Objective: To establish the prognostic usefulness of cervical length and uterine artery pulsatility index for imminent preterm delivery in symptomatic patients. Design: Case-control study. Setting: Central Hospital "Dr. Urquinaona ", Maracaibo, Venezuela. Participants: Patients with preterm delivery within 7 days (group A) and pregnant women with preterm delivery within more than 7 days (group B). Methods: Cervical length and uterine artery pulsatility index were determined at hospital admission and all were followed until delivery. Main outcome measures: General characteristics, cervical length, uterine artery pulsatility index, imminent preterm delivery, and prognostic efficacy. Results: 119 participants were assigned to group A and 362 patients to group B. Cervical length was lower in group A, and the uterine artery pulsatility index was higher compared with group B (p <0.0001). Cervi...