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Updated: Aug 30, 2026
Fertility Preservation Through Oocyte Vitrification: Clinical and Laboratory Perspectives
Published on: September 16, 2021
The use of gonadotropin-releasing hormone antagonist in a flexible protocol: a pilot study
Ragaa T Mansour1, Mohamed A Aboulghar, Gamal I Serour
1Egyptian IVF-ET Center, and the Department of Obstetrics and Gynecology, Cairo University, Cairo, Egypt. ivf@link.net
Objective:
The purpose of this study was to investigate the efficacy of a flexible protocol of starting gonadotropin-releasing hormone antagonist according to the size of the leading follicle.
Study Design:
This was a pilot study that included 123 couples who were undergoing in vitro fertilization/intracytoplasmic sperm injection cycles at the Egyptian IVF-ET Center. Couples were recruited into two groups: group I (n=64), gonadotropin-releasing hormone antagonist was administered when the diameter of the leading follicle reached 16 mm; group II (n=59), gonadotropin-releasing hormone antagonist was administered on day 6 of stimulation.
Results:
The mean number of antagonist injections was significantly lower in the flexible protocol compared to the fixed protocol (3.4+/-1.1 vs 5.3+/-1.8, P<.05). There was no significant difference between the two protocols regarding the number of embryos, implantation rate, clinical pregnancy rate (odds ratio, 0.85; 95% CI, 0.45-1.59) or multiple pregnancy rate (odds ratio, 1.26; 95% CI, 0.45-3.51).
Conclusion:
Starting the gonadotropin-releasing hormone antagonist according to the size of the leading follicle is as effective as starting on a fixed day and reduces the antagonist administration.
