Are we regionalized enough?: Early-neonatal deaths in low-risk births by the size of delivery units in Hesse, Germany 1990-1999

Background While agreement exists about the benefits of regionalization for high-risk births, little evidence exists regarding regionalization of low-risk births. The objective of this study was to investigate the impact of regionalization on neonatal survival focussed on low-risk births. Methods Data from the perinatal birth register of Hesse, 1990-1999 were used comprising detailed information about 582 655 births covering more than 95% of all births in Hesse. Outcome events were death during labour or within the first 7 days of life (early-neonatal death). Mortality rates and corresponding 95% CI were calculated according to hospital volume measured by births per year and birthweight categories. Results Birthweight-specific mortality rates were lowest in large delivery units and highest in smaller delivery units. This gradient was especially pronounced within low-risk births and was also confirmed in several logistic regression models adjusting for additional risk factors. A more than threefold mortality risk was observed in hospitals with <500 births/year compared with hospitals with >1500 births/year (odds ratio = 3.48; 95% CI: 2.64-4.58). Further trend analyses indicated that prenatal prevention programmes and the increasing usage of modern prenatal diagnostic procedures have not reduced this gradient in recent years. Conclusions This analysis presents an urgent public policy issue of whether such elevated risk in smaller delivery units is acceptable or if further consolidation of birthing units should be considered to reduce early-neonatal mortality.