Effects of Melatonin in Women with Polycystic Ovary Syndrome Undergoing ART: A Systematic Review

Polycystic ovary syndrome (PCOS), newly named as Polyendocrine Metabolic Ovarian Syndrome (PMOS) is the most common endocrinopathy affecting women of reproductive age, which often leads to infertility due to anovulation and poor oocyte quality. Poor oocyte quality is a major reason for women's infertility in humans and a barrier to efficient assisted reproduction technology (ART) treatment. Supplementation of melatonin, a free radical scavenger, has been reported to show satisfactory results in women undergoing ART. This review investigates whether the endogenous melatonin or supplementation of melatonin impact on oocyte/embryo quality and pregnancy rate in PCOS patients undergoing ART treatment. Articles published between 2010 and 2025 were reviewed to perform a comprehensive search on observational studies and clinical trials that evaluated the use of melatonin in PCOS patients undergoing in vitro fertilization (IVF) or intrauterine insemination (IUI) or intracytoplasmic sperm injection (ICSI). The databases searched included PubMed, Google Scholar, Science Direct, and Cochrane Library. This systematic review indicates that the group that received melatonin had significantly higher clinical pregnancy probabilities than the control group. Similarly, the melatonin administration significantly enhanced the endometrium thickness (p < 0.001) and the chemical pregnancy rate (30% versus 18%, p = 0.012). Additionally, in comparison to the control group that received metformin alone, the group that received melatonin (3 mg) significantly increased the proportion of top-quality embryos (40.3% vs. 29.9%; p < 0.001). According to this systematic review, melatonin significantly improves endometrial thickness, mature oocytes, high-quality embryos, and pregnancy rates, all of which improve ART outcomes in PCOS patients. Because of its safety, affordability, and efficacy, it is a useful supplement to ART procedures. The most popular and well-tolerated dosage is still 3 mg per day, despite variations in research.