[Uterine cervical length measurement by endovaginal ultrasonography: Technique and main utilizations].

Cervical length measurement by transvaginal ultrasound is commonly used to assess the risk of preterm birth (PTB) and refine the clinical management in cases of preterm labor (PTL). The transvaginal route is considered to be the reference for the measurement of the uterine cervix. Cervical length measurement has a good diagnostic value irrespective of the clinical context or past history associated with an increased risk of PTB. In case of PTL, the measurement of the cervical length by ultrasonography allows to reduce the number of hospitalizations, and to focus on the women who really need a treatment. In case of twin pregnancy, systematic systematic measurement of cervical length at 20-25 weeks gestation is not recommended because of the lack of therapeutic applications. In cases of high risk of PTB (PTB history, conization, uterine exposure to DES, etc.), selecting a group at high risk for PTB by a systematic cervical length measurement at 20-25 weeks gestation could be useful to select women for whom treatment with progesterone would be most beneficial. In this group, a follow-up of the cervical length since 16 weeks gestation may also be useful to indicate a cerclage if the cervical length is less than 15mm. In the general population, cervical length measurement may be useful during the second trimester of pregnancy in so far as a treatment by progesterone in cases of short cervix (<or=15mm) may be beneficial.