Gynaecology & Obstetrics Preterm Labour & Interauterine Fetal Death 6d248217 Cut off value of cervical length for prediction of preterm labor? A 1.5 cm B 2.5 cm C 3.5 cm D 4.5 cm High-Yield Explanation Ans- B. To diagnose preterm Labour cervical length must be less than 2.5 cm .