Induction of Labor at 39 Weeks of Gestation Versus Expectant Management for Low-Risk Nulliparous Women: A Cost-Effectiveness Analysis

Inducing labor is commonly used to initiate labor before the spontaneous onset of labor for many indications. One of the major concerns about elective induction of labor (performed when there is no medical indication) is that it will increase risk of cesarean delivery. Previous studies that pointed to this this risk compared women undergoing induced labor with women in spontaneous labor when it is more appropriate to compare induced patients with those getting expectant management because expectant management leads to greater gestational age patients. A more recent study, the ARRIVE Trial, found that induction of labor at 39 weeks for low-risk nulliparous women was not associated with an increased risk of cesarean delivery or adverse neonatal outcomes. The researchers sought to determine the cost-effectiveness and health outcomes associated with induction of labor at 39 weeks versus expectant management for low-risk nulliparous women in the United States. The researchers performed an analysis using software with a theoretical cohort of 1.6 million women, approximately the number of nulliparous term births in the United States every year considered low risk. The model used compared outcomes in women induced at 39 weeks versus those expectantly managed. Primary outcomes included mode of delivery, hypertensive disorders of pregnancy, macrosomia, stillbirth, permanent brachial plexus injury, and neonatal death, as well as the cost and quality-adjusted life years (QALYs) for the woman and neonate. Probabilities used in the model originated from the literature, which set a cost-effectiveness threshold at $100,000 per QALY. In the hypothetical cohort of 1.6 million women, induction of labor resulted in 54,498 fewer cesarean deliveries and 79,152 fewer cases of hypertensive pregnancy disorders; it also resulted in 795 fewer stillbirths and 11 fewer neonatal deaths even though there were 86 more cases of brachial plexus injury. Cost-wise, induction of labor resulted in increased costs but also increased QALYs with a cost-effectiveness ratio of $87,691.91 per QALY. Sensitivity analysis determined that if labor induction cost $180 more, elective labor induction at 39 weeks would not be cost-effective; using probabilistic sensitive analysis, induction of labor was cost-effective 65% of the time. In conclusion, the researchers found that inducing labor in nulliparous women at 39 weeks had improved outcomes but increased costs in this simulation. The cost-effectiveness ratio was slightly cost-effective but would lead to approximately $2 billion in healthcare costs. The researchers acknowledge that this study was limited by the data input into the theoretical scenario: the numbers used were derived from lots of different studies. In addition, they also note that while these data can inform practice, it should not solely determine the best care for all individuals.