Risk factors for preterm birth and the efficacy of prophylactic cerclage in patients with prior conization

Abstract

Objectives: This study examined the risk factors for preterm birth and the efficacy of prophylactic cerclage in patients who had undergone cervical conization due to cervical intraepithelial neoplasia before pregnancy. Materials and Methods: We reviewed the medical records of all patients who gave live singleton births between May 1996 and April 2009, after having cervical conization. Delivery before 37 gestational weeks was considered as preterm birth. The pregnancy outcomes were analyzed with independent sample T-test, chi-square test, and multiple logistic regression using the SPSS statistical software (version 12.0; SPSS Inc, Chicago, IL).Results: Sixty five cases were found. The mean gestational age at delivery was 37 weeks (SD: 3.5). Eighteen patients (27.7%) had preterm delivery. The type of conization, the volume of specimen, and second trimester cervical length were related to preterm birth (P≤ .001, P= .019, P≤ .001, respectively). In multivariate analysis, only mid-trimester cervical length was statistically significant for preterm birth (P=0.012, odd ratio: 0.194, CI: 0.055~0.693). Six out of 65 patients had undergone prophylactic cerclage, and three (50%) of them had preterm births, while 15 (25%) patients without cerclage had preterm births. Conclusion: The type of conization, the volume of specimen, and second trimester cervical length could be the risk factors for preterm birth in patients who had prior history of cervical conization. Prophylactic cerclage may not be helpful in preventing preterm birth, therefore more careful consideration should be paid in deciding cerclage after conization in prenatal counseling.