Journal Article

A prospective randomized study: day 2 versus day 5 embryo transfer

Ingrid Van der Auwera, Sophie Debrock, Carl Spiessens, Hilde Afschrift, Els Bakelants, Christel Meuleman, Luc Meeuwis and Thomas M. D'Hooghe

in Human Reproduction

Published on behalf of European Society of Human Reproduction and Embryology

Volume 17, issue 6, pages 1507-1512
Published in print June 2002 | ISSN: 0268-1161
Published online June 2002 | e-ISSN: 1460-2350 | DOI:
A prospective randomized study: day 2 versus day 5 embryo transfer

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BACKGROUND: This randomized controlled study was performed in an unselected IVF/ICSI population to test the hypothesis that blastocyst transfers result in higher clinical pregnancy rates (CPR) per oocyte retrieval when compared with day 2 transfers. METHODS: Blind randomization for transfer on day 2 (group 1) or day 5/6 (group 2) was performed before stimulation. Oocytes and embryos were cultured in sequential media in 5.5% CO2, 5% O2, 89.5% N2 and 90% humidity. A maximum of two embryos was transferred. RESULTS: The two groups were similar for age, IVF indication, number of treatment cycles, rate of ICSI/IVF, number of fertilized oocytes and number of embryos transferred. The CPR/oocyte retrieval was comparable in group 1 (32%) and in group 2 (44%), while the CPR/embryo transfer was significantly higher (P < 0.01) in group 2 (60%) than in group 1 (35%). Similarly, the implantation rate per embryo transferred was significantly higher (P < 0.03) in group 2 (46%) than in group 1 (29%). The cryo-augmented delivery rate/oocyte retrieval was comparable in group 2 (36.3%) and in group 1 (28.6%). CONCLUSION: This randomized study in an unselected population showed a significantly higher CPR/embryo transfer and a tendency toward a higher CPR/oocyte retrieval in patients receiving blastocysts when compared with day 2 transfers.

Keywords: blastocyst; embryo transfer; human; sequential media

Journal Article.  5306 words. 

Subjects: Reproductive Medicine

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