Luteal Phase Support With GnRH Agonist After GnRH Agonist Triggering in IVF/ICSI Cycles

It is currently established that obtaining a large number of oocytes is a key of success in IVF/ICSI cycles. However, it is also a risk factor for ovarian hyperstimulation syndrome (OHSS) and a risk factor of implantation failure after fresh embryo transfer because of the alteration of endometrial receptivity. A freeze all strategy can be proposed to avoid these risks but vitrification of embryos, although more efficient than slow freezing in terms of embryo survival, is not without risk. Furthermore, proper endometrial and embryo timing for frozen-thawed embryo transfer is still debated. Recent preliminary works suggest another possible way to combine an optimal ovarian response with the recovery of a large number of oocytes, good chances of implantation and a reduced risk of OHSS. To achieve this goal, ovulation triggering and luteal phase support need to be modified together. The human chorionic gonadotropin (hCG) (mimicking the Luteinising Hormone (LH)peak to trigger ovulation) that induces OHSS is replaced by an a GnRH agonist (GnRHa) triggering allowing an endogenous peak of Follicle Stimulating Hormone (FSH) and LH. Then, the usual support of the luteal phase by exogenous vaginal progesterone, whose absorption seems to be suboptimal for about 30% of patients, is replaced by endogenous progesterone production by the corpora lutea, supported by the maintenance of LH activity through the continuation of agonist of gonadotropin releasing hormone (AgoGnRH) in the luteal phase. Pilot studies show that a 10% to 15% increase in ongoing pregnancy rates can be expected with this type of protocol. The objective of our study is to demonstrate an increase in ongoing pregnancy rate per cycle with this new strategy combining GnRHa triggering and GnRHa luteal phase support compared to the reference protocol (hCG triggering and exogenous progesterone luteal phase support).