Changes in Rates of Hypertensive Disorders of Pregnancy Among Nulliparous Patients After the ARRIVE (A Randomized...

The ARRIVE (A Randomized Trial of Induction Versus Expectant Management) trial demonstrated lower rates of hypertensive disorders of pregnancy (HDP) among low-risk nulliparous patients undergoing labor induction at 39 weeks of gestation. We conducted a population-based cohort study in which we evaluated the association between the routinization of 39-week induction and the rate of HDP by comparing rates before and after the ARRIVE trial publication, using the National Vital Statistics System. Logistic regression models were used to project what the HDP rate would have been based on trends seen pre-ARRIVE. Despite an overall increase in the rate of HDP from pre-ARRIVE to post-ARRIVE (4.9% pre vs 6.3% post, adjusted odds ratio [aOR] 1.26, 95% CI 1.24-1.27), the HDP rate was significantly lower in the post-ARRIVE group among patients undergoing induction at 39 weeks of gestation (14.7% pre vs 14.1% post, aOR 0.91, 95% CI 0.90-0.93), decreasing by 12.0% per year (P<.001). The rate of HDP among all other delivering patients was higher in the post-ARRIVE group (4.1% pre vs 5.5% post, aOR1.32, 95% CI 1.30-1.34). Our findings may suggest that, as the overall HDP rate rises, the relative advantage of 39-week induction will rise similarly.