Factors associated with success of emergent second-trimester cerclage

To assess the factors associated with delivery greater than or equal to 28 weeks' gestation after placement of an emergent cerclage in women with singleton gestations.

All women who underwent emergent cerclage, defined as any cerclage placed between 16 and 24 6/7 weeks' gestation in response to documented cervical change on physical examination, at Northwestern Memorial Hospital from 1980 to 2000 were identified. Univariable and multivariable analyses were used to determine the factors most associated with achieving at least 28 weeks' gestation.

One hundred sixteen women were eligible for analysis. Maternal age, race, and operative variables such as suture type and use of antibiotics were not associated with differences in the frequency of delivery at or after 28 weeks. Cerclage placement at or after 22 weeks' gestation increased the likelihood of reaching 28 weeks, whereas several cervical examination findings (dilatation greater than 3 cm, cervical length less than 0.5 cm, and membranes prolapsing beyond the external cervical os) as well as need for placement in a nullipara significantly reduced the likelihood of reaching 28 weeks. In multivariable analysis, nulliparity (odds ratio 0.31, 95% confidence interval 0.1, 0.8) and membranes prolapsing beyond the external cervical os (odds ratio 0.24, 95% confidence interval 0.1, 0.4) continued to be associated with delivery before 28 weeks, whereas cerclage placement at or after 22 weeks (odds ratio 3.2, 95% confidence interval 1.2, 8.6) increased the chance of achieving at least 28 weeks' gestation.

Nulliparity, the presence of membranes prolapsing beyond the external cervical os, and gestational age less than 22 weeks at cerclage placement are associated with decreased chance of delivery at or after 28 weeks after emergent cerclage; these factors may be used to help counsel patients considering the procedure.