To evaluate the effect of publication of the ARRIVE (A Randomized Trial of Induction Versus Expectant Management) trial on perinatal outcomes in singleton, term, nulliparous patients.
An interrupted time series analysis was performed using clinical data for nulliparous singleton births at 39 weeks of gestation or later at 13 hospitals in the Northwest region of the United States (January 2016–December 2020). A modified Poisson regression was used to model time trends and changes after the ARRIVE trial (August 9, 2018). Outcomes of interest were elective induction, unplanned cesarean births, hypertensive disorders of pregnancy, a composite of perinatal adverse outcomes, and neonatal intensive care unit admissions.
The analysis included 28,256 births (15,208 pre-ARRIVE and 13,048 post-ARRIVE). The rate of elective labor induction was 3.6% during the pre-ARRIVE period (January 2016–July 2018) and 10.8% post-ARRIVE (August 2018–December 2020). In the interrupted time series analysis, elective induction increased by 42% (relative risk [RR] 1.42; 95% CI 1.18–1.71) immediately after the ARRIVE trial publication. Thereafter, the trend was unchanged compared with the pre-ARRIVE period. There was no statistically significant change in cesarean birth (RR 0.96; 95% CI 0.89–1.04) or hypertensive disorders of pregnancy (RR 0.91; 95% CI 0.79–1.06) immediately after the trial, and no change in trend. After the ARRIVE trial, there was no immediate change in adverse perinatal outcomes, but a statistically significant increase in trend of adverse perinatal events (1.03; 95% CI 1.01–1.05) when compared with a declining trend observed in the pre-ARRIVE period.
Publication of the ARRIVE trial was associated with an increase in elective induction, and no change in cesarean birth or hypertensive disorders of pregnancy in singleton nulliparous patients giving birth at 39 weeks or later. There was a flattening of the pre-ARRIVE decreasing trend in perinatal adverse events.