Change in cervical length after prophylactic cerclage

Objective: To determine changes in length of incompetent cervices after cer clage, using transvaginal ultrasound. Methods: Patients were enrolled in a prospective, observational study under an Institutional Review Board-approved protocol. McDonald or Shirodkar sut ures were placed according to physician preference. Pre- and postcerdage ce rvical lengths were measured within 72 hours of the procedure. At each exam ination, the first measurement was discarded, and a mean of the subsequent three measurements was calculated. Results: Twenty-one Shirodkar and ten McDonald operations were done. The me an (+/- standard deviation) precerclage cervical length was 2.7 +/- 0.9 cm and the postcerclage cervical length was 3.6 +/- 0.9 cm (P < .001, paired t test). Conclusion: Prophylactic cerclage results in measurable increases in cervic al length, which might contribute to the success of the procedure. Further study is needed to determine whether the degree of cervical lengthening aft er cerclage predicts term delivery. (C) 1999 by The American College of Obs tetricians and Gynecologists.