Hyaluronan-enriched transfer medium in routine clinical practice: a retrospective cohort study showing no improvement in pregnancy outcomes among predominantly frozen embryo transfer cycles

Abstract Purpose To evaluate the effect of hyaluronan-enriched transfer medium (HETM; EmbryoGlue) on clinical pregnancy rates in a predominantly frozen embryo transfer (FET) cohort and to identify independent predictors of outcome. Methods In this retrospective, nonrandomized cohort study, we analyzed 335 embryo transfer cycles at a university-based ART unit (June 2025–April 2026): HETM group (EmbryoGlue, n = 171) vs. control (Irvine NX medium, n = 164). Allocation to transfer medium was based on shared clinical decision-making. The primary outcome was clinical pregnancy rate per cycle. Multivariate logistic regression identified independent predictors. Results FET accounted for 87.5% of cycles. Overall clinical pregnancy rate was 56.7% (190/335). Rates were comparable between HETM and control groups (56.7% vs. 56.7%; OR = 1.00, 95% CI 0.65–1.54; p > 0.999). No statistically significant between-group differences were observed in exploratory subgroups, including women aged ≥ 35 years, cycles with two or more previous transfer attempts, and blastocyst transfers (all p > 0.05). Despite a higher proportion of cycles with two or more previous transfer attempts in the HETM group (41.5% vs. 27.4%; p = 0.008), HETM was not an independent predictor of pregnancy (OR = 0.89, 95% CI 0.55–1.46; p = 0.652). FET (OR = 4.32; p < 0.001), blastocyst-stage transfer (OR = 2.96; p < 0.001), and younger age (OR = 0.92 per year; p = 0.001) were independently associated with clinical pregnancy. Conclusions HETM use was not associated with higher clinical pregnancy rates in this cohort. Transfer type, embryo stage, and patient age were independently associated with clinical pregnancy. These findings do not provide evidence supporting the routine use of EmbryoGlue in unselected FET populations.