History of miscarriage and postpartum depression: a systematic review and meta-analysis of observational studies

Objective: To assess the association between postpartum depression (PPD) and miscarriage history and the role of moderators. Methods: We identified observational studies of PPD rates in women with vs. without miscarriage history in Embase and Medline in July 2023 and updated in October 2024. Study quality was evaluated using the Newcastle-Ottawa Scale. The primary outcome was the odds ratio (OR, 95 % confidence intervals [95 %CI]) of PPD in women with vs. without miscarriage history. Meta-regression analyses included the effects of age, marital status, history of depression/anxiety and parity; subgroup analyses were based on PPD assessment methods and timepoint, cohorts from low-/middle-vs. high-income countries and cohorts with single vs. multiple miscarriages. We performed sensitivity analyses excluding poor-quality, cross-sectional studies and sequentially each study. Results: Seventeen and two studies were rated as poor- and fair-quality, respectively. In 19 studies (n = 111,772), women with miscarriage history were at higher PPD risk compared to women without miscarriage (OR = 1.62, 95 % CI = 1.26 to 2.07, p < 0.001), with substantial heterogeneity (I2 = 99.8 %). We detected some asymmetry in the funnel plot. The Egger's test was positive (p = 0.04). The OR using the trim-and-fill method was 0.98 (95 %CI = 0.70 to 1.37, p = 0.91). Higher miscarriage-related PPD ORs were estimated in low-/middle-vs. high-income countries (OR = 2.09, 95 %CI = 1.47 to 2.95, k = 10, n = 5,665, vs. 1.23, 95 %CI = 0.96 to 1.58, k = 9, n = 106,107, p = 0.02). After excluding low-quality studies the PPD OR dropped (1.15, 95 %CI = 0.50 to 2.64, k = 2, n = 2,911, p = 0.75). Conclusions: Women with miscarriage history had higher PPD risk, although small study effects and low study quality may have led to an overestimation.