Pregnancy and breastfeeding may offer long-term cognitive benefits for women, according to a new study published this month in Alzheimer’s & Dementia. Researchers at UCLA have found a correlation between cumulative time spent pregnant and breastfeeding and stronger cognitive function in postmenopausal women.
The study, led by UCLA anthropology professor Molly Fox, analyzed data from over 7,000 women around age 70, followed for up to 13 years through the Women’s Health Initiative Memory Study and the Women’s Health Initiative Study of Cognitive Aging. The findings suggest that women with longer reproductive histories demonstrated greater cognition, verbal memory, and visual memory later in life.
“Any ways in which we can focus public health outreach or clinical interventions toward higher-risk populations leads to more effective and efficient efforts,” said Professor Fox. This research is particularly relevant given that women are disproportionately affected by Alzheimer’s disease, a disparity that remains incompletely understood.
The researchers hypothesized that longer breastfeeding durations, more pregnancies, and a higher ratio of the two would correlate with improved cognitive function. The data supported this theory. Women who were pregnant for an average of 30.5 months showed a 0.31% higher global cognition score compared to those who had never been pregnant. Similarly, women who breastfed for an average of 11.6 months exhibited a 0.12% higher global cognition score, assuming all other factors were equal.
While the effect sizes are small – each additional month of pregnancy was associated with a 0.01-point higher overall cognitive ability score, and each additional month of breastfeeding with a 0.01-point increase in overall cognitive ability, as well as a 0.02-point increase in verbal and visual memory – researchers emphasize their significance. These effect sizes are comparable to those observed with other established protective factors for cognitive health, such as avoiding smoking and maintaining high physical activity levels. Given the challenges in preventing and treating Alzheimer’s disease, even small reductions in risk are considered valuable.
The study acknowledges the well-documented short-term cognitive changes many women experience after childbirth, often referred to as “mommy brain,” characterized by temporary memory lapses and cognitive difficulties. However, the findings suggest that these postpartum effects may be offset by long-term cognitive benefits associated with pregnancy and breastfeeding.
Specifically, women who had been pregnant demonstrated 0.60-point higher cognitive ability scores compared to those who had never been pregnant. Breastfeeding was also linked to improved cognitive performance, with women who had breastfed scoring 0.19 points higher overall and 0.27 points higher on verbal memory tests compared to those who had never breastfed.
The precise mechanisms underlying this relationship remain unclear. Researchers speculate that having more children could contribute to increased cognitive health through supportive relationships that buffer stress and promote well-being. Further investigation is needed to fully elucidate the biological and sociocultural processes at play.
The research team is now focused on identifying the specific mechanisms that link reproductive histories to cognitive resilience. They hope to uncover potential therapeutic targets that could “replicate or enhance the protective effects observed in women with specific reproductive histories,” according to the study.
“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,” Professor Fox explained.
The findings have implications for preventative strategies aimed at reducing the risk of Alzheimer’s disease in women. Understanding these patterns could also inform research into how changing fertility behaviors may impact trends in brain aging at the population level.
This research builds upon a growing body of evidence suggesting a complex relationship between pregnancy, breastfeeding, and women’s brain health across their lifespans. The study utilized data collected from the Women’s Health Initiative Memory Study and the Women’s Health Initiative Study of Cognitive Aging, which involved reproductive history interviews, annual global cognitive assessments, and multi-domain cognitive testing of postmenopausal women.
The Women’s Health Initiative funded this research, with support from the National Heart, Lung, and Blood Institute under the National Institutes of Health. Professor Fox’s work was also supported by the National Institute on Aging at the National Institutes of Health.
