What is the optimal timing of embryo transfer when there are only one or two embryos at cleavage stage?
Today, most IVF programs have moved to blastocyst transfer but there is still uncertainty regarding when to transfer if there are only one or two embryos at the cleavage stage. The aim of this study was to compare the pregnancy rate of day 3 transfers vs. blastocyst stage transfers in patients who had only one or two embryos on day 3. We conducted a retrospective study of 102 patients with one or two cleavage stage embryos that had their embryos transferred on day 3 and 429 patients had their embryos cultured to day 5 for transfer. The number of mature oocytes (4.0 vs 4.6, p = NS) and number of cleavage stage embryos on day 3 was similar in the two groups (1.3 vs. 1.5, p = NS). The clinical pregnancy rate per retrieval (22% vs. 24.6%, p= NS) and the ongoing pregnancy rate per retrieval (20% vs. 20.2%, p = NS) was comparable between the groups. Fifty seven (13.2%) of the patients had cleavage embryo arrest and did not have an embryo to transfer on day 5. We conclude that the cumulative pregnancy rate is the same for patients with 1-2 cleavage stage embryos regardless of whether the embryo is transferred on day 3 or day 5.
['Haas|Jigal|J|', 'Meriano|Jim|J|', 'Bassil|Rawad|R|', 'Barzilay|Eran|E|http://orcid.org/0000-0001-5496-4866', 'Casper|Robert F|RF|']
D000328:Adult D001757:Blastomeres D002970:Cleavage Stage, Ovum D015331:Cohort Studies D004624:Embryo Transfer D004622:Embryo, Mammalian D005260:Female D006801:Humans D011247:Pregnancy D018873:Pregnancy Rate D059285:Pregnancy, Twin D012189:Retrospective Studies D056826:Single Embryo Transfer D013997:Time Factors D014427:Twins
Cleavage stage blastocyst stage embryo transfer timing