"Having sex weekly may delay your menopause: Scientists say not getting enough action 'makes the body choose to stop ovulating'," reports the Mail Online.
Women enter the menopause when they stop releasing eggs, usually in their 40s or 50s. Some of the timing seems to be down to genetics, while lifestyle factors such as smoking are also important.
This study was designed to test the theory that women's bodies may stop releasing eggs when the body senses that a woman is no longer likely to get pregnant – for example because she is no longer having sex.
The researchers also wanted to look into a theory that exposure to male pheromones (for example, from living with men) delays menopause.
Researchers analysed information about 2,936 women in their 40s and 50s who lived in the US. The women answered questions about their health, lifestyle, who else lived in their household, and their sexual activity. They were followed up for 10 years.
The researchers found that women were less likely to have gone through the menopause if they had weekly sex. However, the study only shows a link between how often women had sex and their age at menopause. It cannot prove that having more sex directly causes a later menopause.
The researchers did not find any evidence that exposure to male pheromones was linked to timing of the menopause.
Find out more about the menopause.
The researchers who carried out the study were from University College London.
Most of the media headlines suggested that regular sex could delay the menopause, or reduce risk of an early menopause. But the study only shows a link between sexual activity and timing of menopause, not that sexual activity can actually delay menopause.
The news stories themselves gave a more accurate picture of the research, although none pointed out that early menopausal symptoms can affect how likely a woman is to want to have sex.
This was a cohort study. Cohort studies are good ways to look for links between behavioural factors (such as sexual activity) and outcomes (such as menopause). However, they cannot tell us that one directly causes the other. The relationship may be more complex.
Researchers recruited women aged 42 to 52 in 1996 to 1997.
The 2,936 women were all pre-menopausal, although half were experiencing early signs of approaching menopause, such as hot flushes or irregular periods.
The women were asked a range of questions at the start of the study and at 10 follow-up visits over the following 10 years.
Researchers also checked whether the women had been through the menopause at any point during the study. They used the information to calculate:
The first question was to investigate whether menopause might be delayed by the presence of male pheromones in a woman's living space, while the second looked more directly at whether sexual activity was linked to menopause.
The researchers adjusted the results to take account of a range of factors, including:
Most of the women in the study (78%) were married or in a relationship at the start of the study, and 68% lived with their partner. 64% of the women reported weekly sexual activity.
During the study, just under half (45%) of women went through the menopause, with the average age at menopause being 52.
The researchers found no link between women living with men and the likelihood of having gone through the menopause at any point.
However, women who said they had regular sexual activity were less likely to have gone through the menopause than women who said they had sexual activity less than once a month:
The researchers explained their results in an evolutionary framework.
"During ovulation, the woman's immune function is impaired, making the body more susceptible to disease. Hence, if a pregnancy is unlikely owing 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," they said.
On the other hand, if a woman is engaging in regular sex which could lead to pregnancy, "then it may be better to maintain the function of her menstrual cycle for slightly longer".
They point out that menopause is "an inevitability" that cannot be prevented by any behaviour.
Menopause, when women stop releasing eggs and are no longer able to get pregnant, happens to all women eventually. For most women, it happens during their 40s or 50s, but there is a lot of variation.
This study was an attempt to explain part of the reason for the variation in timing of menopause, looking at the question from an evolutionary perspective.
The study has limitations that mean we cannot read too much into it. As with all observational studies, it cannot tell us whether sexual activity is directly linked to age of menopause.
That's because many factors affect whether someone is having sex, and when the menopause happens. For example, if someone is experiencing anxiety or vaginal dryness – both common symptoms of the menopause – they may be less likely to want to have sex.
The findings of the study are interesting for scientists investigating the biology of the menopause and how it might be affected by lifestyle. But they are not particularly relevant to women. We do not know whether changing behaviour to have sex more frequently, for example, could change a woman's time of menopause.
There's no suggestion from this study that women should change their behaviour to delay menopause, even if they wanted such a delay.
Find out more about the menopause.