Evaluation of embryo transfer time (day 2 vs day 3) after imposed single embryo transfer legislation: when to transfer?

To determine whether the timing of embryo transfer (day 2 or day 3) affects pregnancy outcome in IVF patients, receiving single or double embryo transfer, 380 patients were included in this retrospective study. All patients underwent GnRH antagonist protocol. When stratified by number of transferred embryos, single embryo transfer (SET) patients undergoing a day 2 embryo transfer (ET) had similar biochemical pregnancy (25% vs 20.4%; p > 0.05) and clinical pregnancy (16.6% vs 14.6%; p > 0.05) rates to SET patients that were undergoing a day 3 ET. A similar observation was again noted in double embryo transfer (DET) patients undergoing a day 2 ET, with similar biochemical pregnancy (35% vs 29.8%; p > 0.05) and clinical pregnancy (25% vs 15.5%; p > 0.05) rates to DET patients undergoing a day 3 ET. Women, despite age, number of transferred embryos and ET timing, have similar reproductive outcomes. Shortening or lengthening the duration of in vitro culture provides no obvious benefit.