McDonald versus Shirodkar cervical cerclage for prevention of preterm birth: a systematic review and meta-analysis of pregnancy outcomes

Objective To compare pregnancy outcomes of patients undergoing either McDonald or Shirodkar cervical cerclage. Methods PubMed, Web of Science, Scopus, and Google scholar were systematically searched up to June 2020. Inter-study heterogeneity was assessed using Cochrane's Q test and the I-2 statistic. Data were pooled using the fixed- or random-effects model and expressed as relative risk (RR) or weighted mean difference (WMD) as appropriately. Results A total of eight observational studies, reporting data on 724 pregnancies, were included in this meta-analysis. As compared to the Shirodkar cerclage, the pooled findings showed that the gestational age at delivery (WMD = -1.95, 95% CI: -2.89 to -1.01, p < .001; I-2 = 57.5%) and birth weight (WMD = -355.69, 95% CI: -413.76 to -297.62, p < .001; I-2 = 28.8%) were significantly lower in McDonald cerclage. The risk of preterm premature rupture of the membranes (PPROM) (RR = 1.76; 95% CI: 1.14 - 2.71; I-2 = 0.0%) and neonatal intensive care unit (NICU) admission (RR = 1.61; 95% CI: 1.09 - 2.39; I-2 = 62.1%) were also higher for McDonald group. However, no significant difference was observed between both groups in terms of cesarean delivery and perinatal/neonatal death. Conclusion McDonald cerclage is associated with a shorter duration of pregnancy, lower mean birth weight and increased risk of PPROM and NICU admission compared to the Shirodkar procedure.