Labor
Poster Session 2
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 decreased cesarean delivery rates. We sought to determine if the trial’s dissemination was associated with an increase in induction of labor among infants delivered at early term (37-38 completed weeks of gestation).
Study Design:
This repeated cross-sectional analysis used US natality data of 1,071,351 patients without hypertension or diabetes who gave birth to cephalic, non-SGA infants from January 2017-August 2019. A patient-level difference-in-differences (DID) analysis was performed using linear regression to determine if the ARRIVE trial was associated with changes in induction of labor among patients with early term deliveries compared to patients delivering at 36 weeks’ gestation, a cohort not expected to be influenced by the ARRIVE trial. A control group was used as inductions among “low-risk” patients before 39 weeks may be for medical indications that are not tracked on natality data. As a positive control, patients delivering at 39 weeks of gestation were also compared against the 36-week cohort.
Results:
Induction rates were increasing in each gestational age cohort before and after the trial’s publication (Figure). However, the trial did not increase inductions among infants born at 37 weeks of gestation (pre-period induction rate: 23.4%, post-period induction rate: 25.7%, adjusted DID estimate 0.2 percentage points (95% CI -0.6 to 1.0 pp, p=0.62) or 38 weeks of gestation (pre-period rate: 20.0%, post-period rate: 22.0%, adjusted DID estimate -0.2 pp (95% CI -0.9 to 0.6 pp, p=0.62) relative to the 36-week control group (pre-period rate: 22.0%, post-period rate 24.0%). As expected, the induction rate in the 39-week group did increase (pre-period rate: 26.6%, post-period rate: 31.0%, adjusted DID estimate 2.2 pp, 95% CI 1.4 to 2.9 pp, p< 0.001) compared to the control group (Table).
Conclusion:
Appropriately, publication of the ARRIVE trial and associated guidance did not result in an increase in early term induction of labor among patients without hypertension, diabetes, or SGA infants.