[Cervical length in predicting preterm labor]

Preterm birth is the birth occurring between 20-37 weeks gestation. Is responsible for 75% of neonatal mortality in infants without congenital malformations.

To determine the prognostic factor of cervical length measurement in threatened preterm labor, in patients treated at a hospital in Veracruz, Mexico.

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.

patients admitted to the obstetrics service with a diagnosis of preterm labor of 22 to 36 weeks, single gestation.

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.

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).

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.