Prediction of Preterm Delivery With Serial Cervical Length Measurements After Threatened Preterm Labor

Prospective cohort study on pregnant women discharged from the hospital after the first episode of threatened preterm labor. Cervical length (CL) will be measured with transvaginal US upon initial presentation (i.e at the time of hospital admission), at the time of hospital discharge, and respectively 2, 4, 8 and 12 weeks later. Pregnant women undelivered after the 1st episode of threatened preterm labor will be invited to participate in the study if CL upon discharge is \< 25 mm. The study will investigate the potential association between cervical shortening over time and time of delivery, to assess if spontaneous preterm delivery can be predicted by CL.