Pirtea · Fertility and sterility 2021 · retrospective cohort study · n=4,429

Rate of true recurrent implantation failure is low: results of three successive frozen euploid single embryo transfers.

Cited 203 times in the scientific literature.

Level 3 - non-randomized controlled study

Non-randomized retrospective cohort study

PubMed 33077239 · doi:10.1016/j.fertnstert.2020.07.002 · record verified 2026-08-26

What was done

Retrospective cohort study of 4,429 women (mean age 35.4 years) with an anatomically normal uterus undergoing up to three consecutive frozen euploid single embryo transfers (FE-SETs) at a private assisted reproductive technology center. Donor egg and gestational carrier cycles were excluded. Cumulative sustained implantation and live birth rates across cycles were evaluated using logistic regression and Kaplan-Meier analysis.

What was found

Sustained implantation rates per transfer were 69.9% (first), 59.8% (second), and 60.3% (third), yielding a cumulative sustained implantation rate of 95.2% after up to three transfers. Per-transfer live birth rates were 64.8%, 54.4%, and 54.1%, resulting in a cumulative live birth rate of 92.6%. Miscarriage rates after a positive fetal heartbeat did not differ significantly between cycles (7.2%, 8.8%, and 12.7%, respectively).

Why it matters

These data demonstrate that for patients capable of producing euploid blastocysts, true recurrent implantation failure is rare, with fewer than 5% failing to achieve sustained implantation after three consecutive transfers.

Limits

Retrospective design from a single private fertility center. Findings are conditional on generating multiple euploid blastocysts, selecting for a favorable prognosis group, and the abstract does not report specific endometrial preparation protocols or reasons for patient attrition between cycles.

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