The inability of the uterine cervix to retain a pregnancy in the second trimester is referred to as cervical insufficiency. Controversy exists in the medical literature pertaining to issues of pathophysiology, screening, diagnosis, and management of cervical insufficiency. The purpose of this document is to provide a review of current evidence of cervical insufficiency, including screening of asymptomatic at-risk women, and to offer guidelines on the use of cerclage for management. The diagnosis and management of other cervical issues during pregnancy, such as short cervical length, are discussed more in-depth in other publications of the American College of Obstetricians and Gynecologists.