Objective: The spatial distribution of neonatal mortality by age-group (0-23 hours, 1-6 days and 7-27 days) in the State of Rio de Janeiro, Brazil, for two periods of time 1979-81 and 1990-92, is analysed.
Methodology: A methodology was used to perform the spatial analysis which took the counties of Rio de Janeiro as the spatial units and "first-nearest-neighbors" as the neighborhood criterion. For the purpose of detecting anisotropy, the connection matrix was defined through "first-nearest-neighbors" in a particular direction. To understand the spatial behavior of neonatal mortality, social and environmental indicators and indicators of medical assistance by county for both periods of time were constructed.
Results and conclusions: At the beginning of the 80's, the neonatal mortality for the age group 7-27 days showed the presence of clusters in the East and Southeast in direct association with the poorest conditions of life in the State, characteristics that had vanished by the next decade. Spatial dependence for the mortality rates for the first day of life, for 1991, was identified clusters in two different regions beings detected, followed by a positive correlation with "number of private hospital beds per inhabitant". Some of the cluster counties were, in particular, death receivers from neighboring counties and showed hospital case fatality rates much greater than the overall mean rate.