Predictive value of cervical length for spontaneous preterm birth in women with cervical cerclage

Post-cerclage CL is the predominant predictor of sPTB < 34 weeks' gestation. Underlying sPTB risk factors (previous cervical surgery and pregnancy history) may influence pre-cerclage CL and the direction of CL change following cerclage, but once these are adjusted for, they do not influence the risk of sPTB < 34 weeks' gestation. © 2025 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.