Recurrent pregnancy loss: systematic review and meta-analysis of overall prevalence and the distribution of major etiological categories

Background: Recurrent pregnancy loss (RPL) is a clinically and emotionally significant reproductive condition, yet its reported prevalence and etiological distribution vary widely across studies. This systematic review and meta-analysis aimed to synthesize available evidence on the prevalence of RPL and the pooled proportions of its major etiological categories. Methods: . Results: = 94.3%), followed by acquired thrombophilia (12, 95% CI, 9-15%), endocrine factors (8, 95% CI, 6-10%), and anatomical factors and hereditary thrombophilia (6, 95% CI, 5-8%). Subgroup and meta-regression analyses suggested that geographic region and selected demographic and temporal study characteristics may contribute to between-study variability in etiological distributions. Conclusion: Reported prevalence and etiological proportions of RPL vary substantially across studies, and a large proportion of cases remain unexplained. The observed heterogeneity, partly associated with regional, demographic, and temporal factors, highlights the need for standardized definitions, diagnostic workups, and reporting practices to improve comparability across studies. Systematic review registration: PROSPERO Registry Number: CRD42024517675.