Transvaginal sonographic cervical length for the prediction of spontaneous preterm birth in twin pregnancies: a systematic review and metaanalysis

Abstract

Objective: To assess the accuracy of transvaginal sonographic cervical length (CL) in predicting spontaneous preterm birth in women with twin pregnancies.

Study design: Systematic review and metaanalysis of predictive test accuracy.

Results: Twenty-one studies (16 in asymptomatic women and 5 in symptomatic women) with a total of 3523 women met the inclusion criteria. Among asymptomatic women, a CL <or=20 mm at 20-24 weeks' gestation was the most accurate in predicting preterm birth <32 and <34 weeks' gestation (pooled sensitivities, specificities, and positive and negative likelihood ratios of 39% and 29%, 96% and 97%, 10.1 and 9.0, and 0.64 and 0.74, respectively). A CL <or=25 mm at 20-24 weeks' gestation had a pooled positive likelihood ratio of 9.6 to predict preterm birth <28 weeks' gestation. The predictive accuracy of CL for preterm birth was low in symptomatic women.

Conclusion: Transvaginal sonographic CL at 20-24 weeks' gestation is a good predictor of spontaneous preterm birth in asymptomatic women with twin pregnancies.

Figure 1

Study selection process

Figure 2

Methodological quality of studies included in the systematic review. Data presented as percentages across all included studies. Figures in the stacks represent number of studies.

Figure 3

Summary receiver operating characteristic (ROC) curves of cervical length tested at 20-24 weeks of gestation in asymptomatic women to predict spontaneous preterm birth: A) <28; B) <32; C) <34; D) <37 weeks of gestation. The area of each circle, rectangle and diamond is proportional to study’s sample size.

Figure 3

Summary receiver operating characteristic (ROC) curves of cervical length tested at 20-24 weeks of gestation in asymptomatic women to predict spontaneous preterm birth: A) <28; B) <32; C) <34; D) <37 weeks of gestation. The area of each circle, rectangle and diamond is proportional to study’s sample size.

Figure 3

Summary receiver operating characteristic (ROC) curves of cervical length tested at 20-24 weeks of gestation in asymptomatic women to predict spontaneous preterm birth: A) <28; B) <32; C) <34; D) <37 weeks of gestation. The area of each circle, rectangle and diamond is proportional to study’s sample size.

Figure 3

Summary receiver operating characteristic (ROC) curves of cervical length tested at 20-24 weeks of gestation in asymptomatic women to predict spontaneous preterm birth: A) <28; B) <32; C) <34; D) <37 weeks of gestation. The area of each circle, rectangle and diamond is proportional to study’s sample size.