title: Universal cervical-length screening to prevent preterm birth: a cost-effectiveness analysis.
abstract: 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%.
  
  
  CONCLUSIONS
  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).
authors.affiliation: Department of Obstetrics, Gynecology & Reproductive Sciences, Section of Maternal Fetal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA. erika.werner@yale.edu
authors.forename: E F
authors.initials: EF
authors.lastname: Werner
authors.forename: C S
authors.initials: CS
authors.lastname: Han
authors.forename: C M
authors.initials: CM
authors.lastname: Pettker
authors.forename: C S
authors.initials: CS
authors.lastname: Buhimschi
authors.forename: J A
authors.initials: JA
authors.lastname: Copel
authors.forename: E F
authors.initials: EF
authors.lastname: Funai
authors.forename: S F
authors.initials: SF
authors.lastname: Thung
mesh_terms: D054791:Cervical Length Measurement / Q000379:methods*; D002584:Cervix Uteri / Q000002:abnormalities / Q000000981:diagnostic imaging*; D003362:Cost-Benefit Analysis; D003663:Decision Trees; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008403:Mass Screening / Q000379:methods; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D047928:Premature Birth / Q000000981:diagnostic imaging* / Q000191:economics / Q000517:prevention & control; D014481:United States