Pregnancy outcome after cervical conization: risk factors for preterm delivery and the efficacy of prophylactic cerclage

Abstract

Objective: 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. 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 ver. 12.0. 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 the specimen, and second trimester cervical length were related to preterm birth (p≤0.001, p=0.019, p≤0.001, respectively). In multivariate analysis, only mid-trimester cervical length was statistically significant for preterm birth (p=0.012; odds ratio, 0.194; confidence interval, 0.055 to 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 may be the risk factors for preterm birth in patients who have a 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 during prenatal counseling.

Prediction and prevention of preterm birth after cervical conization

“…10 Shin et al 5 also failed to see the efficacy of cerclage as a preventive method for preterm birth, even after confining analysis to those with short cervix (cervical length of less than 25 mm). In the study of Nam et al, 4 the rate of preterm birth after cerclage was not lower in patients who had undergone prophylactic cerclage than those without. There are several points to be considered in these two articles.…”

“…11 But none of these studies stated the type of cerclage employed. But Nam et al 4 tried to focus on the risk factors for preterm birth, and integrated all associated factors together rather than a single factor, in the largest numbers of Korean patients ever published on this subject. The study of Shin et al 5 has the strength that almost all patients were followed up for antenatal care and delivery after conization in a single institution.…”

“…Berghella et al 7 reported that only 28% had a short cervix in pregnant women at between 16 and 24 weeks after cervical conization. Considering that cervical length is not always shortened after conization, measuring cervical length may be also useful in predicting preterm delivery in pregnant women after conization, as suggested by the study of Nam et al 4 and other recent evidences. …”

“…However, recent studies with larger sample size, systematic review, or meta-analysis have generally found an increased risk of preterm birth after cold-knife conization and LLETZ or LEEP, although the data on obstetric risk after ablative therapy such as cryotherapy or laser vaporization are contradictory. 2,3 In this issue of Journal of Gynecology Oncology, there are two articles 4,5 dealing with the association between cervical conization and preterm delivery. Both studies showed a higher rate of preterm delivery after cervical conization (27.7% and 32.1%) than that in low risk pregnancies.…”

“…Both studies showed a higher rate of preterm delivery after cervical conization (27.7% and 32.1%) than that in low risk pregnancies. The study of Nam et al 4 focused on the prediction of preterm birth by identifying risk factors, and Shin et al 5 tried to evaluate the efficacy of cerclage as a preventive strategy for preterm birth. In the study of Nam et al, 4 the type of conization, the volume of specimen, and second trimester cervical length were the possible risk factors for preterm birth, but only the second trimester cervical length was the significant risk factor after adjusting for confounding variables in multivariate analysis.…”