Association of embryo transfer catheter maneuvers on clinical pregnancy and live birth

To investigate the association between embryo transfer (ET) catheter maneuvers on clinical pregnancy (CP) and live birth (LB).

This retrospective cohort study included all in vitro fertilization and intracytoplasmic sperm injection cycles resulting in fresh or frozen ET at a single academic institution from 2013 to 2024. Catheter maneuvers were categorized as non-afterload or afterload. Non-afterload techniques included direct (straight outer sheath and inner catheter inserted together without manipulation), outer sheath curved, outer sheath extended, and outer sheath both curved and extended. Afterload techniques included: straight afterload (outer sheath retained, inner catheter removed, embryo loaded through another inner catheter), and curved afterload (curved outer sheath retained, inner catheter removed, and embryo loaded through another inner catheter). Adjusted log binomial regression assessed associations between ET catheter maneuvers and CP and LB.

Among 7882 ETs, 46.0% were direct, 1.9% curved, 8.8% extended, 10.2% curved and extended, 6.7% straight afterload, and 26.5% curved afterload. Afterload ETs were associated with lower adjusted relative risk (aRR) of CP (aRR 0.91, 95% confidence interval [CI] 0.85-0.98) and LB (aRR 0.88, 95% CI 0.81-0.96) compared to a direct technique. Curved afterload ETs had a lower aRR of both CP (aRR 0.91, 95% CI 0.85-0.98) and LB (aRR 0.92, 95% CI 0.86-0.99). Straight afterload ETs were associated with lower LB (aRR 0.89, 95% CI 0.81-0.99), but not CP (aRR 0.93, 95% CI 0.85-1.02). Non-afterload variations were not associated with outcome differences.

ET afterload techniques are associated with lower CP and LB rates compared to a direct technique.