The Protective Effect of Breastfeeding and Ingesting Human Breast Milk on Subsequent Risk of Endometriosis in Mother and Child: A Systematic Review and Meta-Analysis.

Background: Endometriosis is a chronic and debilitating disease characterized by ectopic, endometrium-like tissue outside the uterine cavity. Objective: The current meta-analysis was conducted to evaluate the effect of breastfeeding and ingesting human breast milk on the subsequent risk of endometriosis. Materials and Methods: The English and Persian databases were systematically searched in accordance with the Mesh browser keywords and free-text words until March 12, 2022. The Newcastle-Ottawa was used to evaluate the quality of the included studies. Publication bias was assessed using Begg's and Egger's tests, and funnel plot. The heterogeneity of studies was evaluated using I 2 statistics. Results of the random-effects meta-analysis were presented using odds ratios (ORs) and 95% confidence intervals (CIs). Results: In total, 18 articles with 10,994 subjects were included in the meta-analysis. Overall, the pool estimates show that breastfeeding (OR = 0.79, 95% CI: 0.71-0.88, I 2  = 89%) and ingesting human breast milk (OR = 0.67, 95% CI: 0.50-0.83, I 2  = 84.5%) have significantly a protective effect on the risk of endometriosis. Conclusion: Our findings confirm an inverse association between endometriosis risk and ingesting human breast milk, and breastfeeding. Therefore, the importance of breastfeeding for both mother and child should be considered by policymakers and health care providers.