Evaluation of the cervix by ultrasound for the prediction of preterm birth.

Across numerous investigations and study populations, the relationship between shortened cervical length and spontaneous preterm birth is consistent and compelling. However, one must recognize the imperfect test characteristics of cervical ultrasound for predicting prematurity, particularly in low-risk populations. It should be clear that this relationship supports interactions with the other anatomic components and interactive pathways that comprise the spontaneous, preterm-birth syndrome. In summary, the clinical usefulness of these observations will be realized only through further investigation into the pathophysiology of spontaneous preterm birth and through controlled, clinical-intervention trials.