A comparison of live birth rates and cumulative ongoing pregnancy rates between Europe and North America after ovarian stimulation with corifollitropin alfa or recombinant follicle-stimulating hormone.

To compare live birth rates after fresh embryo transfer (ET) and cumulative ongoing pregnancy rates after fresh ET and frozen-thawed (ET) between continents and overall after one treatment cycle with corifollitropin alfa or recombinant FSH.Double-blind, multicenter, randomized controlled trial.Fourteen centers in North America (NA); 20 in Europe (EU).804 NA patients and 702 EU patients.Patients >60 kg received a single dose of corifollitropin alfa or daily rFSH for the first 7 days of controlled ovarian stimulation.Live birth rates.Within each continent no differences were noted between the two treatment groups; however, between continents, the cumulative ongoing pregnancy rate and live birth rate were considerably higher in NA than in EU. The live birth rate in NA was 39.2% in both treatment groups compared with 31.5% and 28.8% in EU after corifollitropin alfa and rFSH treatment, respectively. Considering the number of embryos transferred, the live birth rate per ET was still higher in NA than in EU (42.7% v.s 36.8% with corifollitropin alfa and 41.6% vs. 30.9% with rFSH). Overall live birth rates after fresh ET were 35.6% and 34.4% (estimated difference 1.1% [95% confidence interval -3.7-5.8]), and the estimated cumulative live birth rates were 43.4% and 41.3% with corifollitropin alfa and rFSH, respectively.Live birth rates and cumulative pregnancy rates were higher in NA than in EU after treatment with either corifollitropin alfa or daily rFSH; both treatment protocols provided equal success rates. CLINICALTRIALS.GOV IDENTIFIERS: NCT00703014 and NCT00702273.