Identifying risk factors associated with postpartum depression: a retrospective case-control study

BACKGROUND: Postpartum depression (PPD) is a common complication following childbirth, affecting approximately 10-20% of women. Despite its prevalence, PPD remains underdiagnosed and insufficiently addressed in routine perinatal care, particularly in large cohorts from German-speaking countries. The study aimed to provide a comprehensive analysis of biological and psychosocial risk factors across the perinatal period that contribute to the onset of PPD. METHODS: A retrospective case-control study was conducted via an online survey with nearly 1,000 recent mothers from Germany, Austria, and Switzerland who had given birth within the last five years. Participants were classified as Cases or Controls based on whether they had experienced PPD and were asked about a broad range of biological and psychosocial factors. Correlational analyses were used to identify factors associated with PPD. RESULTS: A total of 975 women were included in the final analysis. Based on self-reported PPD and Edinburgh Postnatal Depression Scale scores, participants were classified into the Case (n = 470) and Control group (n = 505). Factors with moderate significance generally or during pregnancy, included a history of depression, perceived support during pregnancy, financial and environmental stress during pregnancy, birth satisfaction and traumatic birth experiences. Factors showing moderate significant results postpartum (within the first six weeks after birth) included sleep disturbances, support by the partner, and medical or financial stress. Strongly significant factors present during pregnancy comprised prenatal depression, perceived lack of support, loneliness, general stress and happiness, while strong significant risk factors postpartum included medical support, support by family and friends, and general as well as environmental stress. CONCLUSIONS: The findings highlight significant associations between psychosocial factors and PPD, particularly stress, lack of perceived social support, loneliness during pregnancy, and negative or traumatic birth experiences. Importantly, clinically relevant depressive symptoms were already present during pregnancy in a substantial proportion of women, suggesting that depressive symptoms may already occur before childbirth rather than being restricted to the postpartum period. These results highlight the importance of early screening and preventive strategies during pregnancy, particularly within routine antenatal care. Large-scale anonymous online surveys may further contribute to improved detection of unrecognised PPD cases and help address underdiagnosis of the disorder.