Background Intraventricular haemorrhages (IVH) greatly impact the outcome of very low birth weight (VLBW) infants. This study examines the correlation between inter-hospital transport and the incidence and severity of IVH in VLBW infants in a large cohort of data.

Methods The US National Inpatient Sample Database (NIS) and its KID subportion were analysed for the years 1997–2004. Infants <1500 g were included in the study and were classified into transport and inborn groups. Groups were further classified according to birth weight into <1000 g and 1000–1499 g. IVH and severe IVH (grades 3–4) were compared between groups and subgroups. Adjusted OR for IVH or severe IVH in correlation with inter-hospital transport were calculated using logistic regression models while controlling for clinical and demographic confounders. We examined changing trends of the incidence of IVH, incidence of neonatal transport and OR for IVH in correlation with neonatal transport in VLBW infants over the years.

Results A total of 67 596 VLBW infants were included in the study. Overall incidence of IVH in the sample was 14.7%; the transport group had more IVH compared to inborn group (27.4% vs 13.42%): adjusted OR 1.75 (95% CI 1.64 to 1.86; p<0.001). Severe IVH was higher in the transport group compared to the inborn group (44.1% vs 32.9%); adjusted OR 1.44 (95% CI 1.22 to 1.70, p=0.001). Similar results were demonstrated in weight-based subgroups. There was increasing trends for neonatal transport and for IVH over the years (p<0.001 for both) with no significant change in the OR for IVH in transported infants.

Conclusion Inter-hospital transport of VLBW Infants is correlated with increased incidence and severity of IVH. This correlation has remained constant over the recent years.