Ultrasound Assessment of Cervical Length in the First Trimester of Pregnancy to Predict Preterm Birth

Abstract

The aim of this study was to examine the potential value of routine measurement of cervical length (CL) in singleton pregnancy at 11 to 14 weeks of gestation for predicting the risk for spontaneous preterm delivery (PD). Materials and Methods: CL was assessed using transvaginal sonography (TVS) in the gestational period between 11 and 14 week in 1517 women. Childbirth at 22-36 weeks was considered as PD. The control group included pregnant women who gave birth within 37 weeks or more. Results: The mean age of mothers was 25.3±4.9 years (age range of 17 to 43). Among them, 846 (55.8%) women were primiparous and 671 (44.2%) - multiparous. The average CL was 38.9±4.3 mm (range of 18 to 49 mm). The area under the ROC curve of the corresponding relationship between the CL forecast and the probability of PD occurrence was 0.84. When selecting the threshold value of the function at the point 35 mm, we predicted a high risk of PD with a sensitivity of 66.2% and a specificity of 84.2%. At the CL value of 30 mm, the sensitivity of the method was 51.5%, specificity 98.7%. For CL: OR=0.79, 95% CI: 0.75-0.83; P=0.0001. Thus, the most optimal cut-off CL is the threshold value of 30mm. Conclusion: TVS is an objective, reproducible and reliable method for assessing the cervix uteri and can predict the risk of PD.

Keywords

• singleton pregnancy
• cervical length
• preterm delivery
• transvaginal sonography