Objective: The aim of this study was to assess the role of cervical ultrasonography in the prediction of spontaneous preterm birth in triplet gestations and to compare various ultrasonographic cervical parameters with respect to predictive ability.
Study design: This prospective cohort study included 51 triplet gestations longitudinally evaluated between 15 and 28 weeks' gestation on 274 occasions with transvaginal cervical ultrasonography and transfundal pressure. The cervical parameters obtained were funnel width and length, cervical length, percentage of funneling, and cervical index.
Results: Receiver operating characteristic curve analyses showed that cervical lengths of < or =2.5 cm and < or =2.0 cm between 15 and 24 weeks' gestation and between 25 and 28 weeks' gestation, respectively, were at least as good as other ultrasonographic cervical parameters for the prediction of spontaneous preterm birth. A cervical length of < or =2.5 cm between 15 and 20 weeks' gestation had both a specificity and a positive predictive value of 100% for delivery at <28 weeks' gestation, and the sensitivities and negative predictive values ranged from 25% to 50% and from 72% to 91%, respectively, for deliveries at <28, <30, and <32 weeks' gestation. A cervical length of < or =2.5 cm between 21 and 24 weeks' gestation had an 86% sensitivity for prediction of spontaneous delivery at <28 weeks' gestation. A cervical length of < or =2.0 cm between 25 and 28 weeks' gestation had both a sensitivity and a negative predictive value of 100% for delivery at both <28 and <30 weeks' gestation.
Conclusions: In triplet gestations cervical lengths of < or =2.5 cm between 15 and 24 weeks' gestation and < or =2.0 cm between 25 and 28 weeks' gestation were at least as good as other ultrasonographic cervical parameters for the prediction of spontaneous preterm birth.