The ARRIVE trial: Women’s desideratum versus logistical concerns
Do findings from the ARRIVE study and subsequent outcomes and cost analyses require a full reconsideration of long-held obstetric practices?
Is induction of labor at 39 weeks cost-effective?
Hersh and colleagues performed a cost-effectiveness analysis for induction of labor at 39 weeks versus expectant management for low-risk nulliparous women.7 Based on 2016 National Vital Statistics Data, there were 3.5 million term births in the United States. Following the exclusion of high-risk pregnancies and term parous low-risk pregnancies, a theoretical cohort of 1.6 million low-risk nulliparous women was included in the analysis. A decision-tree analytic model was created, in which the initial node stratified low-risk nulliparous women into 2 categories: elective induction at 39 weeks and expectant management. Probabilities of maternal and neonatal outcomes were derived from the literature.
Maternal outcomes included hypertensive disorders of pregnancy and delivery mode. Neonatal outcomes included macrosomia, shoulder dystocia, brachial plexus injury, stillbirth, and neonatal death. Costs of clinic and triage visits, induction of labor, modes of delivery, and maternal and neonatal outcomes were derived from previous studies and adjusted for inflation to 2018 dollars. Finally, quality-adjusted life years (QALYs) were calculated for mothers and neonates and were then used to estimate the incremental cost-effectiveness ratio (ICER) of elective induction of labor at 39 weeks. Following accepted standards, the threshold for cost-effectiveness was set at $100,000/QALYs or less.
Induction at 39 weeks comes in lower cost-wise than the standard threshold for QALY. In their analysis, the investigators found that if all 1.6 million women in their theoretical cohort underwent an elective induction of labor at 39 weeks (rather than expectant management), there would be 54,498 fewer CDs, 79,152 fewer cases of hypertensive disorders, 795 fewer cases of stillbirth, and 11 fewer neonatal deaths. Due to the decreased CD rates, the investigators did project an estimated 86 additional cases of neonatal brachial plexus injury. Using these estimates, costs, and utilities, the authors demonstrated that, compared with expectant management, elective induction of labor at 39 weeks was marginally cost-effective with an ICER of $87,692 per QALY, which was lower than the cost-effectiveness threshold of $100,000 per QALY.
Based on additional sensitivity analyses, the authors concluded that cost-effectiveness of elective induction of labor varied based on variations in model inputs. Specifically, the authors demonstrated that cost-effectiveness of induction of labor varied based on labor induction techniques, modes of delivery, and fluctuations in the rates of CD in induction versus expectant management groups.
Despite these theoretically imputed findings, the authors acknowledged the limitations of their study. Their cost-effectiveness model did not account for costs associated with long-term health impact of CD and hypertensive disease of pregnancy. Additionally, their model did not account for an increase in cost and resource utilization associated with increased time on L&D units to accommodate women undergoing induction. Furthermore, the analysis did not take into account the bundled payments for vaginal versus CDs, which are increasing in prevalence. Lastly, the analysis did not consider the incremental increase in severe neonatal and maternal morbidity from 39 to 41 weeks that Chen et al found in their study.5
Will ARRIVE finally arrive?
Cognizant of the medical and economic benefits of 39-week inductions, the Society for Maternal-Fetal Medicine and the American College of Obstetrics and Gynecology published a joint practice advisory recommending “shared decision-making” when counseling low-risk women about induction.8 While more research is needed to validate the aforementioned findings, particularly in regard to resource utilization, the ARRIVE trial and its associated analyses suggest that a reconsideration to deliver term low-risk nulliparous women at 39 weeks is warranted.
In summary, the overwhelming evidence suggests that, among low-risk nulliparous women there are maternal and neonatal benefits with delivery at 39 weeks, as compared with expectant management. Logistical concerns should not interfere with women’s desideratum for optimal outcomes.
