Labor
Poster Session 3
Taylor S. Freret, MD
Massachusetts General Hospital
Cambridge, MA, United States
Anjali J. Kaimal, MD (she/her/hers)
Professor and Vice Chair of Clinical Operations, Department of OBGYN
University of South Florida Morsani College of Medicine
Tampa, FL, United States
Alexander Melamed, MD, MPH
Massachusetts General Hospital
Boston, MA, United States
.jpg "Mark A. Clapp, MD, MPH (he/him/his) photo")
Mark A. Clapp, MD, MPH (he/him/his)
Massachusetts General Hospital
Boston, MA, United States
The ARRIVE trial showed that induction of labor at 39 weeks among low-risk nulliparous patients led to a lower rate of cesarean delivery. We sought to determine if the trial’s dissemination was associated with a change in the rate of induction of labor at 40 weeks and associated outcomes.
Study Design:
This was a repeated cross-sectional analysis using US natality data of patients who gave birth to cephalic, non-anomalous, non-small-for-gestational age infants between 40-43 completed weeks of gestation without hypertension or diabetes from Feb 2017-Aug 2019. A population-level interrupted time series (ITS) analysis was performed using Poisson regression. The period from Feb 2018-Aug 2018 was excluded from the analysis due to ongoing evidence dissemination. Level change and temporal trends in the rate of induction, induction at 40 weeks of gestation, cesarean delivery, and adverse neonatal outcome were compared before and after the dissemination period. Seasonality was accounted for with sine and cosine terms.
Results:
A total of 870,217 births were included (367,062 in the pre-period, 312,676 in the post-period). In the immediate post-period, the rate of induction increased from a predicted rate of 36.4%, had the trial not been disseminated, to 37.7% (IRR 1.04, 95% CI 1.00-1.07); the rate of induction at 40 weeks increased from 18.7% predicted to 20.2% (IRR 1.08, 95% CI 1.05-1.12) (Figure). The rate of cesarean delivery and adverse neonatal outcome did not change (cesarean delivery: 25.3% predicted vs 25.2% observed, IRR 1.00, 95% CI 0.96-1.03; adverse neonatal outcome: 5.3% predicted vs 5.0% observed, IRR 0.95, 95% CI 0.87-1.02). Changes in the trend of induction over time were also noted, with an additional 21 inductions/10,000 births at 40 weeks occurring per month (95% CI 2.8-40.0 inductions/10,000 births).
Conclusion:
Following the dissemination of the ARRIVE trial, induction of labor increased among low-risk patients at 40 weeks of gestation. However, there was no observed decrease in cesarean delivery, suggesting the benefits of induction of labor at 39 weeks may not extrapolate to this cohort.