The efficacy of sonographically indicated cerclage in multiple gestations

Objective. The purpose of this study was to determine the efficacy of sonographically indicated cerclage in multiple gestations with sonographic evidence of short cervical length (CL). Methods. Between 1996 and 2002, all multiple gestations undergoing serial CL determinations in the second trimester were identified in 2 separate institutions. Cervical lengths were measured sonographically with transvaginal probes (4-8 MHz). Short CL was defined as a closed CL of 2.5 cm or less. When a short CL was identified before 24 weeks, the study group underwent sonographically indicated cerclage via the modified Shirodkar technique; control patients were placed on bed rest without surgical intervention. The primary outcome was incidence of spontaneous preterm birth before 32 weeks. The groups were compared with the Mann-Whitney U test and the Fisher exact test, with a 2-sided P < .05 used to define statistical significance. Odds ratios were calculated, and 95% confidence intervals were reported. Results. A total of 414 sets of twin gestations and 92 sets of triplet gestations were identified. The median gestational age at delivery for twin gestations was 34.0 weeks for patients who received cervical cerclage and 34.4 weeks for patients with short cervix and no cerclage (P = .77). The median gestational age at delivery for triplet gestations was 34.1 weeks for patients who received cervical cerclage and 33.0 weeks for patients with short cervix and no cerclage (P = .21). There was no difference in the rate of spontaneous preterm delivery at fewer than 28, 30, 32, and 34 weeks or in the rate of preterm premature ruptured membranes. Conclusions. In our study of multiple gestations with short CL, sonographically indicated cerclage was not associated with a lower incidence of spontaneous preterm delivery compared with conservative management.