Women with two to three children live longest, while having more than four is linked to shorter lives, research on biological ageing suggests.

The study also found timing matters, with pregnancies roughly between ages 24 and 38 linked to more favourable ageing and longevity patterns.

Somewhat unexpectedly, childless women showed faster ageing than women with a few children, though this may be explained by other lifestyle or health factors.

Doctoral researcher Mikaela Hukkanen, who conducted the study, said: “From an evolutionary biology perspective, organisms have limited resources such as time and energy.

“When a large amount of energy is invested in reproduction, it is taken away from bodily maintenance and repair mechanisms, which could reduce lifespan.”

The research, conducted by the University of Helsinki and the Minerva Foundation Institute for Medical Research, followed nearly 15,000 female twins born between 1880 and 1957. Participants completed a questionnaire in 1975 and have been followed regularly since.

A novel aspect was measuring ageing biologically using epigenetic clocks, which detect ageing-related cellular changes by analysing chemical markers in blood samples. These can identify signs of biological ageing years before death.

The epigenetic analysis of more than 1,000 participants supported the mortality findings, showing women with many children or no children were biologically somewhat older than their chronological age.

Dr Miina Ollikainen, who led the study, said: “A person who is biologically older than their calendar age is at a higher risk of death. Our results show that life history choices leave a lasting biological imprint that can be measured long before old age.

“In some of our analyses, having a child at a young age was also associated with biological ageing.

“This too may relate to evolutionary theory, as natural selection may favour earlier reproduction that entails shorter overall generation times, even if it entails health-related costs associated with ageing.”

The researchers emphasised that the findings apply only at population level and do not demonstrate cause-effect relationships.

Dr Ollikainen added: “An individual woman should therefore not consider changing her own plans or wishes regarding children based on these findings.”

An NHS GP and menopause specialist has urged women to do three monthly health checks, examining their chest, vulva and moles.

Dr Carys Sonnenberg, an NHS women’s health GP and founder of the Rowena Health Menopause Clinic, shared the recommendation on TikTok, suggesting the first of each month as a good time to perform the checks.

She said: “It’s the first of the month, so it’s a really good day to do your chest check, to do your vulva check, and also to examine any moles that you have on your body, not forgetting your head.”

“When you are looking at your body, it’s really good to know what’s normal for you.

“So the CoppaFeel! website has got some brilliant information, with teaching you how to examine your chest properly, and knowing what problems you might be looking for, and anything that you need to report to your GP.”

CoppaFeel! is a breast cancer awareness charity that encourages monthly chest examinations.

The charity states: “Be aware of changes to your breasts and chest that might be signs of breast cancer.

“Getting into the habit of checking your chest every month is an easy way to stay on top of this.

“It’s also important to understand that some of these changes happen naturally, like during your monthly cycle.”