1. Cervical length measured by transvaginal ultrasound can predict preterm birth, with a length under 25mm indicating higher risk. 2. For women at high risk of preterm birth due to prior preterm births or cervical procedures, regular cervical length screenings from 16-24 weeks and interventions for those under 25mm can help prevent preterm birth. 3. Cervical length is also a useful predictor for twin and triplet pregnancies, though the accuracy varies more than for single pregnancies. Interventions like cerclage or progesterone may help for women with short cervical lengths.