A recent study led by Molly Fox, an anthropology professor at UCLA, suggests that pregnancy and breastfeeding may have long-term benefits for cognitive function in postmenopausal women. The research, published in Alzheimer's & Dementia, examined data from more than 7,000 women aged around 70 who participated in the Women's Health Initiative Memory Study and the Women's Health Initiative Study of Cognitive Aging. These participants were followed annually for up to 13 years.
The study found a correlation between increased cumulative time spent pregnant or breastfeeding and higher scores on measures of cognition, verbal memory, and visual memory later in life. According to the findings, each additional month of pregnancy was linked to a slight increase in overall cognitive ability scores. Similarly, each additional month of breastfeeding was associated with small increases in both global cognition and specific memory domains.
Molly Fox stated, "Any ways in which we can focus public health outreach or clinical interventions toward higher-risk populations leads to more effective and efficient efforts."
Researchers observed that women who had been pregnant for an average of 30.5 months scored 0.31% higher on global cognition compared to those who had never been pregnant. Women who breastfed for an average of 11.6 months had a 0.12% higher score under similar conditions. Overall, women with any history of pregnancy scored 0.60 points higher on cognitive ability than those without such a history; similarly, women who breastfed scored modestly higher than those who did not.
The effect sizes noted are small but comparable to other protective factors against Alzheimer's disease such as not smoking or maintaining high physical activity levels. Although many women report temporary declines in memory after childbirth—sometimes called "mommy brain"—the study suggests there could be long-term cognitive advantages related to reproductive history.
The researchers acknowledged that further work is needed to understand the biological or social mechanisms behind these associations. They wrote that supportive relationships with adult children might play a role by reducing stress or encouraging healthy behaviors: "more adult children could be a factor in the increased cognitive health, as supportive relationships could possibly buffer stress, promote well-being or encourage healthy behavior."
Fox added: "If we can figure out, as a next step, why those reproductive patterns lead to better cognitive outcomes in old age, then we can work toward figuring out how to craft therapies - for example, new drugs, repurposed drugs or social programs - that mimic the naturally-occurring effect we observed."
This research was funded by the National Heart, Lung and Blood Institute through the National Institutes of Health (NIH), with additional support from the National Institute on Aging at NIH.
The findings highlight potential avenues for future preventive strategies aimed at reducing Alzheimer’s risk among women and call attention to how changing fertility trends might impact brain aging over time.
