Cervical Insufficiency and Cervical Cerclage

Abstract

Preterm birth causes significant morbidity and mortality among newborns and is a financial burden on the healthcare system. One etiology for extreme prematurity is cervical insufficiency, a mechanical failure of normal cervical function, resulting in painless cervical dilation in the second trimester. The exact mechanism is unknown, but current research suggests that cervical insufficiency is caused by a combination of subclinical infection and inflammation, along with structural changes in the cervical stroma. Cervical changes associated with cervical insufficiency are gradual, beginning with changes occurring at the level of the internal os that lead to cervical shortening and subsequent cervical dilation. There are several risk factors that can be identified by clinical history and physical exam to stratify patients at risk. Cervical shortening is seen using transvaginal or transperineal ultrasonography, and evidence-based guidelines for screening high-risk patients for cervical shortening are available. The treatment for cervical insufficiency is cerclage placement. Deciding which patients benefit from cerclage can be complex and involves consideration of obstetric history, clinical presentation, and cervical length. This review contains 10 figures, 1 table, and 72 references. Key Words: abdominal cerclage, cervical funneling, cervical insufficiency, cervical length measurement, cervical shortening, dynamic cervix, preterm birth, transvaginal cerclage, TYVU progression