title: [Cervical length in predicting preterm labor].
abstract: BACKGROUND
  Preterm birth is the birth occurring between 20-37 weeks gestation. Is responsible for 75% of neonatal mortality in infants without congenital malformations.
  
  
  OBJECTIVE
  To determine the prognostic factor of cervical length measurement in threatened preterm labor, in patients treated at a hospital in Veracruz, Mexico.
  
  
  METHODS
  Observational, prospective, longitudinal and descriptive study performed at the Obstetrics and Perinatology services of the Hospital General de Zona Núm. 71, IMSS, from May to December 2007.
  
  
  METHODS
  patients admitted to the obstetrics service with a diagnosis of preterm labor of 22 to 36 weeks, single gestation.
  
  
  METHODS
  history of premature rupture of membranes, uterine malformation, stillbirth, pregnancies of fetuses with birth defects, carriers of cerclage and a history of cervical cone biopsy. The cervicometry was performed with 7-9 MHz vaginal transducer; increased risk of preterm delivery were considered in patients with cervical length < 25 mm, the existence of funnel was also assessed. We determined the sensitivity, specificity, positive predictive value and negative.
  
  
  RESULTS
  We studied 73 pregnant women diagnosed with preterm labor. The average age was 26.5 + 5.2 years. Fourteen (19.2%) patients had a history of income for preterm labor in previous pregnancies. In ten patients (10.7%), measurement of cervical length < 25 mm and the criterion of the number of weeks of preterm delivery (22-36) agreed (true positives); and 58 (79.5%) patients with cervical length > 25 mm and > or = 38 weeks gestation also agreed (true negatives).
  
  
  CONCLUSIONS
  The sensitivity to correctly predict preterm delivery was 71%, specificity of 98%, positive predictive value of 91% and negative predictive value of 94%, so the cervicometry is considered a useful tool for treatment and monitoring of preterm delivery.
authors.affiliation: Hospital General de Zona Núm. 71 Benito Coquet Lagunes, Instituto Mexicano del Seguro Social, Veracruz, México.
authors.forename: Servando Germán
authors.initials: SG
authors.lastname: Serrano-Gómez
authors.forename: Martha Patricia
authors.initials: MP
authors.lastname: García-Morales
mesh_terms: D000886:Anthropometry; D002584:Cervix Uteri / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006801:Humans; D008800:Mexico / Q000453:epidemiology; D007752:Obstetric Labor, Premature / Q000175:diagnosis* / Q000473:pathology; D011237:Predictive Value of Tests; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology / Q000517:prevention & control; D011379:Prognosis; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014463:Ultrasonography