Induction of labor at 39 weeks of gestation versus expectant management for low-risk nulliparous women: a cost-effectiveness analysis.

BACKGROUND

A large, recent multicenter 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.

OBJECTIVE

We sought to examine the cost-effectiveness and outcomes associated with induction of labor at 39 weeks vs expectant management for low-risk nulliparous women in the United States.

STUDY DESIGN

A cost-effectiveness model using TreeAge software was designed to compare outcomes in women who were induced at 39 weeks vs expectantly managed. We used a theoretical cohort of 1.6 million women, the approximate number of nulliparous term births in the United States annually that are considered low risk. Outcomes included mode of delivery, hypertensive disorders of pregnancy, macrosomia, stillbirth, permanent brachial plexus injury, and neonatal death, in addition to cost and quality-adjusted life years for both the woman and neonate. Model inputs were derived from the literature, and a cost-effectiveness threshold was set at $100,000/quality-adjusted life years.

RESULTS

In our theoretical cohort of 1.6 million women, induction of labor resulted in 54,498 fewer cesarean deliveries and 79,152 fewer cases of hypertensive disorders of pregnancy. We also found that induction of labor resulted in 795 fewer cases of stillbirth and 11 fewer neonatal deaths, despite 86 additional cases of brachial plexus injury. Induction of labor resulted in increased costs but increased quality-adjusted life years with an incremental cost-effectiveness ratio of $87,691.91 per quality-adjusted life year. In sensitivity analysis, if the cost of induction of labor was increased by $180, elective induction would no longer be cost effective. Similarly, we found that if the rate of cesarean delivery was the same in both strategies, elective induction of labor at 39 weeks would not be a cost-effective strategy. In probabilistic sensitivity analysis via Monte Carlo simulation, we found that induction of labor was cost effective only 65% of the time.

CONCLUSION

In our theoretical cohort, induction of labor in nulliparous term women at 39 weeks of gestation resulted in improved outcomes but increased costs. The incremental cost-effectiveness ratio was marginally cost effective but would lead to an additional 2 billion dollars of healthcare costs. Whether individual clinicians and healthcare systems offer routine induction of labor at 39 weeks will need to depend on local capacity, careful evaluation and allocation of healthcare resources, and patient preferences. KEY WORDS: cesarean delivery, decision analysis, healthcare resources, induction of labor, low-risk nulliparous women, mode of delivery, obstetric outcomes.