Against Recommending History Indicated Cerclage.

Cerclage was originally devised by Shirodkar and McDonald for individuals who develop cervical changes in the second trimester. RCT data have confirmed the efficacy of ultrasound-indicated cerclage (UIC). After 70 years of research, the only evidence-based indications for history-indicated cerclage (HIC) are ≥3 early spontaneous preterm births (SPTBs) or early second-trimester losses, and UIC followed by preterm birth <32 weeks. All patients should undergo transvaginal ultrasound cervical length (TVU CL) screening, with UIC considered if the TVU CL shortens before 24 weeks to ≤20 mm in singletons without prior SPTB, ≤25 mm with prior SPTB, or ≤15 mm in twins.