Biopsychosocial stressors and perinatal mental health: The mediating role of social support in a Pakistani cohort.

Perinatal depression and anxiety are major contributors to maternal morbidity, with a disproportionate burden in low- and middle-income countries. In Pakistan, common and modifiable biological risks, including anemia and vitamin D deficiency, may interact with psychosocial factors to influence perinatal mental health. This cohort study enrolled 152 pregnant women from a public hospital in Islamabad; 147 completed baseline assessments (12-32 weeks gestation) and 100 were followed at 6-8 weeks postpartum. Validated Urdu versions of the EPDS, GAD-7, and MSPSS were used alongside hemoglobin and vitamin D assessments at both time points. Longitudinal analyses were conducted using generalized linear mixed models, supplemented by cross-sectional and mediation analyses.Depression was prevalent antenatally (41.5%) and increased postpartum (57.0%), while anxiety declined from 25.2% to 12.0%. Higher hemoglobin was protective against antenatal depression (OR = 0.66) and anxiety (OR = 0.65), but not in longitudinal models. Vitamin D deficiency predicted postnatal depression (OR = 3.15), while sufficiency was associated with remission. Social support showed a strong protective effect (OR = 0.24) and mediated 40% of the hemoglobin-depression association. Baseline symptom severity was the strongest predictor of postpartum outcomes. These findings highlight a substantial burden and point to modifiable nutritional and psychosocial targets for intervention.