ARRIVE trial linked to increased labor induction rates, reduced cesarean births

Key takeaways:

• Researchers saw an increase in 39-week labor induction rates after the ARRIVE trial was published in 2018.
• Cesarean delivery rates were significantly lower vs. expected rates based on pre-ARRIVE trial trends.

Publication of the ARRIVE trial was linked to a rise in 39-week labor induction rates and a decrease in cesarean birth rates among low-risk nulliparous women, according to a research letter published in JAMA Network Open.

The ARRIVE trial was a randomized trial published in August 2018 that evaluated labor induction vs. expectant management in births. ARRIVE demonstrated that, compared with expectant management among low-risk nulliparous women, elective labor induction at 39 weeks gestation led to a 16% decrease in the risk for cesarean birth and a 36% decrease in the risk for hypertensive disorders of pregnancy. These results led to a change in U.S. obstetrics guidelines to indicate that early 39-week inductions were reasonable for first time, low-risk pregnant women.

“Our objective was to evaluate if the publication of this trial was associated with observable obstetric practice changes in the U.S.,” Rachel Wood, MD, from the division of maternal-fetal medicine in the department of obstetrics and gynecology at Brigham and Women’s Hospital, and colleagues wrote. “We hypothesized the rate of 39-week induction would increase and cesarean delivery would decrease for low-risk nulliparous patients after publication and dissemination of the ARRIVE trial.”

As Healio previously reported, publication of the ARRIVE trial was associated with an increase in the likelihood of elective labor induction, according to a separate analysis published in Obstetrics & Gynecology that evaluated 28,256 singleton, nulliparous births at 39 weeks gestation or later. That analysis found that the rates of elective or medically indicated labor induction (34.7% before vs. 43% after) and elective labor induction (3.6% before vs. 10.8% after) were higher after publication of the ARRIVE trial.

Wood and colleagues conducted a population-level interrupted time series analysis of 2,860,942 births from low-risk nulliparous women who delivered at 39 weeks gestation or later from January 2016 to March 2020. Births from the pre-ARRIVE period (January 2016 to July 2018) were compared with births after publication of the ARRIVE trial (November 2018 to March 2020). The primary exposure was the publication of the ARRIVE trial in August 2018 and a 3-month dissemination period.

Overall, 66% of births occurred before publication of the ARRIVE trial and 34% occurred after publication. Researchers noted an immediate increase in 39-week labor induction rates after the dissemination period compared with expected rates based on trends before the publication (15% vs. 13.8%; adjusted incident rate ratio [IRR] = 1.1; 95% CI, 1.08-1.13; P < .001). In addition, cesarean delivery rates were significantly lower compared with expected rates based on trends before publication of the ARRIVE trial (24.7% vs. 25.1%; aIRR = 0.988; 95% CI, 0.978-0.997; P = .01).

Researchers also observed significant ongoing temporal changes, with an increase of 0.009 39-week inductions per month, and a decrease of 0.0014 cesarean deliveries per month (P < .001 for both).

“Future work is needed to understand whether the findings of the ARRIVE trial are being implemented similarly in different subgroups and if trends are similar in all practice settings,” the researchers wrote.

References:

• Grobman WA, et al. N Engl J Med. 2018;doi:10.1056/NEJMoa1800566.
• Nethery E, et al. Obstet Gynecol. 2023;doi:10.1097/AOG.0000000000005217.