Effectiveness of two-step (consecutive) embryo transfer in patients who have two embryos on day 2: comparison with cleavage-stage embryo transfer

Objective: To evaluate the effectiveness, for patients who have only two embryos on day 2, of a two-step (consecutive) embryo transfer (ET) procedure in which a cleaved embryo is transferred on day 2 and a single blastocyst is transferred on day 5. Design: Observational comparative study. Setting: Private IVF clinic. Patient(s): Ninety two-step ET cycles were performed in patients who had two embryos on day 2 (two-step group). Ninety day-2 ET cycles were performed in age- and infertility-matched patients who had two embryos on day 2 (control group). Intervention(s): Cleaved-ET, extended culture of one embryo, and a second transfer of a blastocyst. Main Outcome Measure(s): Implantation and pregnancy rates. Result(S): The pregnancy and implantation rates in the two-step group (respectively 33.3% and 17.2%) were significantly higher than those in the control group (18.9% and 9.4%). Thirty-nine of the patients in the two-step Group (43.3%) could not proceed to the second step of ET because no viable'blastocyst could be obtained, but four of them conceived anyway. Conclusion(s): Taking advantage of both day-2 ET and blastocyst transfer, two-step ET may be an effective option for ET in patients who have an insufficient number of embryos. (c) 2005 by American Society for Reproductive Medicine.