Influence of embryo sex on development to the blastocyst stage and euploidy.

Objective: To compare the prevalence of blastocyst development and euploidy in XX versus XY embryos.
Design: Retrospective cohort study.
Setting: Boston IVF, a large university-affiliated reproductive medicine practice.
Patient(s): All patients who underwent their first preimplantation genetic screening cycle between January 1, 2006, and December 31, 2007.
Intervention(s): In vitro fertilization and preimplantation genetic screening.
Main Outcome Measure(s): Proportion of embryos that developed to the blastocyst stage by day 5 and prevalence of euploidy for chromosomes 8, 13, 14, 15, 16, 17, 18, 20, 21, and 22 in XX versus XY embryos.
Result(s): Seven hundred fifty-eight embryos from 138 cycles in 138 patients were analyzed. Three hundred sixty-six (48%) were XX, and 392 (52%) were XY. XX and XY embryos were equally likely to develop to the blastocyst stage by day 5 and were equally likely to be euploid for the analyzed chromosomes.
Conclusion(s): Our data suggest that extending embryo culture to day 5 does not lead to sex selection and that euploidy and aneuploidy are not sex dependent.
(Copyright © 2011 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)