Advances in ovulation trigger strategies.

Ovulation trigger (OT) strategy is a cornerstone in modern patient-tailored in-vitro fertilization treatment, securing the optimal number of mature oocytes retrieved without compromising fertilization, embryo development and euploidy rates. Moreover, the OT strategy is taken into consideration before selecting fresh or frozen embryo transfer (freeze-all) to obtain optimal reproductive outcomes while maintaining a low risk of ovarian hyperstimulation syndrome. Several OT agents have been proposed, however, the most common agents used in modern IVF are human chorionic gonadotropin and gonadotropin-releasing hormone agonist. As no OT agent can be generally recommended for universal use, this review evaluates different OT strategies in different clinical scenarios, discussing both the biological plausibility and the clinical evidence.