Number Of Children You Have May Affect Lifespan — Study

 

 

A new study by researchers at the University of Helsinki in Finland suggests that both having more children than average and having no children at all may be linked to a shorter lifespan and faster biological ageing.

However, the researchers caution that the findings should not be interpreted as personal health advice. Instead, they reflect population-level patterns that align with theories in evolutionary biology.

Biologist Mikaela Hukkanen of the University of Helsinki explained that from an evolutionary perspective, living 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,” Hukkanen said.

Previous studies have suggested that having more children can be associated with lower wealth later in life. But most of that research focused on only one or two factors—such as the age at which a woman had her first child or the total number of children she had.

In the new study, researchers took a broader approach by examining the relationship between childbearing history and mortality.

“They analysed data from 14,836 women who were all twins, a design that helped reduce the influence of genetic differences. In addition, a subset of 1,054 participants was assessed for biological ageing markers.

Participants were divided into seven groups based on the number of children they had and the timing of their pregnancies, including a separate group of women who had never had children.

The analysis found that women who had no children and those in the highest group—who had an average of 6.8 children—tended to show higher risks of mortality and faster biological ageing.

Women who had children at a younger age also appeared to age biologically faster and had shorter lifespans.

However, this link largely disappeared after researchers accounted for other factors such as alcohol use and body mass index (BMI).

By contrast, the association between increased ageing risk and both childlessness and having a large number of children remained even after adjusting for these factors.

The lowest levels of biological ageing and mortality risk were observed among women who had an average number of children around two to three and who had their pregnancies between the ages of 24 and 38.

Epigeneticist Miina Ollikainen, also from the University of Helsinki, said life-history decisions can leave measurable biological effects long before old age.

“In some of our analyses, having a child at a young age was also associated with biological ageing,” Ollikainen said. “This may relate to evolutionary theory, where natural selection can favour earlier reproduction—even if it carries health-related costs linked to ageing.”

The researchers emphasised that the results do not prove a direct cause-and-effect relationship.

Instead, they highlight statistical associations observed across a large population.

Many other factors influence lifespan and biological ageing, the researchers noted, and the findings should be interpreted alongside other studies that point to potential health and social benefits of parenthood.

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