The relationship between childhood trauma, socioeconomic status, and maternal depression among pregnant women in a South African birth cohort study

Background: Maternal depression is an important cause of morbidity and mortality. Experiences of childhood trauma contribute to maternal depression, potentially causing adult socio-economic disparities in mental health. We investigate whether adult socioeconomic status (SES) mediates the relationship between childhood trauma and antenatal depression. Methods: We analyzed data from two sociodemographically distinct peri-urban sites in the Western Cape, South Africa in a birth cohort study, the Drakenstein Child Health Study: Mbekweni (N = 510) and TC Newman (N = 413). Data were collected from pregnant women between 28 and 32 weeks’ gestation. Results: Associations between trauma and depressive symptoms differed by site (χ²=2163.6, df = 1419, p < 0.01); direct effects of trauma on depression were 0.24 mean increased symptoms in Mbekweni (p < 0.01) and 0.47 in TC Newman (p < 0.01). Trauma was differentially associated with SES (Mbekweni: −0.10, p = 0.07; TC Newman: −0.05, p = 0.37) and SES with depression (Mbekweni: −0.18, p < 0.01; TC Newman: −0.02, p = 0.62) across both sites. Indirect effects of trauma on depression through SES were 0.018 (95% C.I. −0.002-0.039) in Mbekweni and 0.001 (95% C.I. −0.004-0.006) in TC Newman, suggesting mediation was not supported. SES was a stronger indicator of depression risk in relatively poorer Mbekweni. Conclusion: Neighborhood-level effects and poverty are potentially important modifiers, and points of intervention, for maternal mental health outcomes.