Low prevalence of large intraventricular haemorrhage in very low birthweight infants carrying the factor V Leiden or prothrombin G20210A mutation

The influence of genetic factors that increase coagulation on the extension of intraventricular haemorrhage (IVH) in very low birthweight infants has not been studied previously. This study investigated the frequency and effect of the factor V Leiden and prothrombin G20210A mutations in a population-based cohort of 305 preterm infants with a birthweight below 1500 g. The overall prevalence of IVH was similar in infants with (n = 43) and without (n = 262) prothrombotic mutations (18.6% vs 16.4%, respectively). However, infants with prothrombotic mutations had a significantly reduced risk of developing extension to IVH grade II or more [p = 0.023, odds ratio (OR) 0.11, 95% confidence interval (CI) 0.02-0.5]. The carrier state of a factor V Leiden or prothrombin G20210A mutation was still predictive for a low rate of IVH grade II-IV if possible confounding variables were included in a multivariate regression model (OR 0.12; 95%CI: 0.017-0.86). Conclusion: The data suggest that the factor V Leiden and prothrombin G20210A mutations lead to improved control of intraventricular bleeding in very low birthweight infants.