Significantly higher pregnancy rate after transfer of EEVA (Early Embryo Viability Assessment) positive embryos in fresh IVF / ICSI-cycles

Purpose Morphokinetic parameters of early human development as applied by the EEVA-test were suggested as positive predictive parameters for implantation. Here we validate the applicability of these parameters to our EmbryoScope^TM time-lapse monitoring system (TMS) in 1159 IVF / ICSI-cycles with hormonal stimulation, oocyte retrieval, intracytoplasmic sperm injection (ICSI) and day 3 or 5 embryo transfer.

Materials and methods In a retrospective observational study we analysed the time of cleavage from the 2- to the 3-cell stage (t3) and the duration of the 3-cell stage (t4-t3) of 1925 embryos designated for transfer and cultured in the EmbryoScope^TM. Patients were assigned either to the single-embryo-transfer-(SET) or double-embryo-transfer-(DET)-group. An embryo was considered EEVA-test-positive (EEVA+) if t3 occurred between 9-11 hours from the time of cleavage into the 2-cell stage (t2) and t4-t3 was under 2 hours.

Results In the SET group patients showed a significantly higher pregnancy rate if the transferred embryo was EEVA-positive (30.1 % vs 16.4 %, p = 0.0028). In the DET group pregnancy rate was significantly higher if at least one of the transferred embryos was EEVA positive (55.6 % vs 28.4 %, p ≤ 0.0001).

Summary The morphokinetic parameters t3 and t4-t3, as applied in the EEVA-test, are also highly predictive of implantation potential when analysed in the EmbryoScope^TM. The non-invasive identification of embryos with high implantation potential, as facilitated by TMSs, offers a clear advantage over the conventional evaluation of embryo morphology and may pave the way back to an early transfer approach at day 3 thus minimizing possible adverse effects of prolonged embryo culture.

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Publication History

Article published online:
07 October 2020