Neuroanatomical Changes in Pregnancy Linked to Depression, Adverse Birth Experience

Bilateral hippocampal volume is positively correlated with a challenging birth experience, and right amygdala volume is positively correlated with perinatal depression symptoms, according to a study published in Science Advances.

In a longitudinal neuroimaging study, researchers assessed neuroanatomical changes associated with pregnancy. They used structural magnetic resonance imaging (MRI) to examine hippocampal and amygdalar volume during the peripartum period. Two scans were conducted at a mean (SD) of 36.26 (0.94) gestational weeks and 21.33 (7.74) days postpartum. Questionnaires were used to assess prenatal and postnatal depression, as well as birth experience.

A total of 88 first-time gestational mothers and 30 nulliparous control women were included in the study, of whom the mean (SD) ages were 32.99 (3.88) and 33.53 (4.61), respectively (P =.51). The mothers and control cohort also had similar education levels (P =.56) and intersession periods (mean [SD], 47.33 [10.90] vs 44.37 [10.22] days, respectively; P =.19). Among mothers, 90.9% conceived naturally, 80.7% had vaginal deliveries, all had singleton births, and 50% of babies were boys.

Women in late pregnancy had significantly smaller right whole amygdala volumes compared with controls (mean, 1886.3 vs 1977.9 mm³, respectively; P =.015) and tended to have smaller left whole hippocampal volumes (mean, 3199.6 vs 3297 mm³, respectively; P =.06). No group differences in amygdala or hippocampal volumes were observed in postpartum. However, the change in right whole amygdala from pregnancy to postpartum differed between mothers and controls (P =.0076).

Further, depression scores increased significantly from pregnancy to postpartum among mothers (F_[1,87], 11.12; P =.0013). Overall, 11.36% of mothers had scores indicating moderate depression during late pregnancy, rising to 17.05% postpartum.

Women who had a worse birth experience were more likely to have symptoms of depression (R, 0.23; P =.03). Worse birth experience was also related with the percent change in left whole hippocampal (R, 0.296; P =.005), right whole hippocampal (R, 0.216; P =.043), and right whole amygdala (R, 0.333; P =.002) volumes.

In post hoc analyses, worse birth experience was associated with greater volume increases in the cornu ammonis 1, dentate gyrus, and hippocampal-and-amygdala transition area in the right hippocampus, as well as in the cornu ammonis 4 in the left hippocampus. Higher depression scores were associated with greater increases in the laterobasal nucleus of the right amygdala.

Study limitations include a lack of baseline MRI data.

The study authors concluded, “[T]his research underscores the critical importance of collecting data about perinatal experiences, both to advance our understanding of the maternal brain and to improve women’s health before, during, and after childbirth.”