cepia

<p><b>OBJECTIVE: </b>To determine the prognostic impact of the embryo nuclear status at day 2 among other major morphologic parameters (first cleavage at day 1, number of blastomeres and anuclear fragmentation at day 2) on the birth rate.</p><p><b>DESIGN: </b>Retrospective study.</p><p><b>SETTING: </b>Hospital IVF department.</p><p><b>PATIENT(S): </b>Women undergoing 1,629 day 2 transfers of 2,732 embryos from May 2006 to November 2008.</p><p><b>INTERVENTION(S): </b>Four groups according to the embryo nuclear status.</p><p><b>MAIN OUTCOME MEASURE(S): </b>Implantation, miscarriage, and birth rates.</p><p><b>RESULT(S): </b>Univariate analysis indicated significantly higher birth rates when all blastomeres were mononucleated (15.0%) compared with embryos with not all blastomeres mononucleated (9.2%), embryos without any visible nucleus (7.7%), and embryos where at least one blastomere was multinucleated (4.2%). Multivariate analysis found significant decreased birth rates when multinucleated blastomeres were observed.</p><p><b>CONCLUSION(S): </b>Blastomere nuclear status should be added to the kinetic and morphologic criteria traditionally used at day 2 to assess human embryo quality. The presence of multinucleated blastomeres has a negative impact on birth potential. The results argue for integrating the blastomere nuclear status at day 2 with the kinetic and morphologic criteria traditionally used to define the best embryo to transfer. Embryos with a single visible nucleus in all blastomeres should be given priority for transfer when available.</p>