Universal cervical‐length screening to prevent preterm birth: a cost‐effectiveness analysis

Objective To determine whether routine measurement of second‐trimester transvaginal cervical length by ultrasound in low‐risk singleton pregnancies is a cost‐effective strategy. Methods We developed a decision analysis model to compare the cost‐effectiveness of two strategies for identifying pregnancies at risk for preterm birth: (1) no routine cervical length screening and (2) a single routine transvaginal cervical length measurement at 18–24 weeks' gestation. In our model, women identified as being at increased risk (cervical length < 1.5 cm) for preterm birth would be offered daily vaginal progesterone supplementation. We assumed that vaginal progesterone reduces preterm birth at < 34 weeks' gestation by 45%. We also assumed that a decreased cervical length could result in additional costs (ultrasound scans, inpatient admission) without significantly improved neonatal outcomes. The main outcome measure was incremental cost‐effectiveness ratio. Results Our model predicts that routine cervical‐length screening is a dominant strategy when compared to routine care. For every 100 000 women screened, $ 12 119 947 can be potentially saved (in 2010 US dollars) and 423.9 quality‐adjusted life‐years could be gained. Additionally, we estimate that 22 cases of neonatal death or long‐term neurologic deficits could be prevented per 100 000 women screened. Screening remained cost‐effective but was no longer the dominant strategy when cervical‐length ultrasound measurement costs exceeded $ 187 or when vaginal progesterone reduced delivery risk at < 34 weeks by less than 20%. Conclusion In low‐risk pregnancies, universal transvaginal cervical length ultrasound screening appears to be a cost‐effective strategy under a wide range of clinical circumstances (varied preterm birth rates, predictive values of a shortened cervix and costs). Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.