Progesterone-primed versus conventional antagonist stimulation during the luteal phase in poor ovarian responders undergoing Duo-Stim protocol- a pilot study

Controlled ovarian stimulation (COS) is a crucial step in the success of an in vitro fertilization-embryo transfer (IVF-ET) cycle. Theoretically, the possibility of increasing the number of the oocytes retrieved per attempt could result in a higher chance of obtaining a reproductively competent embryo, thus improving the cumulative live birth rate. Despite the recent advances in techniques of COS, the estimated prevalence of poor responders, according to the POSEIDON criteria, is around 40%. Several strategies have been proposed, aiming to maximise ovarian response and success in these patients; however, no standard management has been outlined yet. One such strategy is double stimulation or DuoStim, which proposes ongoing stimulation in the luteal phase immediately following egg retrieval after stimulation in the follicular phase of the same menstrual cycle. This is based on the evidence that multiple follicular waves can arise in a single ovarian cycle in humans. There is a definite need to block the LH surges during the luteal phase of stimulation as well which can be materialized using the standard GnRH antagonist or, lately, using Progestins, which also sustain LH suppression. While the use of progestins has been accepted in the follicular phase, with the advantages being oral use, reduced costs, and better acceptability, its use during the luteal phase has not yet been explored. Therefore, the hypothesis that progestin-induced LH suppression shall act similarly to antagonist even in the luteal phase has prompted us to compare oral progestins with the accepted antagonist-based LH suppression in the luteal phase of a DuoStim protocol.