Clinical application

Sonographic measurement of cervical length is clinically useful in the prediction of PTB in the following situations:

• In asymptomatic women with previous history of PTB and in those with uterine abnormalities, such as unicornuate uterus, the cervical length should be measured every two weeks at between 14 and 24 weeks of gestation.
• In asymptomatic women with no previous history of PTB measurement of cervical length should be carried out routinely at the time of the second trimester scan at 20-24 weeks.