Background & Method: The aim of present study is to study Role of cervical length in assessment of Preterm birth. Prematurity causes 70% of fetal/neonatal deaths, with 11.4% of births occurring at < 37 weeks gestation. The rate of prematurity increases with the number of fetuses - singletons 10%; twins 54.9%; and triplets 93.6%. The expansion of the bladder that is required with the transabdominal approach results in cervical lengthening and the translabial or transperineal technique do not give accurate measurement of cervical length. Therefore, the transvaginal approach is the most accurate method to assess the cervical length. Result: The incidence was 14% low birth weight; while in group B it was 17% and in group C it was 83%. Group A all delivered at term and no baby required NICU admission. Reduction in cervical length between 11-14 weeks to 20-22 weeks of gestation in prediction of preterm delivery. At the cut-off value of reduction in cervical length between 11-14 weeks and 20- 22 weeks of gestation of >0.6 cm, sensitivity was 66.67%, specificity was 87.5%, PPV was 42.11%, NPV was 95.06%, and p value was < 0.00001. Conclusion: Considering the magnitude of preterm labor, cost of management of preterm babies and morbidity-mortality associated with it, transvaginal ultrasonography of the cervix during routine NT scan and anomaly scan has emerged as a safe, acceptable and a costeffective test to assess risk of preterm delivery.