Objective: To compare oocyte maturity, fertilization rate and cleavage rate after a short and long GnRH agonist (GnRH-a) stimulation protocol and intracytoplasmic sperm injection (ICSI).
Design: Retrospective study of 34 sequential ICSI cycles stimulated with a short or long GnRH-a protocol.
Setting: A university-based tertiary care center for assisted reproductive treatment.
Results: Significantly more oocytes were mature (metaphase II) after a long GnRH-a protocol then after a short GnRH-a protocol (25.6% and 80.8%, respectively). The long protocol resulted in more cleaving embryos (36/152 versus 9/132) and more cycles of ET (12/17 versus 5/17) than the short group.
Conclusion: A greater percentage of mature oocytes results from ovarian stimulation with a long GnRH-a protocol than a short GnRH-a protocol. Maturity could be assessed accurately after cumulus stripping that is required before ICSI. Fertilization rate and cleavage rate with ICSI was superior after a long GnRH-a stimulation protocol for superovulation.