Prediction of cervical cerclage outcome by endovaginal ultrasonography

Abstract

We hypothesized that shortened upper cervical segment length, measured by endovaginal ultrasonography, identifies patients with cervical cerclage at greater risk of preterm delivery. A total of 121 endovaginal ultrasonographic examinations were performed on 32 patients after cervical cerclage. Ultrasonographic measurements included length of the closed cervical canal segments above and below the cerclage and dilatation of the internal cervical os (funneling) with and without fundal pressure. The risk of preterm delivery was tested by Fisher's exact test (two-tailed). Development of funneling of the internal os and shortening of the upper cervical segment length were the most predictive of outcome in patients with cervical cerclage. Twelve patients had shortening of the upper cervical segment (< or = 10 mm) before 30 weeks' gestation (mean 22.6 +/- 2.7 weeks), whereas 20 patients continued to have upper cervical segment measurements > 10 mm. A short upper cervical segment before 30 weeks' gestation was associated with a significantly higher risk of preterm delivery before 36 weeks (58% vs 10%, p = 0.006) and before 34 weeks (50% vs 5%, p = 0.006). Endovaginal ultrasonographic assessment of the cervix in patients with cervical cerclage is a useful adjunct for predicting outcome and for counseling the patient.