Birth <35, <34, <32, <28, number of days between cerclage and birth
Consistent with the primary outcome, rates of preterm birth before 35, 34 and 32 weeks all were significantly lower in the Shirodkar group. Preterm birth before 28 weeks was the only one of these outcomes to show no difference between the cerclage techniques.
The Shirodkar technique also associated with significantly longer interval between cerclage and birth (mean 10.79 days, CI 8.20-13.38, Table 3).