Women who spent more cumulative time pregnant and more time breastfeeding scored higher on tests of cognition, verbal memory and visual memory decades later, according to a study led by UCLA anthropology professor Molly Fox and published this month in Alzheimer's & Dementia.
The analysis drew on two large existing datasets, the Women's Health Initiative Memory Study and the Women's Health Initiative Study of Cognitive Aging, which tracked more than 7,000 women who were roughly 70 years old at enrollment and assessed them annually for as long as 13 years. That long follow-up is unusual in research on reproductive history and brain aging, and it allowed the team to look at cognitive performance well past the reproductive years rather than in the immediate aftermath of childbearing.
The framing matters because the brain changes that accompany pregnancy have generally been studied as short-term adaptations, or discussed in terms of the temporary fog many new mothers report. Fox's group approached them instead as part of an evolutionary story about how female brains adjust to reproduction, and asked whether those adjustments leave a lasting mark. The pattern they found points toward a lasting benefit rather than a cost.
This is an observational finding, so it shows an association between reproductive history and later cognitive performance rather than proving that pregnancy or breastfeeding causes better memory. Still, it adds a piece to a picture that has been notably thin: women carry the larger share of dementia risk, and their reproductive biology has rarely been treated as a serious variable in explaining why.