Cone cerclage in pregnancy. We report a technique of cone cerclage and the results and outcome in 17 patients who required a diagnostic cone biopsy in pregnancy. The mean age of the patients was 30.6 years (range 21-41). The mean gestational age was 18.8 weeks (range 10-32) at the time of the procedure. There were no major complications and hemorrhage was not a significant problem. There were no second-trimester abortions. Two patients required beta-sympathomimetics to suppress uterine activity for longer than 24 hours after the procedure. Six patients had invasive carcinoma, nine had cervical intraepithelial neoplasia (CIN) III, and two had CIN II. In 14 cases, the endocervical and ectocervical margins were negative; two patients with CIN and one with multifocal microinvasion had positive margins. Cone cerclage is a safe and easy method for performing diagnostic cervical conization during pregnancy. 