Related Experiment Video
Updated: Jul 4, 2026
Fertility Preservation Through Oocyte Vitrification: Clinical and Laboratory Perspectives
Published on: September 16, 2021
GnRH agonist long protocol vs. a single 3-mg gnRH antagonist: a comparison of 2 protocols for pituitary
Teresa M Erb1, Anthony N G Wakim
1Reproductive Endocrinology and Infertility, University of Pittsburgh Physicians, Pittsburgh, Pennsylvania 15213, USA. erbtm@msx.upmc.edu
Objective:
To compare ovarian stimulation outcomes for 2 protocols of pituitary down-regulation in a group of fertile women.
Study Design:
Retrospective outcome analysis of 35 healthy oocyte donors participating in a university-affiliated in vitro fertilization donor program from 1999 to 2004. Consecutive donor cycles were grouped according to the agent used for down-regulation (n = 27 GnRH agonist, n = 31 GnRH antagonist). Statistical analysis was performed using ANOVA, chi2 and Wilcoxon Rank Sum tests.
Results:
Neither gonadotropin dosage, days of stimulation or number of oocytes retrieved per treatment cycle were statistically different between groups. The only significant embryo quality parameter was more grade D embryos in the GnRH antagonist (0.4 +/- 0.6) vs. GnRH agonist arm (0.0 +/- 0.2). The number of embryos transferred was significantly greater for the GnRH agonist (2.7 +/- 0.5) than GnRH antagonist arm (1.0 +/- 0.5), whereas implantation and clinical pregnancy rates were not significantly different between groups. No patient experienced the ovarian hyperstimulation syndrome.
Conclusion:
Since there was no significant difference in the biologic effects of the 2 protocols, the use of a 3-mg GnRH antagonist for down-regulation in a donor program is preferable to the long protocol because it requires only 1-2 injections for pituitary down-regulation.
Related Concept Videos
01:30Hormonal Control of the Ovarian Cycle
Before puberty, the hypothalamus releases GnRH in a low frequency, low amplitude pulsatile manner. This along with the immature hypothalamic-pituitary-gonadal axis activity, results in low estrogen levels and the absence of a fully functional ovarian cycle. At puberty, GnRH secretion increases in both frequency and...
01:22Hormonal Regulation of the Menstrual Cycle
At puberty, GnRH begins a pulsatile release pattern, which triggers the anterior pituitary gland to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The frequency and amplitude of GnRH pulses vary across the menstrual cycle, with faster pulses favoring LH release and slower pulses favoring FSH release.