Association of Cervical Length and Term Delivery after Elective Cerclage in Women with High Risk of Preterm Delivery

Abstract

Objective: To analyze the association between cervical length (CL) and term delivery after elective cerclage in women with high risk of preterm delivery. Methods: Medical records of 97 women with high risk of preterm delivery who underwent McDonald elective cerclage and delivered by a single surgeon between January 2003 and June 2012 were reviewed and analyzed. The subjects were grouped according to their preoperative CL as measured by ultrasonography, in which 2.5 cm was defined as short cervical length (SCL). We compared the clinical outcomes according to the SCL (≤2.5 cm vs. >2.5 cm) and predicted the optimal postoperative CL for term delivery after 37 weeks. Results: Postoperative CL significantly differed (2.8 cm vs. 3.3 cm, P=0.003) by the SCL (n=40, n=57), while gestational age at delivery did not differ significantly between the two groups. Two thirds of the subjects who had postoperative CL longer than 3.1 cm maintained pregnancy until 37 weeks (sensitivity: 64%, specificity: 65%). After adjusting for confounding factors, we found that postoperative CL longer than 3.1 cm was associated with an average gestation period of 37 weeks or more (odds ratio=2.6, 95% confidence interval 1.2-6.0). Conclusion: Postoperative CL over 3.1 cm was associated with term delivery after 37 weeks.