LAUSR

OBJECTIVE To study the true prevalence of recurrent implantation failure. DESIGN Retrospective cohort study. SETTING A private assisted reproductive technology center. PATIENT(S) Women (n = 4,429) with anatomically normal uterus who underwent up to three consecutive frozen euploid single embryo transfers (FE-SETs) were included in the study. Cycles with donor eggs or gestational carriers were excluded. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Cumulative outcomes from these cycles were analyzed. A logistic regression model was used to assess the differences of outcomes between first, second, and third FE-SET and a Kaplan-Meier curve as used to analyze cumulative implantation rate. RESULT(S) The mean age of the patients included in the study was of 35.4 years. The sustained implantation rates of the first, second, and third FE-SET were 69.9%, 59.8%, and 60.3% per transfer, respectively. The cumulative sustained implantation rate after up to three consecutive FE-SET was 95.2%. The live birth rates after the first, second, and third FE-SET were 64.8%, 54.4%, and 54.1% per transfer, respectively. The cumulative live birth rate after up to three consecutive FE-SET was 92.6%. The miscarriage rate after observing a positive heartbeat was not different between the first (7.2%), second (8.8%), and third (12.7%) FE-SET. CONCLUSION(S) Our findings suggest that true recurrent implantation failure is rare. For those patients with the ability to make euploid blastocysts, <5% would fail to achieve a clinical pregnancy with three embryos transferred. It remains to be further investigated whether this threshold identifies a truly recalcitrant group or simply a statistical certainty based on random variation.