Cerclage for Short Cervix in Twin Pregnancies: Systematic Review and Meta-analysis of Randomized Trials Using Individual Patient-level Data

Objective: To evaluate the efficacy of cerclage for preventing preterm birth in twin pregnancies with a short cervical length.

Design: We performed an individual patient data meta-analysis. Searches were performed in electronic databases.

Setting: Sidney Kimmel Medical College of Thomas Jefferson University, Philadelphia, PA, USA.

Population: Twin pregnancies in mothers with short cervical length.

Methods: We performed an individual patient data meta-analysis of randomized trials of twin pregnancies screened by transvaginal ultrasound in second trimester and where mothers had a short cervical length <25 mm before 24 weeks. Eligible women had to be randomized to cerclage vs. no-cerclage (control).

Main Outcome Measures: The primary outcome was preterm birth <34 weeks.

Results: Three trials with 49 twin gestations with a short cervical length were identified. All original databases for each included trial were obtained from the primary authors. Risk factors were similar in the cerclage and control groups, except that previous preterm birth was more frequent and gestational age at randomization and delivery were earlier in the cerclage group compared with the control group. Adjusting for previous preterm birth and gestational age at randomization, there were no statistically significant differences in primary (adjusted odds ratio 1.17, 95% confidence interval 0.23-3.79) and secondary outcomes. Rates of very low birthweight and of respiratory distress syndrome were significantly higher in the cerclage group than in the control group.

Conclusion: Based on these Level 1 data, cerclage cannot currently be recommended for clinical use in twin pregnancies with a maternal short cervical length in the second trimester. Large trials are still necessary.