Management of cervical weakness based on the measurement of cervical resistance index.

Objective: To assess the value of measuring cervical resistance index (CRI) as an aid to selecting patients with a history of spontaneous mid-trimester miscarriage for cervical cerclage in subsequent pregnancies.

Study Design: An observational study of 175 patients with a history of one or more spontaneous mid-trimester losses and 123 non-pregnant women who had CRI measurements performed while undergoing routine gynaecological surgery. Those women whose CRI indicated an incompetent cervix were recommended for cervical cerclage in future pregnancies while women with a normal CRI were recommended for conservative management without cerclage.