Ultrasound-indicated cerclage: Shirodkar vs. McDonald

Objective: To compare the efficacy of Shirodkar to McDonald cerclage in patients with singleton pregnancies undergoing an ultrasound-indicated cerclage. Methods: Historical cohort of all patients with singleton pregnancies undergoing cerclage for the indication of a short cervix on ultrasound (ultrasound indicated) at one institution in 2005-2010. We compared outcomes based on cerclage type, Shirodkar or McDonald. Outcome measures were gestational age (GA) at delivery, delivery ≥35 weeks, ≥32 weeks, and PPROM. Multivariable regression analysis was performed to control for significant variables. Results: Seventy-four patients with singleton pregnancies underwent an ultrasound-indicated cerclage in the study period (47 Shirodkar, 27 McDonald). Shirodkar was associated with later GA at delivery (mean GA at delivery 36.98 +/- 3.39 vs. 33.34 +/- 6.37 weeks, p = 0.006), a higher likelihood of delivering ≥35 weeks (83 vs. 55.6%, p = 0.011) and ≥32 weeks (91.5 vs. 59.3%, p = 0.001), and a lower likelihood of preterm premature rupture of membrane (PPROM) (13.0 vs. 46.2%, p = 0.002). On adjusted analysis controlling for differing baseline characteristics, Shirodkar remained significantly associated with an increased incidence of delivery ≥32 weeks (odds ratio [OR]: 5.180, 95% CI: 1.024-26.205). Conclusion: Compared to the McDonald technique, the Shirodkar technique was more effective in prolonging pregnancy in patients with singleton pregnancies undergoing ultrasound-indicated cerclage. A prospective trial is needed to compare these two techniques.