Cost-effectiveness of induction of labor at 39 weeks vs expectant management by cervical examination

Background

Previous analyses have demonstrated the cost effectiveness of elective induction of labor at 39 weeks of gestation for healthy nulliparous people. However, elective induction of labor is resource intensive, and optimal resource allocation requires a thorough understanding of which subgroups of patients will benefit most.

Objective

This study aimed to determine whether induction of labor at 39 weeks of gestation is more cost-effective in patients with favorable or unfavorable cervical examinations.

Study Design

We constructed 2 decision analysis models using TreeAge software: one modeling induction of labor at 39 weeks of gestation vs expectant management for a group of nulliparous patients with unfavorable cervical examinations and the other modeling induction of labor at 39 weeks of gestation vs expectant management for a group with favorable cervical examinations. Estimates of cost, probability, and health state utility were derived from the literature. Based on previous literature, we assumed that people with favorable cervical examinations would have a lower baseline rate of cesarean delivery and higher rates of spontaneous labor.

Results

In our base case analysis, induction of labor at 39 weeks of gestation was cost-effective for patients with unfavorable cervical examinations, but not for patients with favorable cervical examinations. The incremental cost per quality-adjusted life year was 50-fold lower for people with unfavorable cervical examinations ($2150 vs $115,100). Induction of labor resulted in 3885 fewer cesarean deliveries and 58 fewer stillbirths per 100,000 patients for those with unfavorable examinations, whereas induction of labor resulted in 2293 fewer cesarean deliveries and 48 fewer stillbirths with labor induction for those with favorable cervical examinations. The results were sensitive to multiple inputs, including the likelihood of cesarean delivery, the cost of induction, the cost of vaginal or cesarean delivery, and the probability of spontaneous labor. In Monte Carlo analysis, the base case findings held true for 64.1% of modeled scenarios for patients with unfavorable cervixes and 55.4% of modeled scenarios for patients with favorable cervixes.

Conclusion

With a willingness-to-pay threshold of $100,000 per quality-adjusted life year, induction of labor at 39 weeks of gestation may be cost-effective for patients with unfavorable cervical examinations, but not for patients with favorable cervical examinations. This result was driven by the likelihood of labor in patients with favorable cervical examinations, and the resultant avoidance of prolonged pregnancy and its complications, including hypertensive disorders of pregnancy and stillbirths. Health systems may wish to prioritize patients with unfavorable cervical examinations for elective induction of labor at 39 weeks of gestation, which may be opposite to common practice.