Cervical length and dilatation of the internal cervical os detected by vaginal ultrasonography as markers for preterm delivery: A systematic review.
OBJECTIVE
We performed a systematic review to evaluate endovaginal cervical ultrasonography as a predictor of preterm delivery.


METHODS
Selection criteria were original published English-language reports of prospective studies including women at <37 weeks' gestation with intact amniotic membranes. Parameters and outcomes were cervical length or dilatation of the internal cervical os and preterm delivery.


RESULTS
In 3 subgroups of studies including patients with preterm labor or low-risk, symptom-free patients with early (20-24 weeks) or late (27-32 weeks) ultrasonographic examination, optimal cutoff values for cervical lengths ranged between 18 and 30, 25 and 35, or 25 and 39 mm. At these cutoff values, sensitivity rates were between 68% and 100%, 33% and 54%, or 63% and 76%, and specificity rates were between 44% and 79%, 73% and 91%, or 59% and 69%, respectively. Sensitivity rates for dilatation of the internal cervical os were 70% to 100%, 16% to 25%, or 33%, and specificity rates were 54% to 75%, 95% to 99%, or 92%, respectively.


CONCLUSIONS
In patients with symptoms of preterm labor, endovaginal cervical ultrasonography appears to be an effective predictor of preterm delivery.
Leitich
H
H
Department of Obstetrics and Gynecology, University of Vienna, Austria.
Brunbauer
M
M
Kaider
A
A
Egarter
C
C
Husslein
P
P
D002584:Cervix Uteri / Q000000981:diagnostic imaging* / Q000502:physiology*; D005260:Female; D006801:Humans; D007752:Obstetric Labor, Premature / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal / Q000592:standards*