Mid-trimester endovaginal sonography in women at high risk for spontaneous preterm birth.
Publication/Presentation Date
9-19-2001
Abstract
CONTEXT: Although shortened cervical length has been consistently associated with spontaneous preterm birth, it is not known when in gestation this risk factor becomes apparent.
OBJECTIVE: To determine whether sonographic cervical findings between 16 weeks' and 18 weeks 6 days' gestation predict spontaneous preterm birth and whether serial evaluations up to 23 weeks 6 days' gestation improve prediction in high-risk women.
DESIGN, SETTING, AND PARTICIPANTS: Blinded observational study performed between March 1997 and November 1999 at 9 university-affiliated medical centers in the United States in 183 women with singleton gestations who previously had experienced a spontaneous birth before 32 weeks' gestation.
OBSERVATION: Certified sonologists performed 590 endovaginal sonographic examinations at 2-week intervals. Cervical length was measured from the external os to the functional internal os along a closed endocervical canal. Funneling and dynamic cervical shortening were also recorded.
MAIN OUTCOME MEASURE: Spontaneous preterm birth before 35 weeks' gestation, analyzed by selected cutoff values of cervical length.
RESULTS: Forty-eight women (26%) experienced spontaneous preterm birth before 35 weeks' gestation. A cervical length of less than 25 mm at the initial sonographic examination was associated with a relative risk (RR) for spontaneous preterm birth of 3.3 (95% confidence interval [CI], 2.1-5.0; sensitivity = 19%; specificity = 98%; positive predictive value = 75%). After controlling for cervical length, neither funneling (P =.24) nor dynamic shortening (P =.054) were significant independent predictors of spontaneous preterm birth. However, using the shortest ever observed cervical length on serial evaluations, after any dynamic shortening, the RR of a cervical length of less than 25 mm for spontaneous preterm birth increased to 4.5 (95% CI, 2.7-7.6; sensitivity = 69%; specificity = 80%; positive predictive value = 55%). Compared with a single cervical measurement at 16 weeks' to 18 weeks 6 days' gestation, serial measurements at up to 23 weeks 6 days significantly improved the prediction of spontaneous preterm birth in a receiver operating characteristic curve analysis (P =.03).
CONCLUSIONS: Cervical length assessed by endovaginal sonography between 16 weeks' and 18 weeks 6 days' gestation, augmented by serial evaluations, predicts spontaneous preterm birth before 35 weeks' gestation in high-risk women.
Volume
286
Issue
11
First Page
1340
Last Page
1348
ISSN
0098-7484
Published In/Presented At
Owen, J., Yost, N., Berghella, V., Thom, E., Swain, M., Dildy, G. A., 3rd, Miodovnik, M., Langer, O., Sibai, B., McNellis, D., & National Institute of Child Health and Human Development, Maternal-Fetal Medicine Units Network (2001). Mid-trimester endovaginal sonography in women at high risk for spontaneous preterm birth. JAMA, 286(11), 1340–1348. https://doi.org/10.1001/jama.286.11.1340
Disciplines
Business Administration, Management, and Operations | Health and Medical Administration | Management Sciences and Quantitative Methods
PubMedID
11560539
Department(s)
Administration and Leadership
Document Type
Article