Cervical cerclage in asymptomatic women with a short cervix on ultrasound: Clinical efficiency for prevention of preterm birth

Kim, Min Hyoung; Chung, Jin Hoon; Choi, June Seek; Ahn, Hyun Kyung; Han, Jeong Yeol; Ryu, Hyun Mee; Kim, Moon Young; Yang, Jae Hyug

Abstract

OBJECTIVE
To investigate the clinical efficiency of the cervical cerclage for preventing preterm birth in asymptomatic women who showed a shortened cervix at the second trimester ultrasound
METHODS
From January 1996 to December 2005, we retrospectively reviewed the medical records of pregnant women who received routine second trimester ultrasound (16~24 gestational weeks) without abdominal pain or bleeding at Cheil general hospital. Women with a short cervical length < or =25 mm were classified into cerclage and expectant group. Women who received cervical cerclage within 1 week after detection of cervical shortening without any change of cervical length and shape were included in cerclage group. Primary outcome was the frequency of delivery before 34 weeks' gestation. Secondary outcome was the most important risk factor for preterm delivery in pregnant women with short cervix. Chi-square test, t-test, and multiple logistic regression analysis were used for statistical analysis. P<0.05 was considered statistically significant.
RESULTS
The mean gestational age at ultrasound was 21.6 weeks' gestation. A total of 111 women had short cervix, including 26 that were treated by cerclage and 85 managed expectantly. The proportion of preterm delivery before 34 weeks' gestation was higher in the cerclage group [38% (10 of 26)] than that of the expectant group [20% (17 of 85)], but there was no significant difference (P=0.069). In the univariate analysis, funneling (38% vs 16%, P=0.012) and cervical length < or =15 mm (47% vs 15%, P=0.069) were associated with preterm delivery before 34 weeks' gestation. In the multiple logistic regression analysis, a cervical length < or =15 mm had an adjusted odd ratio of 3.7 (95% CI 1.3~10.6) for preterm delivery before 34 weeks's gestation.
CONCLUSIONS
These data suggest that cerclage in asymptomatic woman with a short cervix in the second trimester ultrasound does not prevent preterm delivery before 34 weeks of gestation. Woman with extremely shortened cervical length < or =15 mm needs intensive management for prevention of preterm delivery.