This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Preterm Labour & Interauterine Fetal Death, Subject name: Gynaecology & Obstetrics
Cut off value of cervical length for prediction of preterm labor? 
Select and explain. 
A. 1.5 cm, B. 2.5 cm, C. 3.5 cm, D. 4.5 cm
B: 2.5 cm
Answer: B: 2.5 cm 
Explanation: Ans- B. To diagnose preterm Labour cervical length must be less than 2.5 cm .