Effectiveness of cervical cerclage for a sonographically shortened cervix: a systematic review and meta-analysis.

OBJECTIVE The purpose of this study was to determine the effectiveness of cerclage for a shortened cervix on transvaginal ultrasound scanning in terms of the rates of preterm delivery and adverse neonatal and maternal outcomes. STUDY DESIGN Pre-MEDLINE and MEDLINE, EMBASE, and the Cochrane Library were searched for human studies that compared cerclage placement to no cerclage on the basis of transvaginal ultrasound findings of a short cervix (< or =2.5 cm). Two authors independently determined eligibility and abstracted data. Meta-analyses were conducted when possible. RESULTS Thirty-five studies were reviewed; 6 studies were eligible and were included in the analysis. There was no statistically significant effect of cerclage on the rates of preterm delivery (<37, <34, <32, and <28 weeks of gestation), preterm labor, neonatal mortality or morbidity, gestational age at delivery, or time to delivery. Birth weight was significantly higher with than without cerclage (P=.004). CONCLUSION The available evidence does not support cerclage for a sonographically detected short cervix. A randomized controlled trial is needed to determine whether this intervention will reduce adverse neonatal outcomes.