Cerclage for Short Cervix on Ultrasound in Singleton Gestations Without Prior Spontaneous Preterm Birth: a Systematic Review and Meta-analysis of Trials Using Individual Patient-Level Data.

ObjectiveThe aim of this systematic review and meta-analysis was to quantify the efficacy of cervical cerclage in preventing preterm birth (PTB) in asymptomatic singleton pregnancies with a mid-trimester short transvaginal ultrasound cervical length (TVU CL) and without prior spontaneous PTB. MethodsElectronic databases were searched from inception of each database until February 2017. No language restrictions were applied. We included all randomized controlled trials (RCTs) of asymptomatic singleton pregnancies without prior spontaneous PTB screened with TVU CL, found to have a midtrimester short CLmm, and then randomized to management with either cerclage (i.e. intervention group) or no cerclage (i.e. control group). We contacted corresponding authors of all the included trials to request access to the data and perform a meta-analysis of individual patient data. Data provided by the investigators were merged into a master database specifically constructed for the review. The primary outcome was PTB(RR) with 95% confidence interval (CI). The quality of the evidence was assessed using the GRADE approach. ResultsFive RCTs, including 419 asymptomatic singleton gestations with TVU CL SPTB, were analyzed. No statistically significant differences were found in PTB (21.9% vs 27.7%; RR 0.88, 95% CI 0.63 to 1.23; I2=0%; 5 studies, 419 participants), 2=0%; 5 studies, 126 participants), in women who received tocolytics (17.5% vs 25.7%; RR 0.61, 95% CI 0.38 to 0.98; I2=0%; 5 studies, 154 participants), and in those who received antibiotics (18.3% vs 31.5%; RR 0.58, 95% CI 0.33 to 0.98; I2=0%; 3 studies, 163 participants). The quality of evidence was downgraded two levels because of serious “imprecision” and serious “indirectness,” and therefore was judged as low. ConclusionsIn women with singleton gestation, without prior spontaneous PTB but with TVU CLtrimester, cerclage does not prevent preterm delivery or improve neonatal outcome. Cerclage, in singletons without prior spontaneous PTB, seems to be possible efficacious at lower CLs, such asmm, and when tocolytics or antibiotics were used as additional therapy, requiring further studies in these subgroups. Given the low quality of evidence, further well-designed RCT is necessary to confirm the findings of this study.