Sonographic measurement of cervical length in threatened preterm labor in singleton pregnancies with intact membranes.
OBJECTIVE
To predict when delivery will occur, within 48 h and 7 days of presentation and before 35 weeks' gestation in women presenting with threatened preterm labor.


METHODS
Sonographic measurement of cervical length was carried out in 510 women with singleton pregnancies presenting with threatened preterm labor and intact membranes at 24 to 33 + 6 weeks of gestation. The measurement was not taken into account in the subsequent management of the pregnancies. The outcome measures were delivery within 48 h and 7 days of presentation and delivery before 35 weeks.


RESULTS
The median gestation at presentation was 30 + 1 (range, 24 to 33 + 6) weeks and the median cervical length was 25 (range, 1-51) mm. Delivery within 48 h of presentation occurred in 21 (4.1%) cases, delivery within 7 days occurred in 43 (8.4%) and delivery before 35 weeks occurred in 76 (14.9%). Logistic regression analysis demonstrated that the only significant independent predictor of delivery within 48 h was cervical length (odds ratio (OR), 0.73; 95% CI, 0.65-0.81) and for delivery within 7 days the independent predictors were cervical length (OR, 0.69; 95% CI, 0.63-0.76) and vaginal bleeding (OR, 19.42; 95% CI, 3.87-97.4). In the subgroup of women who did not deliver within 7 days of presentation, the incidence of delivery before 35 weeks was 7.1% (33 of 467) and the only significant independent predictor of such delivery was cervical length (OR, 0.92; 95% CI, 0.88-0.96, P < 0.0001). There was no significant independent contribution to any of the outcome measures from ethnic group, maternal age, gestational age, body mass index, parity, cigarette smoking or use of tocolytics.


CONCLUSIONS
In women with threatened preterm labor sonographic measurement of cervical length helps to distinguish between true and false labor and to predict early preterm delivery.
Tsoi
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Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, Denmark Hill, London, UK.
Fuchs
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IB
Rane
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Geerts
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Nicolaides
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KH
D000293:Adolescent; D000328:Adult; D002584:Cervix Uteri / Q000000981:diagnostic imaging*; D036861:Delivery, Obstetric; D005321:Extraembryonic Membranes / Q000000981:diagnostic imaging*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007752:Obstetric Labor, Premature / Q000150:complications / Q000000981:diagnostic imaging*; D010298:Parity; D011247:Pregnancy; D011256:Pregnancy Outcome; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D012044:Regression Analysis; D012680:Sensitivity and Specificity; D013997:Time Factors; D014463:Ultrasonography; D014592:Uterine Hemorrhage / Q000150:complications / Q000000981:diagnostic imaging