The implications of sonographically identified cervical changes in patients not necessarily at risk for preterm birth.

Sonography of the cervix and lower uterine segment has been used in evaluating pregnancies at risk for incompetent cervix and premature labor. Shortened cervix (less than 3 cm) and open internal os with funneling of the membranes into the endocervical canal are sonographic features associated with premature delivery. We identified these sonographic signs in a group of 31 asymptomatic women who were undergoing prenatal sonography for multiple indications, not necessarily related to premature labor or cervical incompetence. Nineteen patients (61%) in this heterogeneous population had pregnancies complicated by preterm labor, clinical evidence of incompetent cervix, or preterm birth. We conclude that the presence of abnormal sonographic features of the cervix seen incidentally during prenatal sonography on asymptomatic patients warrants close clinical attention.