Unpacking postpartum depression in rural India: an integrated analysis of risk factors at 12 months and child development outcomes at 18 months of age – findings from the SPRING study

BACKGROUND: Postpartum depression (PPD) negatively affects maternal well-being and early child development (ECD). While research often focuses on the early postpartum depression, symptoms can emerge or persist later in the first year, potentially affecting mothers and children differently at this stage. Yet, the 12-month postpartum period remains understudied globally, particularly in low-resourced settings where contextual stressors are pronounced. This study addresses the urgent need to understand later-stage postpartum depression and how it influences child development at 18 months, a critical period for identifying early developmental delays. METHODS: We analysed longitudinal data from a cluster randomised trial of an integrated mother-child intervention in rural India (Haryana). Mother-child dyads enrolled between 18 June 2015 and 1 July 2017 were assessed for PPD at 12 months using Patient Health Questionnaire-9 (PHQ-9) and for child development at 18 months with Bayley Scales of Infant and Toddler Development-III. We examined PPD risk factors using logistic regression and the association between PPD and ECD through multinomial regression models, accounting for covariates and clustering. RESULTS: Among 2007 mothers assessed at 12 months, PPD prevalence was 13.1% (PHQ-9 ≥ 5). Maternal adverse events (OR = 1.53, CI: 1.35-1.73, p < 0.001) and psychosocial stress (OR = 1.10, 95% CI: 1.08-1.12, p < 0.001) increased PPD odds, while psychosocial support (OR = 0.97, 95% CI: 0.96-0.98, p < 0.001) and higher socio-economic status (OR = 0.72, 95% CI: 0.64-0.79, p < 0.001) reduced them. Among 1250 dyads assessed at 18 months, PPD predicted mild-to-moderate (RRR = 1.63, 95% CI: 1.13-2.36, p < 0.01) and severe (RRR = 1.64, 95% CI: 1.03-2.61, p < 0.05) language delays, but not cognitive or motor delays. These associations were not significant after adjustment. CONCLUSIONS: This is among the first Indian studies to longitudinally examine the association between postpartum depression at 12 months and child development at 18 months, addressing a major evidence gap in rural settings. The study identified a distinct risk profile for postpartum depression shaped by socioeconomic and maternal adversity. Postpartum depression showed domain-specific associations with language delays, explained by contextual factors. These findings highlight the need to integrate evidence-based mental health screening and support for at-risk mothers and children into existing maternal and child health services in rural contexts.