Recurrent implantation failure: how common is it?

PURPOSE OF REVIEW: To clarify a lingering issue, the true incidence of repeated implantation failures (RIF) in women undergoing successive frozen euploid single embryo transfers (FE-SET). RECENT FINDINGS: As not all Assisted reproductive techinique (ART) attempts are crowned by success, it has been questioned since incept of ART whether failures resulted from an embryonic or endometrial cause. RIF has received no precise definition but a trend has existed toward setting a more stringent definition, as reproductive biology has become more effective and ART success rates improved. No scientific society has yet convened on a universally accepted definition. The advent of effective and well tolerated pregestational testing of embryos for aneuploidy (PGT-A) has allowed to not transfer aneuploid embryos, which are bound not to succeed. This, therefore, justify revisiting the concept of RIF when only euploid embryos are transferred. SUMMARY: Contrary to lingering beliefs, the results of our study indicate that RIF following three successive euploid embryo transfers in a morphologically normal endometrium is a rare occurrence (<5%). This supports the concept that ART failures mainly result from embryonic causes. Our data also propose a new - functional - definition of RIF being an ART failure following 3 successive FE-SET attempts. Our findings, therefore seriously question the soundness of prescribing the often complex and expensive endometrial testing procedures that largely publicized for treating RIF.

B-cell lymphoma 6 expression is not associated with live birth in a normal responder in vitro fertilization population.

OBJECTIVE: To determine whether increased endometrial B-cell lymphoma 6 (BCL6) expression is associated with live birth in a normal responder in vitro fertilization (IVF) population. DESIGN: Case-control study. SETTING: University-affiliated infertility center. PATIENT(S): Two groups of women undergoing IVF with preimplantation genetic testing for aneuploidy followed by warmed, single, euploid embryo transfer. Group 1 consisted of women who failed to achieve live birth, and group 2 consisted of women who achieved live birth. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Endometrial BCL6 expression measured by immunohistochemistry in endometrial tissue samples. Overexpression was defined by mean HSCORE with a cutoff of positivity of >1.4, as previously described in the literature. RESULT(S): Twenty-seven patients who achieved live birth and 23 patients who failed to achieve live birth were included. B-cell lymphoma 6 expression/HSCORE and live birth rate were not associated (Odds ratio [OR], 0.78 [0.24-2.55]). Using a cutoff of >1.4 for positivity, 8 of 23 samples were positive for BCL6 in the no live birth group, whereas 7 of 27 were positive in the live birth group. There was no significant association between BCL6 positivity and live birth (OR, 0.66 [0.19-2.21]). CONCLUSION(S): The proportion of patients with BCL6 positivity did not significantly differ between those who achieved live birth and those who did not. In the population of patients at our center, who compromise of women who respond normally to IVF stimulation, BCL6 overexpression was not associated with IVF success. Physicians implementing BCL6 testing as a diagnostic tool for clinical decision making should counsel patients that results may have limited utility in predicting IVF outcomes in this population.