Effect of length of controlled ovarian hyperstimulation using a gonadotropin-releasing hormone antagonist on in vitro fertilization pregnancy rates.

Objective: To compare pregnancy outcomes between shorter and longer in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) cycles using GnRH antagonist protocol.

Study Design: Retrospective cohort analysis at a large military academic hospital. A total of 351 patients underwent 412 IVF/ICSI cycles using a GnRH antagonist protocol from September 2002 through May 2008. Clinical pregnancy and live birth rates for all IVF/ICSI cycles were compared independently for both total length of ovarian stimulation with gonadotropins (< 10 days vs. > or = 10 days) and GnRH antagonist use (< 4 days vs. > or = 4 days), respectively.

Results: Clinical pregnancy rates were 54.6% among cycles with total gonadotropin use <10 days vs. 48.6% for those cycles > or = 10 days, odds ratio 0.82 (0.53-1.27); live birth rates were 50.0% vs. 47.7%, odds ratio 0.91 (0.59-1.42). Clinical pregnancy rates were 54.0% among cycles with GnRH antagonist use < 4 days vs. 52.8% with GnRH antagonist use > or = 4 days, odds ratio 0.95 (0.62-1.45); live birth rates were 46.8% vs. 50.4%, odds ratio 1.15 (0.76-1.76).

Conclusion: Clinical pregnancy and live birth rates are not adversely affected by longer IVF/ICSI cycles using GnRH antagonists.