly related to menopause, age-related decreases in testosterone may also reduce desire in midlife women, as the hormone plays a role in sex drive and sexual sensation.
A study published recently in the journal Menopause found that menopausal women typically experience increases in sexual dysfunction, likely due at least in part to these physical symptoms.
For the current study, participants 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.
The most frequent pattern of sexual activity was weekly, at 64 percent. After modelling the relationship between sexual frequency and the age of natural menopause -- and controlling for estrogen level, education, body mass index, race, smoking habits, age at first occurrence of menstruation, age at first interview and overall health -- they found that women of any age who had sex weekly were 28 percent less likely to experience menopause compared to those who had sex less than monthly.
Similarly, those who had sex monthly were 19 percent less likely to experience menopause at any given age compared to those who had sex less than monthly.
The authors also tested whether living with a male partner -- and being exposed to male pheromones -- delayed menopause. They found no correlation, regardless of whether the male was present in the household or not.
"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," Arnot noted.
"Menopause is, of course, an inevitability for women, and there is no behavioral intervention that will prevent reproductive cessation," co-author Ruth Mace, a professor of anthropology at University College London, added. "Nonetheless, these results are an initial indication that menopause timing may be adaptive in response to the likelihood of becoming pregnant."