6533b81ffe1ef96bd12787c3

RESEARCH PRODUCT

Limited implantation success of direct-cleaved human zygotes: a time-lapse study.

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Objective To evaluate embryos with direct cleavage (≤5 hours) from two to three cells (DC2–3) and correlate this morphokinetic parameter to implantation and ongoing pregnancy. Design Clinical multicenter retrospective study. Setting Private in vitro fertilization (IVF) centers. Patient(s) From three clinics, a total of 979 treatments including 5,225 embryos using autologous or donated oocytes, of which 1,659 embryos were transferred. Intervention(s) None. Main Outcome Measure(s) Clinical pregnancy confirmed by ultrasound in week 7. Result(s) Of the total embryo cohort, 715 (13.7%) underwent direct cleavage from two to three cells, 1,659 embryos were transferred to recipients, and 109 of the transferred embryos cleaved directly from two to three cells (6.6%). Only one DC2–3 embryo was known to result in a clinical pregnancy (1%) and 80 (73.4%) DC2–3 embryos did not implant. Of the 1,550 embryos transferred not showing DC2–3, 203 embryos were from treatments with 100% implantation (13.1%), and 804 (51.8%) embryos did not implant. The known implantation rate of DC2–3 embryos was statistically significantly lower than for embryos with a normal cleavage pattern (1.2% vs. 20.2%, respectively). Conclusion(s) Embryos with DC2–3 had a statistically significantly lower implantation rate than embryos with a normal cleavage pattern, suggesting that rejection of these embryos for transfer could improve the implantation rate.