Cervical assessment in women with threatened preterm labor

The aim of the study was to examine the clinical value of cervical assessment by transvaginal ultrasonography in women with symptoms of preterm labor.

We prospectively evaluated 172 women with singleton pregnancies and symptoms of preterm labor. Seventy of them were nulliparas, while 102 were multiparas. Gestational age ranged between 24 and 34 wks. All women underwent cervical assessment with transvaginal ultrasonography and were given intravenous tocolytics. The only parameter evaluated was cervical length. Women with multiple pregnancies, gestational age <24 wks or >34 wks, cervical dilatation >2 cm, placenta praevia, premature rupture of membranes, or cervical cerclage were excluded from the study. The outcome measure was delivery before 34 wks gestation.

The preterm delivery rate before 34 wks was 37%. The sensitivity and the specificity of a cervical length of less than 20 mm was 60 and 53.8% and 97.7 and 95.2% for nulliparas and multiparas, respectively. A cervical length <20 mm was also 93.7% predictive of preterm delivery in nulliparas and 87.5% in multiparas, while the corresponding numbers for its negative predictive value (NPV) were 81.4 and 76.9%, respectively.

Cervical assessment in women with symptoms of preterm labor can distinguish those at high risk for preterm delivery. Cervical sonography can be a valuable adjunct to the clinical evaluation of these patients.