Cervical Cerclage Placed Before 14weeks Gestation In Women With One Previous Midtrimester Loss: A Population-Based Cohort Study

BackgroundCervical cerclage is used in an attempt to reduce recurrence risk of preterm birth, but evidence for use is limited.AimsTo compare pregnancy outcomes among women with a single previous midtrimester delivery when managed with or without a cervical cerclage.Materials and methodsPopulation-based cohort study of all women in New South Wales, Australia with a singleton pregnancy ending in birth/miscarriage 14 and <28weeks, between 2003 and 2011. Modified Poisson regression was used to compare outcomes in the next subsequent pregnancy, for women with a cerclage inserted <14weeks, and those without cerclage. The primary outcome was gestational age <37weeks at birth/miscarriage in the next pregnancy. Secondary outcomes included: maternal morbidity, preterm prelabour rupture of membranes (PPROM), stillbirth/neonatal death and composite neonatal morbidity for liveborn infants 28weeks. Adjusted risk ratios (ARR) and 95% confidence intervals (CI) were determined.ResultsFive thousand, six hundred and ninety-eight births/miscarriages were potential index deliveries. Of these, 2175 women had an eligible subsequent pregnancy: 108 received cerclage at <14weeks gestation, 2067 did not. Women with cerclage were significantly more likely to deliver <37weeks than those without (39.8% vs 19.3%, ARR 1.92, 95% CI 1.48-2.48), and had increased risks of PPROM (ARR 4.38, 95% CI 2.62-7.32) and stillbirth/neonatal death (ARR 2.20, 95% CI 1.02-4.73). Following cerclage, liveborn infants 28weeks had double the risk of severe morbidity (ARR 2.54, 95% CI 1.55-4.16).ConclusionsIn women with a single previous midtrimester delivery, cervical cerclage <14weeks gestation in subsequent pregnancy was associated with worse pregnancy outcomes.