Maternal Perinatal Depression, but not Anxiety, Associates with Infants’ Functional Connectivity at One Month of Age

Maternal anxiety and depression have been associated with alterations in functional connectivity (FC) in infancy, a period in which rapid brain development and functional network organisation have been linked to longer term socioemotional outcomes. Investigating maternal anxiety and depression within the same sample is important, given their potential distinct or overlapping influences on brain development. A longitudinal approach is key for understanding how changes in maternal mental health across the perinatal period may influence infant outcomes. We investigated the effects of subclinical prenatal and postnatal maternal depression and anxiety, measured via questionnaires at 32 weeks of gestation and 1 month postpartum, on infants’ FC at one month of age. Task-free FC data were collected during natural sleep using High-Density Diffuse Optical Tomography (HD-DOT) in the home. No associations were observed between maternal anxiety symptoms and FC and neither postnatal depression nor anxiety alone predicted infant FC outcomes. Lower maternal prenatal depression scores were significantly associated with stronger FC in the infants’ frontal network (n=39). In contrast, greater increases in maternal depressive symptoms from the prenatal to postnatal periods were linked to increased frontal FC, particularly when mothers had higher prenatal depression levels (n=28). Most symptom changes were small in magnitude and did not cross clinical thresholds, suggesting largely subclinical and transient mood shifts. While early prenatal exposure may signal vulnerability in specific neural circuits, the subsequent increase in symptoms could trigger compensatory or accelerated development in the same networks. These findings suggest that maternal depressive symptoms, even within subclinical ranges, may influence early infant neurodevelopment, underscoring the importance of targeted maternal mental health support across the perinatal period. Longitudinal research is needed to determine whether these subtle early fluctuations in maternal symptoms influence longer-term trajectories of infant brain development beyond the perinatal window.