Role of mid-trimester transvaginal cervical ultrasound in prediction of preterm delivery.

The objective of this study was Transvaginal Ultrasonography (TVS) to examine the potential of routine measurement of cervical parameters by TVS at mid-trimester to predict preterm delivery. Cervical parameters measured by TVS at 20-24 weeks were critically analyzed for their ability to predict spontaneous preterm birth. The risk of spontaneous preterm delivery increased steeply as cervical length decreased. At a cut off value of d<2.5 cm, the cervical length measurements had sensitivity, specificity, positive predictive value and negative predictive value of 77%, 95%, 56% and 98% respectively. Our data suggests that the duration of pregnancy is directly related to length of the cervix, the shorter the cervix, the greater the chance of preterm delivery.