Prediction of preterm delivery in twins by cervical assessment at 23 weeks.
OBJECTIVE
To establish the relation between cervical length at 23 weeks of gestation in twin pregnancies and risk of spontaneous delivery before 33 weeks.


METHODS
Cervical length was measured by transvaginal sonography at 23 (range 22-24) weeks of gestation in 464 twin pregnancies attending for routine antenatal care. In the patients who were managed expectantly the relation between cervical length and the rate of spontaneous delivery before 33 weeks was determined.


RESULTS
The cervical length distribution was skewed to the left and the median value was 36 mm. The rate of spontaneous delivery before 33 weeks was inversely related to cervical length at 23 weeks. It increased gradually from about 2.5% at 60 mm, to 5% at 40 mm and 12% at 25 mm, and exponentially below this length to 17% at 20 mm and 80% at 8 mm. Cervical length of 20 mm or less is found in about 8% of the population and this group contained about 40% of women delivering spontaneously before 33 weeks.


CONCLUSIONS
In twin pregnancies measurement of cervical length provides useful prediction of risk for spontaneous early preterm delivery.
Harris Birthright Research Centre for Fetal Medicine, King's College Hospital Medical School, London, UK.
C
C
Skentou
A P
AP
Souka
M S
MS
To
A W
AW
Liao
K H
KH
Nicolaides
D000328:Adult; D002584:Cervix Uteri / Q000000981:diagnostic imaging*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007752:Obstetric Labor, Premature / Q000000981:diagnostic imaging* / Q000453:epidemiology; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology; D011272:Pregnancy, Multiple; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D014427:Twins; D016216:Ultrasonography, Prenatal