OBJECTIVETo analyze the clinical characteristics and cycle outcome of Chinese women with gonadotropin-releasing hormone (GnRH) antagonist treatment during controlled ovarian hyperstimulation (COH) for in vitro fertilization and embryo transfer (IVF-ET).

METHODSA retrospective review was conducted in patients who completed 54 consecutive cycles of IVF-ET with GnRH antagonist treatment for luteinizing hormone (LH) surge prevention. Descriptive statistics were recorded for the patients' age, GnRH treatment duration (days) and dose, timing and duration of GnRH antagonist treatment, serum E2 and LH level on the day of antagonist use and hCG injection, number of oocytes retrieved, and clinical pregnancy rate.

RESULTSThe clinical pregnancy rate was 46.2% per ET cycle for GnRH antagonist group and 56.8% in GnRH agonist group, showing no significant difference between the two protocols. The age of the patients with GnRH antagonist averaged 35.7-/+3.8 years. Gn and GnRH antagonist treatment lasted for 8.5-/+1.6 and 4.5-/+1.1 days, respectively. On the day of ovulation triggered by hCG, the serum estradiol level was 1616.7-/+721.1 pg/ml, and a mean of 7.4-/+4.6 oocytes was collected per retrieval. The number of the embryos transferred was 2.4-/+0.6, with an implantation rate of 27.7%, resulting in a clinical pregnancy rate of 50.0% in the fixed protocol (antagonist initiation on day 4 or 5 of stimulation) and 37.5% in the flexible protocol (antagonist treatment initiated for a follicle of 12-15 mm, on day 6 to 9 of stimulation).

CONCLUSIONSGnRH antagonists treatment results in good outcomes and can be safe, short, convenient and effective for Chinese women undergoing COH for IVF. GnRH antagonist treatment can be initiated on day 4 to 9 of Gn stimulation to obtain comparable pregnancy rate.