Digital examination and transvaginal scan – competing or complementary for predicting preterm birth?

  Background. The transvaginal ultrasonographic cervix scan has partly replaced digital examination for diagnosing preterm birth; conflicting results are reported about their respective contribution to birth prediction. Objective. To review the predictive value of digital examination and transvaginal scan in low‐risk asymptomatic and symptomatic women before treatment. Methods . A literature search of PubMed, Web of Science and Cochrane Databases from 1994 to 2010 and selected reference lists was carried out. Randomized controlled trials, retrospective and prospective cohort studies, outcome research and studies of clinical decision rules were included. Results. The studies showed that methods for the estimation of cervical ripening are not unequivocal nor is the nomenclature for digital examination. Evidence for routine screening for premature cervical ripening in asymptomatic low‐risk women is insufficient. Knowledge of ultrasonographic cervical length in symptomatic women was not associated with a significantly improved outcome in symptomatic women, but may help to reduce length of hospitalization. In women selected by the Bishop Score, a transvaginal scan may reduce the number of false‐positive results. Conclusions. Clarification on the methods for performing cervical assessment is needed. The evidence that transvaginal scanning of the cervix improves outcome in symptomatic women is insufficient. The methods for assessing cervical change should be regarded as complementary.