Impact of a Simulation-Based Training Program on Cup Detachment During Vacuum-Assisted Vaginal Birth: Protocol for a...

Safe vacuum-assisted vaginal birth depends on appropriate case selection, accurate cup placement, controlled traction, recognition of technical difficulty, and timely abandonment of an unsuccessful attempt. Simulation-based education can improve procedural performance, but evidence that vacuum-specific simulation changes patient-level clinical practice remains limited.

This study aims to estimate the change in the occurrence of cup detachment (known as "pop off") following implementation of a standardized simulation-based training program for vacuum-assisted vaginal birth. Cup detachment was designated as the single primary outcome after evaluation of the preintervention cohort but before any postintervention versus preintervention comparative analysis.

This multicenter quasi-experimental before-and-after study is being conducted in 19 Spanish maternity hospitals participating in the Registro Español de Morbimortalidad Materna y Perinatal. The implemented preintervention observation period ran from November 28, 2024, through February 28, 2026. The training and washout phase was conducted during March and April 2026, followed by postintervention data collection from May through October 2026. Preintervention clinical variables are ascertained retrospectively from medical records, whereas postintervention data collection is prospective. The intervention combines preparatory theoretical material, a 1-hour face-to-face simulation workshop using a PROMPT FLEX obstetric simulator and vacuum devices, checklist-based assessment, supervised practice, feedback, and debriefing. The primary outcome will be analyzed using modified Poisson regression to estimate risk ratios and 95% CIs, accounting for hospital and protocol-defined calendar time trends. Sequential instrumentation and conversion to cesarean birth will be analyzed separately as key secondary clinical outcomes. Ethical approval was granted by the Clinical Research Ethics Committee of Girona (code 2024.070) on August 5, 2024.

This study was funded in November 2024. During the preintervention phase, 1155 cases were recorded in 19 hospitals; 12 were excluded according to the selection criteria, leaving 1143 eligible cases. At the verified July 2026 project update, 144 postintervention cases had been collected. Postintervention data collection is scheduled to close in October 2026; the protocol-defined comparative analysis will be performed after database lock, with publication of the main results planned for summer 2027.

The current analysis plan was fixed before database lock and before any formal comparative postintervention versus preintervention effectiveness analysis. The protocol also defines assessment of contamination, intervention fidelity, secular trends, and the limitations inherent to a nonrandomized before-and-after evaluation.