Identifying the effective components of a standardized labor induction protocol: secondary analysis of a randomized, controlled trial

Abstract

Objective Standardized labor induction protocols utilizing evidence-based active management practices are associated with improved obstetric outcomes. However, these protocols are complex and include multiple components. We aimed to identify which of the individual components of an evidence-based labor induction protocol are most associated with reduced rates of cesarean delivery, maternal morbidity, and neonatal morbidity. Study Design This is a secondary analysis of a randomized trial comparing time to delivery among four labor induction methods. All patients enrolled in the trial had their labor managed with a multidisciplinary-developed, evidence-based standardized labor induction protocol. For each patient’s induction, we assessed adherence to seven components of the protocol. Primary outcomes included cesarean delivery, maternal morbidity, and neonatal morbidity. Bivariate analyses assessed the association of each protocol component with each outcome. Multivariable logistic regression determined independent predictors of each outcome. Results The 491 patients enrolled in the randomized trial were included in this analysis. For cesarean delivery, while adherence to four of the seven protocol components was associated with the outcome in bivariate analyses, only adherence to “cervical exams should be performed every 1–2 h in active labor” was associated with reduced cesarean rates when controlling for age, body mass index, and parity. For maternal morbidity, while adherence to “if misoprostol is utilized, it should not be continued beyond 6 doses or 24 h of use” was associated in bivariate analysis, it was no longer associated with the outcome in multivariable analysis. Finally, “cervical exams should be performed every 1–2 h in active labor” and “cervical exams should be performed every 2–4 h in latent labor” were associated with reduced neonatal morbidity both in bivariate analyses as well as when controlling for age, body mass index, and parity. Conclusions Within a standardized labor induction protocol, adherence to cervical exams every 1–2 h in active labor was associated with reduced cesarean rate, and adherence to cervical exams every 2–4 h in latent labor, as well as every 1–2 h in active labor is associated with reduced neonatal morbidity. Regular cervical examination during labor induction likely allows for intervention when cervical change is not made. This data warrants further investigation into the optimal frequency of cervical exams during labor induction. Furthermore, an understanding of which components of a complex, evidence-based labor induction protocol are most effective may be helpful for streamlining and education around this protocol as implementation occurs across diverse sites.