Comparison of Frozen-thawed Embryo Transfers and Fresh Embryo Transfers With Whole Chromosome Analysis Using Next Generation Sequencing

1. Fresh group: All embryos will be hatched on day 3. Patients will have hatching blastocysts (\*) biopsied on day 5, analyzed by NGS, and will have one or two euploid embryo transferred on day 6, in the am. If more than two euploid blastocysts are available the one(s) to be transferred will be selected based on morphology (\*). Any morulas developing to hatching blastocyst on day-6 will be also analyzed but vitrified for use in a future cycle. 2. Frozen group: All embryos will be hatched on day 3. Patients will have hatching blastocysts (\*) biopsied on day 5 or day 6, embryos will then be vitrified, analyzed by NGS, and will have one or two euploid embryo(s) thawed and transferred on a FET cycle, before noon. If more than two euploid blastocysts are available the one(s) to be transferred will be selected based on morphology (\*). (\*) Hatching blastocysts as described by Gardner and Schoolcraft (1999):