Is There Utility in Transvaginal Cervical Length Surveillance After Cerclage Placement for the Prediction of Spontaneous Preterm Birth?

Introduction: Transvaginal cervical length (TVCL) surveillance post-transvaginal cerclage placement is not universally performed, despite the correlated risk of short TVCL with spontaneous preterm birth (sPTB). This study evaluated if patients with a TVCL <2.5 cm after cerclage placement had higher odds of sPTB than those with a TVCL ≥2.5 cm after cerclage placement.

Methods: This retrospective cohort study included patients with a singleton, non-anomalous gestation with a transvaginal cerclage who had TVCL surveillance post-cerclage placement. The primary outcome was the odds of sPTB among patients with TVCL <2.5 cm vs TVCL ≥2.5 cm after cerclage placement. Transvaginal cerclage placement indications included history indicated, physical exam indicated, and ultrasound indicated. Outcomes were assessed using univariate and multivariate analysis while adjusting for progesterone use, TVCL before cerclage placement, and cerclage indication.

Results: The analysis included 210 patients, and the sPTB rate was 46.7%. Those with sPTB underwent cerclage placement at later gestational ages, had higher rates of exam-indicated cerclage, and were more likely to be prescribed vaginal progesterone. Patients with a TVCL of <2.5 cm after cerclage placement did not have significantly increased odds of sPTB (OR: 2.8, 95% CI: 0.9-8.7, p=0.07); however, patients with a TVCL <2.0 cm had significantly increased odds of sPTB (OR: 6.3, 95% CI: 2.2-18.8, p<0.001).

Conclusion: In patients with transvaginal cerclage, there does not appear to be increased odds of sPTB with TVCL <2.5 cm after cerclage placement; however, there does appear to be an increased odds of sPTB in patients with a TVCL of <2.0 cm after cerclage placement.