Melatonin and Female Fertility: A Systematic Review and Meta-Analysis of Clinical Supplementation, In Vitro Experiments, and Observational Evidence

Background/Objectives: Melatonin has been proposed as a potential strategy to improve female fertility, but existing evidence is dispersed across assisted reproduction, reproductive disorders, and in vitro studies. This study aimed to comprehensively evaluate the relationships of melatonin supplementation, in vitro melatonin treatment, and endogenous melatonin levels with female fertility.

Methods

PubMed, Web of Science, and EMBASE were searched from inception through February 2026. Randomized and non-randomized intervention studies, observational studies, and in vitro studies involving human oocytes or embryos were included. Random-effects meta-analyses were performed, and certainty of evidence was assessed using GRADE.