Cost-effectiveness of transabdominal ultrasound for cervical length screening for preterm birth prevention

OBJECTIVE: Transabdominal ultrasound (TAUS) cervical length (CL) screening has been proposed as an alternative to universal transvaginal screening to identify women at an increased risk of preterm birth. We sought to identify whether and under what circumstances TAUS would be cost-effective. STUDY DESIGN: This is a decision analytic model designed to compare an initial TAUS CL screening approach with universal transvaginal screening in a hypothetical cohort of women with a singleton pregnancy. Cost, probability, and utility estimates were derived from the existing literature. RESULTS: Under baseline assumptions, universal transvaginal was the dominant strategy. In comparison to TAUS, universal transvaginal CL screening reduced preterm birth by 0.03%, reduced costs by $1.2 million and increased quality-adjusted life years by 70 per 100,000 women. Although robust to many changes in many estimates, the model was sensitive to the cost of a transvaginal ultrasound, the prevalence of a short cervix and the test characteristics (ie, sensitivity and specificity) of a TAUS screening examination for short CL. CONCLUSION: Compared with an initial TAUS screen, universal transvaginal ultrasound was a more cost-effective strategy under most assumptions. Optimizing TAUS testing characteristics or applying a transabdominal screening strategy in lower risk populations may yield an initial TAUS to be cost-effective.