Relationship between parenthood and cortical thickness in late adulthood

Abstract

Pregnancy and the early postpartum period alter the structure of the brain; particularly in regions related to parental care. However, the enduring effects of this period on human brain structure and cognition in late life is unknown. Here we use magnetic resonance imaging to examine differences in cortical thickness related to parenthood in late life, for both sexes. In 235 healthy older women, we find a positive relationship between parity (number of children parented) and memory performance in mothers. Parity was also associated with differences in cortical thickness in women in the parahippocampus, precuneus, cuneus and pericalcarine sulcus. We also compared non-parents to parents of one child, in a sub-sample of older women (N = 45) and men (N = 35). For females, six regions differed in cortical thickness between parents and non-parents; these regions were consistent with those seen earlier in life in previous studies. For males, five regions differed in cortical thickness between parents and non-parents. We are first to reveal parenthood-related brain differences in late-life; our results are consistent with previously identified areas that are altered during pregnancy and the postpartum period. This study provides preliminary evidence to suggest that neural changes associated with early stages of parenthood persist into older age, and for women, may be related to marginally better cognitive outcomes.

Trial registration: ClinicalTrials.gov NCT01038583.

Fig 1

(a) Spearman’s Rho for brain regions showing a significant relationship between cortical thickness and number of children for female. Regions highlighted in red (right parahippocampal gyrus) depict a positive relationship, regions highlighted in blue (left pericalcarine sulcus and cuneus) depict a negative relationship. (b) Cohen’s d for the difference between females with one child and females with zero children. Regions highlighted in blue (left caudal middle frontal/DLPFC, right pericalcarine sulcus) depict a negative Cohen’s d and thinner GM in mothers, compared with non-mothers. (c) Cohen’s d for the difference between males with one child, to males with zero children. Regions highlighted in red (right temporal pole) depict a positive Cohen’s d and thicker GM in fathers, regions highlighted in blue (left caudal anterior cingulate cortex) depict a negative Cohen’s d and thinner GM in fathers compared with nonfathers.

Fig 2. Relationship between Hopkins Verbal Learning Task (HVLT) recall score and the number of children a woman has mothered.

HVLT score was first controlled for age and education, then converted to rank, such that each participant’s memory score (N = 260) was converted into rank order (1 to 260).