A study says the number of children a woman has might affect her ageing. The research found that women who had five children or more, or no children, aged faster. A researcher said: "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...which could reduce lifespan." Surprisingly, women who never gave birth didn't live longer.

Researchers analysed blood, DNA, and health data on 14,000 women. Researchers then modelled the effects of reproduction on rates of longevity. They found that fewer pregnancies could have positive effects on a mother's health. One benefit is a possible lower risk of cancer. However, the "wear and tear" from multiple childbirths could reverse this lowered risk. Another factor that could increase longevity is the social support a mother receives.