MEASUREMENT OF CERVICAL LENGTH BY VAGINAL SONOGRAPHY: PREDICTION OF PRETERM LABOR

Abstract

Introduction: Preterm delivery remains a major source of perinatal morbidity and mortality. The patient at risk for preterm delivery could be identified before the onset of uterine activity. Cervical shortening associates with increased risk of preterm delivery. Vaginal ultrasound for measurement of the cervical length can contribute to the prediction, diagnosis and management of preterm delivery.
Methods: 780 women attending the antenatal clinic of the Shahid Beheshti and Alzahra hospitals (January 1997 - February 1998) were selected. They had no complications. pregnant with gestational ages between 28-30 weeks were recruited in to the study. Cervical length was recorded by vaginal sonography. They followed up to delivery time.
Results: The mean cervical length of the term and preterm groups were statisticaly significantly different. The likelihood ratios of cervical length at various cutoff points were calculated. The appropriate cutoff point based on the receiver operating characteristic curve (35mm) was associated with a significant increased likelihood of preterm delivery.
Discussion: A single transvaginal sonographic measure of cervical length at 28-30 weeks gestational age can be used to predict the risk of preterm delivery using a cutoff point on 35mm.