PREDICTION OF PRE-TERM LABOUR BY ESTIMATING THE CERVICAL LENGTH AT MID GESTATION BY TVS

Abstract

Background: Preterm birth (PTB), defined as delivery before 37 weeks of gestation, remains a leading cause of neonatal morbidity and mortality worldwide. Accurate prediction is essential for early intervention and prevention. Transvaginal sonographic (TVS) measurement of cervical length (CL) during mid-gestation is a recognized method for assessing risk.

Objective: To evaluate the predictive value of mid-trimester cervical length measurement for spontaneous preterm birth (sPTB) using transvaginal sonography.

Methodology: A prospective observational study was conducted over six months, including 150 singleton pregnancies between 18–24 weeks of gestation. Cervical length was measured via TVS, and participants were categorized into two groups: CL ≤25 mm and CL >25 mm. All subjects were followed until delivery, and the incidence of sPTB (<37 weeks) was recorded. Diagnostic accuracy was assessed through sensitivity, specificity, predictive values, and ROC curve analysis.

Results: Of the 150 participants, 14.7% experienced sPTB. Women with CL ≤25 mm had a significantly higher rate of sPTB compared to those with CL >25 mm (58.3% vs. 7.1%, p < 0.001). The ≤25 mm cut-off demonstrated 60.9% sensitivity, 92.1% specificity, 58.3% positive predictive value, and 92.9% negative predictive value, with an overall accuracy of 87.3%. ROC analysis yielded an AUC of 0.84, confirming strong predictive performance.

Conclusion: Mid-trimester cervical length measurement via TVS is a reliable and non-invasive predictor of spontaneous preterm birth. A CL ≤25 mm significantly increases the risk of sPTB, while a normal CL provides strong reassurance of term delivery. Integration of universal CL screening into routine prenatal care may facilitate early risk stratification and reduce preterm birth rates through timely preventive interventions.