Abstract: Frozen-thawed embryo transfer (FET) has been widely used in ART, with the benefits of the improved cumulative pregnancy rate, the prevention of ovarian hyperstimulation, the decreased rate of multiplets. How to improve the success rate of FET is currently one of the hotspots in reproductive medicine. With the research progress of vitamin D in recent years, it is found that vitamin D participates in the regulation of human reproductive function in addition to calcium and phosphorus metabolism. Vitamin D as a salutary factor participates in follicular development, production of steroid hormones and embryo implantation. The vitamin D deficiency is also associated with a variety of gynecological diseases, such as endometriosis and polycystic ovary syndrome. However, there is few research on the effect of vitamin D on the outcomes of FET. We reviewed the application of vitamin D and its clinical effect in FET and ART.

Key words: Reproductive techniques, assisted, Embryo transfer, Vitamin D, Embryo implantation, Embryoquality, Pregnancy outcome