Multinucleation in the early human cleavage-stage embryo in vitro is associated with reduced pregnancy rate and an increased number of abortions

Purpose Blastomere multinucleation of cleavage-stage embryos is defined as the presence of more than one visible nucleus per blastomere at a given time point during early embryonic development in vitro. Multinucleation has been associated with decreased blastulation and implantation rates following ART-treatments. Here we investigate early embryonic multinucleation assessed utilizing the EmbryoScope^TM time-lapse monitoring system (TMS) and its effect on ongoing pregnancy rates in our IVF-program.

Material and Methods In a retrospective observational study multinucleation at ESHRE / ALPHA consensus-proposed embryo evaluating times was detected in cleavage-stage embryos with our TMS. Transfers were grouped according to the percentage of multinucleated blastomeres during 2-cell-stage (50 % vs. 100 %); transfers without multinucleated embryos served as controls.

Results Multinucleation was detected in 384 of 1804 embryos designated for transfer in 1062 IVF / ICSI cycles. In double-embryo-transfers patients with multinucleated embryos displayed a significantly lower pregnancy rate (35.2 % vs. 48.4 %, p = 0.0076) and higher abortion rate (40.5 % vs. 25.7 %, p = 0.0003) compared to controls. The same effect was observed in single-embryo-transfers (pregnancy-rate: 10.8 % vs. 27.2 %, p = 0.0004)

Conclusion Blastomere nuclear formation is a dynamic process and the occurrence of multinucleation in 2-cell-stage human embryos seems to have a profound effect on implantation and ongoing pregnancy rate. Monitoring this parameter with a TMS for non-invasive pre-selection of embryos with lower developmental potential offers a clear advantage over conventional assessment of embryo morphology at given time points. Excluding multinucleated embryos from transfer were possible may also allow for decreased abortion rates.

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Artikel online veröffentlicht:
07. Oktober 2020