It is largely a matter of predisposition – but apparently another factor also influences when women come into menopause: an active sex life is linked to the later onset of menopause, according to a statistical study. The trend may reflect that the female body is guided by the likelihood of conception, the researchers say. According to them, this in turn fits the so-called “grandmother hypothesis” as an explanatory approach for menopause.
The menopause is a mystery: Why do menopause end the fertility of women in the second third of their lives, while men remain fertile throughout their lives? The menopause describes the time of the hormonal change before and after the last menstrual period, which also marks the last ovulation. There are hardly any parallels to this in the animal kingdom: as a rule, the females are capable of reproduction until death. The best-known explanation for the evolutionary origin of menopause is the grandmother hypothesis. It says that after the menopause, women were particularly important for the survival of the clan and thus of their own genes through their experiences: by wisely caring for their children and grandchildren, they were able to secure more offspring than by giving birth to their own children, said Theory.
Study with intimate insights
As Megan Arnot and Ruth Mace from University College London report, there is already statistical evidence that married women tend to go into menopause later than single women. In the context of their study, they have now investigated the question of what could be behind this connection: Is it just the close co-existence with a partner that influences this effect or is it related to sexuality? To get information, they evaluated data from a US study on women’s health.
When the study began in 1996, the average age of the approximately 3,000 participants was 45 years. None of the women had entered menopause. In addition to a lot of information, the data also included insights into the intimate lives of the participants: They indicated how often they were sexually active – be it in the form of sexual intercourse or other practices. The study ran for ten years, during which the women came into the menopause. Taking other factors into account, including estrogen levels, education, weight and general health, the scientists carried out a statistical analysis to find out whether there was a link between sexual behavior and the age at which menopause started.
Results in line with the grandmother hypothesis
As the two researchers report, the average start of menopause was 52 years. When looking at the range of this age, however, it became apparent that women who had sex weekly entered the menopause significantly later than study participants who stated that they were only sexually active about once a month. The statistical trend continued for women who practiced even less sex, the researchers report. The mere presence of a partner in the household, however, did not matter, they found.
According to the researchers, there is a plausible explanation for the connection found: the results suggest that the female body is more likely to begin the “menopause saving program” when a woman has little sex and therefore there is little chance of pregnancy anyway. This in turn fits into the concept of the grandmother hypothesis: if pregnancy is unlikely, it seems more advantageous to save the energy for menstruation and to invest in caring for the already existing offspring. “An assumption made under the grandmother hypothesis is that menopause enables more mature women to improve their fitness levels so that they can look after their clans at an advanced age,” said Arnot.
Her colleague Mace concludes: “At some point, menopause definitely comes – there is no natural behavioral intervention that can prevent the end of female fertility. Nevertheless, these results are a first indication that the timing of the menopause is linked to a certain extent with the likelihood of getting pregnant, ”summarizes the scientist.
Source: University College London, technical article: Royal Society Open Science, doi: 10.1098 / rsos. 191020
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