The impact of implementing a standardized protocol for labor induction on obstetric disparities: secondary analysis of a type I hybrid effectiveness-implementation trial

Abstract

Introduction: Prior retrospective data demonstrated that standardization of labor induction may reduce racial disparities in cesarean delivery and morbidity. Here, we aimed to determine the impact of prospectively implementing an induction protocol on racially disparate outcomes.

Methods: This was a planned secondary analysis of a type I hybrid effectiveness-implementation trial comparing 2 years before (PRE) and 2 years after (POST) implementation of a standardized induction protocol at two labor units (2018 to 2022). The protocol had eight components and recommended active induction management, frequent cervical exams, and amniotomy by first exam ≥4 cm. All singleton pregnancies ≥37 weeks with intact membranes requiring cervical ripening were eligible; prior cesarean delivery was excluded. Data were collected via individual chart review. This analysis included only those with self-identified race, divided into Black, Indigenous, People of Color (BIPOC), and white. Poisson regression with interaction terms evaluated the protocol’s impact on disparities in cesarean delivery and morbidity. Fidelity to the protocol was defined as adherence to ≥75% of the eight protocol components.

Results: A total of 8386 patients were included (PRE = 4167; POST = 4219); 59.3% were identified as BIPOC. BIPOC patients differed in delivery site, insurance, body mass index, parity, age, diagnosis of diabetes and hypertension, gestational age, and induction indication. BIPOC patients were more likely to undergo cesarean in the PRE (aRR 1.36[1.18–1.58]) period, and remained more likely to undergo cesarean POST-implementation (aRR 1.55[1.33–1.70]), even when controlling for differences between groups. Similarly, maternal morbidity was greater among BIPOC patients PRE-implementation (aRR 1.25[1.07–1.46]) and remained greater among BIPOC patients POST-implementation (aRR 1.34[1.14–1.58]). There was no difference by race/ethnic group in neonatal morbidity in either PRE or POST. Finally, the protocol was implemented similarly by BIPOC versus white.

Conclusion: Despite uniform implementation of a standardized induction protocol across race/ethnic groups, this intervention did not mitigate observed racial disparities in cesarean or maternal morbidity.

Nicholas J. Seewald

Assistant Professor of Biostatistics

Assistant Professor of Biostatistics at the University of Pennsyvlania Perelman School of Medicine