Pregnancy history and cognitive aging among older women: the Rancho Bernardo Study

The aim of the study was to examine the association of pregnancy history with trajectories of cognitive function in older women.

Participants were 1,025 women (mean age = 73.1 ± 9.6 y) enrolled in the Rancho Bernardo Study who attended a clinic visit between 1988 and 1992, when pregnancy history (ever pregnant, number of pregnancies, ages at first and last pregnancy) was recorded and cognitive function was assessed with a battery of four tests repeated up to 7 times through 2016. Linear mixed-effects regression models were used to examine the association between pregnancy history and longitudinal change in cognitive function.

Overall, 77% of women had at least one pregnancy; number of pregnancies ranged from 1 to 14 (mean = 2.9 ± 1.7). Ages at first and last pregnancy ranged from 16 to 44 years (mean = 24.9 ± 4.7) and 16 to 49 years (mean = 30.7 ± 5.5), respectively. Of 16 associations tested (4 pregnancy exposures by 4 cognitive tests), one was statistically significant without correction for multiple comparisons. Women who reported ever being pregnant recalled 0.12 fewer words on the Buschke Selective Reminding Test for every year increase in age than women who had never been pregnant (P = 0.05). No other significant associations of pregnancy history with cognitive decline were observed.

Our results show no clinically meaningful long-term influence of pregnancy history on age-related change in cognitive function. These reassuring findings suggest childbearing decisions and timing will not affect cognitive function in older age.