Variables associated with the decreased risk of intraventricular haemorrhage in a large sample of neonates with respiratory distress syndrome.

Prematurity and other risk factors are associated with the development of intraventricular haemorrhage (IVH) in newborns with respiratory distress syndrome (RDS). Conversely, further analysis can determine what characteristics might be associated with a decreased risk of IVH.By using International Classification of Diseases, Ninth Revision, Clinical Modification codes from data obtained from the Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project from 2000 to 2009, we identified a large number of cases of RDS. Multivariable logistic regression analysis identified potential variables associated with decreased risk of IVH.Our cohort included 194 621 neonates with RDS, of whom 20 386 (10.5%) developed IVH. Variables associated with decreased risk of both all grades of IVH and severe IVH only included infant of diabetic mother (IDM) status (OR 0.62 (0.54 to 0.70), p<0.001; OR 0.56 (0.42 to 0.74), p<0.001), Trisomy 21 (OR 0.45 (0.30 to 0.69), p<0.001; OR 0.38 (0.16 to 0.93), p=0.034), maternal hypertension (OR 0.62 (0.53 to 0.72), p<0.001; OR 0.28 (0.18 to 0.43), p<0.001), caesarean birth (OR 0.79 (0.74 to 0.84), p<0.001; OR 0.83 (0.73 to 0.94), p<0.001) and, consistent with prior studies, female gender (OR 0.85 (0.82 to 0.88), p<0.001; OR 0.76 (0.72 to 0.80), p<0.001). Polycythaemia (OR 0.67 (0.49 to 0.92), p=0.013; OR 0.79 (0.43 to 1.45), p=0.449) and hypothermia (OR 0.86 (0.75 to 0.99), p=0.039; OR 1.01 (0.81 to 1.28), p=0.903) were associated with lower risk of all IVH but not severe IVH only.Previous associations with IVH such as lower birth weight were confirmed. However, infants in whom new variables such as IDM status were present were less likely to develop all IVH grades. Further analysis of these potential protective variables is necessary to better understand the pathophysiology of IVH.