Natural versus artificial cycle for endometrial preparation in ovulatory women undergoing frozen-thawed embryo transfer: a randomised controlled trial

This study aimed to determine whether a natural cycle (NC-FET) leads to higher clinical pregnancy rates with fetal heartbeat compared to an artificial cycle (AC-FET) in ovulatory women undergoing frozen-thawed embryo transfer. The results indicated no significant difference in clinical pregnancy rates between the two methods, although NC-FET was associated with fewer cycle cancellations and required more monitoring visits. The findings suggest that NC-FET may be preferable for women with normal ovulatory cycles, especially considering potential higher obstetric risks associated with AC-FET.