Predictive role of transvaginal ultrasonographic measurement of cervical length at 34 weeks for late pre-term and late-term deliveries in nulliparous women

Abstract

Objective: To investigate the predictive role of transvaginal ultrasonographic measurement of cervical length (CL) at 34 weeks of gestation in determining late-preterm and late-term deliveries in nulliparous women.Methods: CL was measured by transvaginal ultrasonography at 34 weeks in 318 women (singleton, nulliparous, low-risk and vertex presentation). All women were followed-up till birth and delivered at hospital. Deliveries were classifed according to gestational week as late-preterm (340/7 to 366/7 weeks), term (370/7 to 406/7 weeks) and late-term (410/7 to 416/7 weeks).Results: There was a significant correlation between CL at 34 weeks and gestational week at delivery (r = 0.614, p < 0.001). Receiver-operating characteristic curve analysis showed that CL measurement below 25.5 mm predicted late-preterm delivery with a sensitivity of 80.0%, specificity of 93.9%, positive predictive value (PPV) of 52.6% and negative predictive value (NPV) of 98.2%; while CL above 42.5 mm had 70.4% sensitivity, 93.5% specificity, 50.0% PPV and 97.1% NPV in prediction of late-term delivery.Conclusion: Measurement of CL with transvaginal ultrasonography at 34 weeks of gestation can be of beneficial in predicting the risk of late-preterm and late-term deliveries in nulliparous women.