A study suggests the number of children a woman has might affect her rate of ageing. Research from Finland found that women who had five children or more, or no children, aged faster than those who had few kids. A researcher 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." She was surprised about the shorter lifespans of women who never gave birth.

The researchers analysed health data on 14,836 women. Researchers examined DNA data and blood, then modelled the effects of reproduction on women's rates of longevity. A researcher found that having fewer pregnancies could have positive effects on a mother's health. One benefit is a possible lower risk of breast and ovarian 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 for having children.