Evaluation of the introduction of a new assisted vaginal birth device into routine clinical practice: the OdonAssist

Available evidence on OdonAssist, a novel assisted vaginal birth device, is limited to precommercial studies, and its performance during routine implementation by newly adopting teams remains unknown.

To assess the success rate of OdonAssist during early routine implementation and explore factors associated with success.

This multicenter retrospective observational study included all consecutive OdonAssist attempts in two French maternity units between July 2025 and May 2026. Success was defined as vaginal birth with OdonAssist alone. Factors associated with success, maternal and neonatal outcomes, and operator- and patient-reported experience were assessed.

Among 38 attempts by 8 obstetricians, 20 were successful (52.6%; 95% CI, 35.8-69.0). Success increased from 25.0% on each operator's first attempt to 52.4% for attempts 2-5 and 77.8% for attempts ≥6 (p for trend = 0.030). Slippage accounted for 14 failures (77.8%). All unsuccessful attempts were completed vaginally using another instrument. Maternal morbidity and clinically pertinent neonatal outcomes did not differ between groups. Operators were satisfied or very satisfied in 57.9% of assessments, and 76.7% of women with available data rated their overall childbirth experience as good or very good.

During initial implementation, the OdonAssist success rate increased with operator-specific experience. The learning curve should therefore be considered both during clinical implementation of the device and when interpreting findings from future studies.