Epidemiology, pathophysiology, and interventions for postpartum depression: Systematic review

Table 1 Risk factors for postpartum depression graded by strength of evidence

Evidence level	Risk factors (≥ 2 high-quality SRs/> 1 000-case cohorts)	Representative evidence & effect size
High	Previous major depression; Antenatal (pregnancy) anxiety; Family history of psychiatric disorders	OR ≈ 7.3 for prior depression[12]; OR = 2.09 for family history[13]
Medium	Caesarean birth, especially emergency CS (EMCS OR ≈ 1.18); 25(OH)-vitamin D deficiency (OR ≈ 1.4-1.8 in RCTs)	OR = 1.18 in pooled meta-analysis[14]; Systematic review of RCTs[15]
Low	Single social-stress event; Low income with adequate social support	No consistent pooled effect; evidence limited to small cross-sectional or non-replicated studies[16]

Correlation coefficients (r) reported in some meta-analyses were converted to odds ratios (OR) for consistency using the formula OR ≈ exp (π·r/√3). CS: Caesarean section; EMCS: Emergency caesarean section; aOR: Adjusted odds ratio; OR: Odds ratio; 25(OH)-vit D: 25-hydroxy-vitamin D; SR: Systematic review; RCT: Randomized controlled trial.