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Updated: Jul 15, 2026
Collection of Human Follicular Fluid, Follicle Somatic Cells, and Immature Oocytes from Individuals Undergoing In Vitro Fertilization
Published on: October 24, 2025
Blastocyst Morphology in Oocyte Donors stimulated During the Late Follicular Phase with either rFSH:rLH or HP-hMG in
Fiorella Castillo-Velásquez1,2, Silvia Ortiz1,2, Paula Ricra1
1Grupo PRANOR, Lima, Peru.
Objective:
The aim of this study was to investigate whether there were differences in the number of good-quality blastocysts after 6 days of treatment with r-hFSH followed by late follicular phase treatment with r-hFSH:r-hLH in a 2:1 fixed ratio combination or HP-hMG in a PPOS protocol in a population of young women.
Methods:
Healthy oocyte donors were randomized to Group 1 or Group 2 (40 women per group). All donors were treated with 200 mg/day oral progesterone from Day 1 and 225 IU/day r-hFSH for the first six days of ovarian stimulation. From Day 7 onwards, Group 1 received 225 IU/day r-hFHS:r-hLH 2:1 fixed ratio combination and Group 2 received 225 IU/day HP-hMG. Insemination was performed using intracytoplasmic sperm injection. Embryo quality was graded using the SART classification. The primary outcome was the number of blastocysts with good morphology (AA or AB).
Results:
The mean (SD) number of good-quality blastocysts was significantly higher in Group 1 compared with Group 2 (3.4 [2.0] vs. 2.3 [2.0]; difference 0.9 (0.6 to 1.7); Kruskal-Wallis test p=0.0359). There was no difference in total gonadotropin dose, length of stimulation or number of oocytes retrieved between the groups.
Conclusion:
Treatment with r-hFSH:r-hLH in a 2:1 fixed ratio combination starting in the late follicular phase resulted in a significantly higher number of good-quality blastocysts compared with HP-hMG in oocyte donors receiving PPOS.
