Renewing ovarian stimulation.

Conventional ovarian stimulation protocols were designed for fresh embryo transfer. They start in the early follicular phase, i.e. the infamous day 2-3, gonadotrophin-releasing hormone analogues are used to prevent premature ovulation, and the stimulation is harnessed due to the fear of ovarian hyperstimulation syndrome and the decreasing chance of a live birth following a fresh transfer. The advent of vitrification allows a confident cancellation of fresh transfers and effective oocyte/embryo freezing for future use. Today, many stimulation cycles are not intended to involve a fresh embryo transfer. Ovarian stimulation for freeze-all cycles can be vastly different from conventional stimulation. The quantitative and qualitative oocyte yield seems independent of the starting day, and the early or late follicular or luteal phase may have distinct advantages for different needs. A variety of pituitary suppression protocols including oral progestins or not using exogenous suppression at all can be employed without compromising oocyte quantity and quality. Stimulation can cautiously aim for the patient's maximal potential since the agonist trigger without a fresh transfer curbs the risk of ovarian hyperstimulation syndrome. Patients can be even stimulated multiple times in a menstrual cycle when deemed beneficial. Ovarian stimulation is more patient and physician friendly than ever.