Current Preventive Strategies for Preovulatory Progesterone Elevation During Ovarian Stimulation for In Vitro Fertilization

The purpose of this review is to present contemporary measures for preventing the increase in preovulatory progesterone (P) and its adverse effects on ovarian stimulation in in vitro fertilization (IVF). For the last 20 years, the increase of preovulatory P has been a topic of numerous discussions because its role is not fully understood in terms of its impact on pregnancy outcome after IVF. Some studies failed to establish a connection between the preovulatory P increase and successful IVF outcome regardless of the level of P, while, conversely, most other studies have reported on adverse effects of elevated P concentrations. Current strategies to prevent the increase in preovulatory P include an individualized approach with the use of mild stimulation protocols and early application of human chorionic gonadotropin for ovulation induction among good responders, delay in the transfer of fresh embryos from 3rd to 5th day, and cryopreservation of all embryos with the thawed embryo transfer in the natural cycle. Nevertheless, further studies are needed to confirm the current preventive methods or enable the application of new strategies in order to lower or eliminate the detrimental effects of preovulatory P rise during ovarian stimulation in IVF.