P-695 Optimizing oocyte donor stimulation: A revelation from 2,666 cases emphasizing the sole efficacy of exogenous FSH
Authors: Aparicio Ruiz B , Bori L , Carrion L , Varela M  Á , Bellver J , Meseguer M 
Published: July 2024

Abstract

Study question
Does the administration of human menopausal gonadotrophin in controlled ovarian stimulation improve clinical outcomes in the oocyte donation program?

Summary answer
The addition of hMG (human menopausal gonadotropin) reduces the number of retrieved oocytes without improving embryo development or clinical outcomes in oocyte donation program.

What is known already
In controlled ovarian stimulation for assisted reproduction treatments, follicle stimulating hormone(FSH) is essential, but the importance of LH supplementation from menopausal origin is controversial. It is a common practice to use hMG to provide the LH effect. The standard preparation contains FSH and LH effects in a 1:1 ratio.The FSH component would recruit ovarian follicles and stimulate their growth, while the LH component would facilitate their maturation. Our aim was to compare the outcomes of intracytoplasmic sperm injection (ICSI) treatments using a gonadotropin-releasing hormone GnRH) antagonist protocol with recombinant FSH(FSHr) alone and supplemented with hMG in the oocyte donation program.

Study design, size, duration
This is a retrospective cohort study of 2,666 patients enrolled in the oocyte donation program at a single center over four consecutive years. Donor stimulation commenced with daily FSHr injections. The FSHr group (n = 2,078) continued FSHr, while the FSHr+hMG group (n = 588) received hMG.

Participants/materials, setting, methods
Donors received GnRH agonist via i.m. injection until a mean diameter &gt;18 mm in at least eight follicles. Transvaginal oocyte retrieval was scheduled 36h later, followed by ICSI for all retrieved oocytes. Embryos were cultured in time-lapse systems and evaluated using an artificial intelligence-based model (iDAScore v2). Recipients underwent hormone replacement therapy for endometrial preparation. Our comparative study examined oocytes retrieved, embryo score, implantation, and live birth outcomes in fresh and frozen embryo transfers (ETs).

Main results and the role of chance
The number of retrieved oocytes was higher in the FSHr group than in the FSHr+hMG group: 24.9±10.6 vs. 18.2±8.8 (p &lt; 0.001). In addition, embryos from the FSHr+hMG group exhibited slower early development, with significantly lower division times to two, three, four and five cells in the FSHr group (p &lt; 0.005). However, late parameters of embryo development showed no differences. Automatic scoring by the deep learning algorithm was identical for blastocysts in the FSHr (4.8±2.8) and FSHr+hMG groups (4.8±2.8); p = 1. Implantation rates showed no significant differences for fresh ET (FSHr: 58.6% vs. FSHr+hMG: 61.9%; n = 2,073; p = 1) or frozen ET (FSHr: 49.3% vs. FSHr+hMG: 46%; n = 2,687; p = 1). Similarly, there were no differences in live birth rates for fresh ET (FSHr: 45.6% vs. FSHr+hMG: 50.3%; n = 1,993; p = 1) or frozen ET (FSHr: 31.8% vs. FSHr+hMG: 33.8%; n = 2,508; p = 1).

Limitations, reasons for caution
The retrospective and single-center nature of the study would be its main limitations. It is essential to emphasize that these results are only applicable within the oocyte donation program.

Wider implications of the findings
Based on our findings, the use of exogenous FSHr alone is likely adequate in the GnRH antagonist protocol for optimal ovarian stimulation of donors, leading to the production of high-quality embryos and successful clinical outcomes.

Trial registration number
Not Applicable