Cervical length screening with ultrasound-indicated cerclage compared with history-indicated cerclage for prevention of preterm birth: a meta-analysis.

OBJECTIVE: To compare pregnancy outcomes in singleton gestations with prior preterm birth that were managed either by cervical length screening with cerclage for short cervical length or history-indicated cerclage. DATA SOURCES AND METHODS OF STUDY SELECTION: Medline, Scopus, and the Cochrane Central Register of Controlled Trials were searched for the terms "cerclage," "randomized trial," and "clinical trial" from 1966 until January 2011. No restrictions for language were applied. We performed a meta-analysis of randomized trials of singleton gestations with prior preterm birth. Management by policy of transvaginal ultrasonography cervical length screening with cerclage placement for cervical shortening was compared with history-indicated cerclage.

TABULATION, INTEGRATION, AND RESULTS: Four randomized trials met inclusion criteria, including 467 women. In women with a singleton gestation and prior preterm birth, cervical length screening with cerclage for short cervical length was associated with similar incidences of preterm birth before 37 weeks (31% compared with 32%, relative risk 0.97, 95% confidence interval [CI] 0.73-1.29), preterm birth before 34 weeks (17% compared with 23%, relative risk 0.76, 95% CI 0.48-1.20), and perinatal mortality (5% compared with 3%, relative risk 1.77, 95% CI 0.58-5.35) compared with history-indicated cerclage. In the transvaginal ultrasound cervical length screening group, 42% developed a short cervical length and received cerclage.

CONCLUSION: Singleton gestations in women with prior preterm birth may be monitored safely with a policy of transvaginal ultrasound cervical length screening as compared with a policy of routine history-indicated cerclage. Cerclage can be reserved for the minority of women who develop a short cervical length.