Babies whose mothers took part in a prenatal psychotherapy programme showed a modestly reduced right hippocampal volume on follow-up measurement, a brain characteristic that tracked alongside calmer emotional responses at the six-month mark. The findings, drawn from a cohort of 109 infants enrolled in the CARE Project follow-up, appeared in Nature Communications on Oct. 16.
Of the 109 infants enrolled across both arms of the study, 52 had mothers placed in the brief interpersonal psychotherapy group while the remaining 57 received enhanced usual care. Pregnant individuals showing elevated depressive symptoms were recruited into the CARE Project, where researchers placed them into one of two tracks: a brief interpersonal psychotherapy programme or an enhanced version of standard care.
Eight weekly gatherings of 50 minutes apiece formed the backbone of the psychotherapy programme, with each session drawing its focus toward interpersonal connections and the role of social support. Participants assigned to the comparison group received standard obstetric appointments, a single educational session addressing depression in pregnancy, and referrals toward mental health resources available in their communities.
At roughly the six-week mark, MRI scans captured the volumes of the hippocampus and amygdala in each infant, with behavioural observations then carried out once the babies reached six months of age. A conference abstract from the research team documented that hippocampal volume on the right side measured notably smaller among participants assigned to the psychotherapy arm, with a p-value of 0.002 and an effect size of d = 0.62. Neither the left hippocampus nor the amygdala showed a group difference that reached statistical threshold.
Prenatal depression scores were measurably lower among participants receiving psychotherapy than those in the enhanced usual care group, with the difference reflected in an effect size of d = 0.57. A supplementary analysis found that reduced volume in the right hippocampus corresponded with diminished observed negative emotionality at the six-month mark (r = 0.19; p = 0.045).
A correlation of this kind stops short of proving that the observed difference in brain volume actually drove the behaviour in question. Prior human studies linking depression during pregnancy to children's emotional and behavioural outcomes relied mainly on observational methods, the authors noted.
Tracking infant brain development and behavioural patterns only up to the six-month mark, the follow-up study leaves open the question of whether those early gaps carry forward or bear any relationship to mental health outcomes down the line. Infant brain measurements were incorporated into the follow-up work, yet the near-term findings do not confirm any enduring gain in child development.
