研究開発・学会発表

【要旨】

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 2 embryos on day 2 (two-step group). Ninety day-2 ET cycles were performed in age- and infertility-matched patients who had 2 embryos on day 2 (control group).
Intervention(s): Cleaved-embryo transfer, 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: Taking advantage of both day-2 ET and blastocyst transfer, two-step ET may be an effective option for embryo transfer in patients who have an insufficient number of embryos.
Key words: Two-step embryo transfer, blastocyst, poor responder