RESUMEN
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.