Cervical assessment.

Transvaginal scan (TVS) of cervical length (CxL) at mid-trimester anomaly scan in asymptomatic pregnancy is useful for predicting the risk of preterm birth. In symptomatic women, measurement of CxL at presentation can help to distinguish between true and false preterm labor (PTL), and who might not deliver within 48 h and seven days. In both groups, the individualization of risk would lead to improvement of antenatal care, including frequency of visits, patient education to identify earlier symptoms, avoid excessive hospitalization, and unnecessary steroids. It is also possible that vaginal progesterone and/or cerclage reduce the PTB risk on those asymptomatic women with short cervix. The aim is to review the evidence that supports the use of TVS of CxL in both asymptomatic and symptomatic pregnant women for the prediction and management of PTL.