<prompt> Cut off value of length of cervix at 24 weeks of gestation for prediction of preterm delivery is0.5 cm1.5 cm2.5 cm3.5 cm  <response>: Diagnosis of preterm labor : Regular uterine contractions with or without pain Dilatation more than 2cm and 80 effacement of cervix Length of the cervix 2.5 cm and funnelling of internal os Pelvic pressure, backache ,vaginal discharge Ref: Dutta Obs 9e pg 294. 