Medical/Surgical/Diseases/Complications
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 (IOL) at 39 weeks among low-risk nulliparous patients led to decreased cesarean delivery (CD) rates, with similar results in a subgroup analysis that stratified by obesity (BMI≥30) at randomization (38 weeks). We sought to determine if the trial was associated with changes in IOL, CD, or neonatal outcome among patients with pre-pregnancy obesity.
Study Design:
This repeated cross-sectional analysis used US natality data of nulliparous patients with a pre-pregnancy BMI ≥30 kg/m2 who gave birth to cephalic, non-SGA infants between 39 and 43 completed weeks of gestation from Feb 2017-Aug 2019. Patients with hypertension or diabetes were excluded. A population-level interrupted time series analysis was performed using Poisson regression. The primary outcome was 39-week IOL. Secondary outcomes included CD and a composite neonatal outcome (perinatal death, respiratory support, seizures, antibiotic treatment, or 5-min Apgar ≤3). Feb to Aug 2018 was excluded from the analysis as a time of active trial dissemination. The pre-period occurred from Feb 2017 to Jan 2018; the post-period from Sep 2018 to Aug 2019.
Results:
The study included 286,576 patients; 111,502 in the pre-period, 63,690 in the dissemination period, and 111,384 in the post-period. In the first month after the dissemination, the rate of 39-week IOL increased from 12.2% (expected) to 13.9% (incidence rate ratio 1.14, 95% CI 1.07-1.22, p< 0.001). The monthly rate of change also increased (IRR 1.02, 95% CI 1.01-1.03, p=0.001). However, CD also increased, from 33.1% expected to 35.0% observed, (IRR 1.06, 95% CI 1.01-1.11, p=0.03). There was no significant difference in the rate of change of CD over time or in composite adverse neonatal outcome (Figure).
Conclusion:
Dissemination of the ARRIVE trial resulted in a 14% increase in the rate of 39-week IOL among low-risk patients with pre-pregnancy obesity. However, this was associated with a 6% increase in cesarean delivery, suggesting that the reduction in cesarean anticipated with elective induction may not be observed in this group.