Embriones multinucleados: criterios para la transferencia

Introduction

Multinucleation is a common phenomenon in in vitro human embryos and is associated with a poor outcome. Time-lapse monitoring of embryo development allows a continuous and detailed observation of fertilisation and cleavage events. An evaluation is presented on the impact of the presence of multinucleation on embryo morphokinetics, developmental ability, and implantation potential.

Material and methods

A retrospective cohort study was conducted on a total of 5540 embryos cultured in a TL system (Embryoscope®, Unisense Fertilitech®) from 763 ICSI cycles performed between 2012 and 2014. Presence of multinucleation in all developmental stages was assessed. Embryo replacement was performed on D + 3. Multinucleated embryos were cultured to the blastocyst stage and cryopreserved for subsequent transfer.

Results

Approximately one quarter (23.6%) of the studied embryos showed multinucleation. Multinucleated embryos showed altered morphokinetic parameters compared to the non-multinucleated ones. The multinucleated embryos that reached the blastocyst stage (18%) were cryopreserved. No differences in the developmental ability were observed compared to the multinucleated type or percentage of multinucleated cells. There was a 39.1% implantation rate of the blastocysts obtained from multinucleated embryos.

Discussion

Time-lapse monitoring of embryo development allows a better detection of the multinucleation phenomenon. The presence of multinucleated cells is associated with changes in the morphokinetics and a reduced developmental ability. However, multinucleated embryos that reach the blastocyst stage can be replaced, and have a high implantation potential.