Progesterone rise after agonist trigger inprogesterone-primed stimulated cycles differs from antagonist cycles

Abstract

Progesterone-primed (PP) stimulated cycles are a safe and effective alternative to antagonist cycles for controlling the endogenous LH rise in any clinical situation in which endometrium receptiveness is not an issue, i.e. oocyte donors (OD). Some concern may exist regarding the quality of the endocrine response to the final oocyte maturation trigger when performed with a GnRH agonist bolus. The objective is to describe the endocrine response to GnRH agonist trigger in antagonist (ANT) versus PP stimulated cycles in OD. Retrospective OD underwent ovarian stimulation with gonadotropins at a private, university-based infertility clinic between Jan’17-Mar’18. Serum estradiol evaluation and ultrasound scans were performed for monitoring response. Endogenous LH peak was controlled with either daily injections of GnRH antagonist starting when leading follicle diameter ≥14 mm (ANT) or with daily oral 75mcg desogestrel (PP) from stimulation day 1 until trigger. When >3 follicles >18 mm were observed, patients were triggered with 0.2 mg of triptorelin and oocyte retrieval was performed 36 hours later. Serum LH and P were measured at trigger and the following day (trigger+1). Considering only recipients undergoing a fresh cycle and single embryo transfer, laboratory and clinical outcomes were analyzed. Wilcoxon Mann-Whitney test was used. A total of 404 OD cycles were included. There were no differences in mean age, AMH between groups. After agonist trigger, significantly lower serum P were observed in PP compared to ANT groups both at trigger and the following day. No differences were observed in serum LH levels. The average number of MIIs, fertilization rates and total number of usable embryos were also similar. OD treated with gonadotropins displayed significantly lower P before and after agonist trigger when oral desogestrel was used for the control of endogenous LH compared to the use of GnRH antagonist. It is hypothesized that differential endogenous LH inhibition during stimulation with a GnRH antagonist or PP could be associated to the different outcomes.Tabled 1Estradiol, progesterone and LH values on Triggering day and day after trigger, and cycle outcomesPP Group (n=207)ANT group (n=197)p-valueEstradiol at trigger (pg/ml)1939.1±1235.52065.3±1325.10.483Days of stimulation10.0±2.610.5±2.00.048Follicles at trigger19.7±6.119.9±7.00.984P4 at trigger0.9±0.71.5±1.2<0.001P4 at trigger+110.8±6.013.4±7.90.002LH at trigger0.9±0.90.7±0.70.146LH at trigger+130.2±22.134.3±24.70.071MII oocytes14.2±7.415.4±7.90.129Recipient Fresh cyclesn=106n=89Total Number of usable embryos5.1±2.25.1±2.20.925Clinical Pregnancy Rate72.6% (77/106)53.9% (48/89)0.007 Open table in a new tab