Triggering of Final Oocyte Maturation with Gonadotropin-releasing Hormone Agonist or Human Chorionic Gonadotropin. Live Birth After Frozen-thawed Embryo Replacement Cycles

Objective: To report the outcome of frozen-thawed embryo replacement cycles after GnRH-agonist triggering of final oocyte maturation in the collecting cycle with GnRH-antagonist.

Design: Prospective, observational, multicentric clinical study.

Setting: Tertiary university-affiliated IVF centers.

Patient(s): Patients under observation previously had been recruited into two concurrently performed, independent, randomized controlled trials (comparing hCG with GnRH-agonist for triggering final oocyte maturation in GnRH-antagonist multiple-dose protocols in normal responder patients) encompassing a total of 228 participants. Surplus embryos or oocytes at the pronuclear stage were cryopreserved in 53 patients after hCG administration and 32 patients after GnRH-agonist administration on the basis of patient choice, pronuclear/embryo availability, and local laws.

Intervention(s): Transfer of frozen-thawed embryos.

Main Outcome Measure(s): Live birth rate.

Result(s): Thirty-one and 23 patients after administration of hCG and GnRH-agonist, respectively, started a frozen-embryo replacement cycle by September 2005, with 25 and 16 patients eventually undergoing at least one frozen-thawed ET. Live birth rate per ET was 18.5% (95% confidence interval [CI], 8.2-36.7) and 30.0% (95% CI, 14.5-51.9) after hCG and GnRH-agonist triggering, respectively. Cumulative live birth rate per patient starting a frozen-embryo replacement cycle was 16.1% (95% CI, 7.1-32.6) and 26.1% (95% CI, 12.5-46.5) for hCG and GnRH-agonist, respectively.

Conclusion(s): The likelihood of live birth in frozen-embryo replacement cycles after GnRH-agonist triggering of final oocyte maturation does not appear to be impaired.