P-598 Analysis of the oocyte yield and Ovarian Sensitivity Index with the use of two gonadotropins (FSHr/FSHu) and two pituitary suppression protocols (PPOS/GnRH-ant)
Authors: Bontá S , Forgiarini A , Maggi S , Lammens G , Navarro I , Burguera A , Quintero Espinel L A 
Published: June 2023

Abstract

Study question
Is there a difference, in terms of ovarian yield and sensitivity, comparing a progestin-primed protocols (PPOS) to a GnRH antagonist (GnRH-ant) and using different follitropin?

Summary answer
PPOS is an effective choice, with both follitropis. Nevertheless, could improve ovarian sensitivity to FSHu increasing the number of oocyte yield without compromising oocyte quality.

What is known already
The use of new ovarian stimulation protocols, starting during the luteal phase or randomly shows that endogenous progesterone alone is sufficient to block the LH surge and does not compromises oocyte competence and pregnancy outcomes. For these reasons, exogenous progesterone was utilized as an innovative model of pituitary suppression. Most studies have shown the effectiveness of the use of PPOS compared to the GnRH (antagonist or agonist) in IVF cycles. For oocyte donation only three studies were carried out analyzing the effect of PPOS with a recombinant FSH (FSHr)

Study design, size, duration
It is a retrospective, cohort, paired study. We analyzed egg donation cycles carried out in Next Fertility Valencia from January 2020 to May 2021. In total 93 donors were selected as eligible, each one undergoing both the PPOS and GnRH antagonist cycles for a total of 186 cycles, 54 received FSHr and 39 HP-FSHu. To attempt to eliminate possible bias due to interpersonal differences, every patient was her own control.

Participants/materials, setting, methods
All donors underwent two controlled ovarian stimulation cycles within 6 months, one using flexible GnRH antagonist (Ganirelix) and the other using medroxyprogesterone acetate (MPA), with FSHr or FSHu monotherapy and a GnRH-agonist triggering. The oocyte yield was analyzed focusing on: the number of oocytes retrieved, mature (MII) oocytes and useful oocytes (mature oocytes without morphological alterations). We also evaluated the Ovarian sensitivity index (OSI) calculating the oocyte number for each 1000 IU of gonadotropin used

Main results and the role of chance
Total gonadotropin consumption and duration of ovarian stimulation were similar in both models of pituitary suppression regardless the type of FSH. One less control is required with MPA than the GnRH-ant in both FSH groups. There were no premature ovulations in MPA or GnRH antagonist cycles regardless of the gonadotropin used. In the FSHr group no difference was observed in the oocyte yield and OSI between MPA and GnRHa. On the other hand, in the FSHu group a statistically significant improvement in the number of total oocytes retrieved (20,2 ± 8,5 vs 23,8 ± 10,9), total MII (18,0 ± 7,2 vs 21,2 ± 10,4) and OSI (6,4 ± 3,5 vs 7,7 ± 4,6) was observed in favor of the use of MPA. Also, the number of useful MII was higher with MPA (15,7 ± 6,5 vs 18,6 ± 10,4). No significant differences were detected in fertilization and blastocyst rate regardless the type of pituitary suppression and FSH used

Limitations, reasons for caution
The main limitation lies in the retrospective nature of the study. However, since each patient is her own control (Paired study), it gives an added value

Wider implications of the findings
The efficacy and efficiency of the MPA does not seem to be affected by the type of gonadotropin used, this further reassures about the possibility of using it with patients in case of fertility preservation cycles, PGT-A/M, "DuoStim" cycles

Trial registration number
Not applicable