Live Birth Rate After Transfer of a Single Euploid Blastocyst With and Without a Multinucleated Embryo

Multinucleation, a deviation from typical embryonic development, is frequently observed during in vitro fertilization (IVF) cycles. The relationship between multinucleation at the two-cell stage (2MN), chromosomal status, and live birth remains poorly defined.

This study aimed to investigate whether 2MN is associated with chromosomal status, determined by preimplantation genetic testing for aneuploidy (PGT-A), and live birth outcomes following single embryo transfer.

This prospective study, conducted from January 2023 to December 2023, included 152 patients undergoing IVF. Oocytes were cultured and monitored in a time-lapse system, and blastocysts were analyzed by PGT-A.

23.3% of embryos exhibited 2MN. Euploidy rates were significantly lower in the 2MN group (36.0%) compared to the non-multinucleation group (46.3%) (p < 0.05), and mosaicism was significantly more frequent in the 2MN group (42.6% vs. 31.1%, p < 0.05). However, live birth rates following euploid embryo transfer did not differ significantly between the non-multinucleation group (61.8%) and the multinucleation group (62.3%) (p > 0.05).

While 2MN is associated with reduced euploidy rates and increased mosaicism, euploid embryos with early multinucleation have comparable live birth rates to non-multinucleated embryos. A limitation of the study was the relatively small sample size for the live birth outcome subgroup.