Endometrial BCL6 testing for the prediction of in vitro fertilization outcomes: a cohort study

Objective To evaluate endometrial BCL6 expression as a prognostic biomarker for IVF outcome in women with unexplained infertility (UI) before ET. Design Prospective cohort study. Setting University-associated infertility clinic. Patient(s) Women with UI for >1 year. Intervention(s) We studied women with UI who underwent testing for endometrial BCL6, in an LH-timed midluteal phase biopsy and completed an IVF cycle and ET. Main Outcome Measure(s) Clinical pregnancy rate (PR) and live birth rate per transfer was compared for women positive or negative for BCL6 expression. An abnormal BCL6 result was defined by an histologic score (>1.4). Result(s) Women with normal and abnormal BCL6 and those who conceived or not had similar characteristics. Women with low levels of BCL6 expression had a significantly higher clinical PR (11/17; 64.7%; 95% confidence interval [CI] 41.3–82.6) compared with women with abnormal (high) BCL6 expression (9/52; 17.3%; 95% CI 9.3–30.8). These results yield a relative risk of 0.267 (95% CI 0.13–0.53; P =.0004) for those with normal BCL6 expression, an absolute benefit of 47.4% (95% CI 22.5–72.0). Live birth rate was also significantly higher in women with low BCL6 expression (10/17; 58.8%; 95% CI 36.0–78.4) compared with women with abnormal BCL6 expression (6/52; 11.5%; 95% CI 5.4–23.0). The relative risk was 0.19 (95% CI 0.08–0.45; P =.0002), yielding an absolute benefit of 47.3% (95% CI 21.8–67.8). Conclusion(s) Aberrant BCL6 expression (histologic score, >1.4) was strongly associated with poor reproductive outcomes in IVF cycles in women with UI.