Risk of preterm delivery is increased if cervical length is lesser than:: (A) 2.5 cm., (B) 3.0 cm., (C) 3.5 cm., (D) 4.0 cm.
Answer is A. The chance of preterm labour increases more if in the second trimester the cervical length is lesser than 2.5 cms. The chances of effacing this cervix are rapid then with a smaller cervix.