Introduction In view of the limitations of indirect demographic techniques for infant mortality estimation in Brazil, the current strategy is to improve vital information. This paper presents results of a proactive search of deaths and live births in the Northeast and Amazonia.

Methods We analysed vital information from the mortality and live birth information systems. The adequacy analysis was based on five indicators calculated at the municipality level, per 3-year period, from 1996 to 2008. To complement secondary data analysis, in 2009, a proactive search was carried out in a sample of 133 municipalities in the Northeast and Amazonia, stratified by information adequacy, region and population size of the municipality of residence. Correction factors were calculated by strata and by Brazilian state.

Results Temporal trends of the adequacy indicators indicate advances in both information systems. In 2008, coverage of the mortality information system was 88% and coverage of infant deaths was 79%. However, the proactive search of infant deaths showed large deficiencies of vital information in some poor areas, with only 52% infant deaths informed to the Mortality Information System. The correction factors varied from 1.11 to 1.62, depending on the adequacy of vital information, and from 1.02 to 1.28, by Brazilian state.

Conclusion The monitoring of vital events is an essential step in the process of reducing infant mortality. The analysis of local irregularities not only improves the quality of vital data registration, making possible to estimate the infant mortality rate directly, but also identifies priority areas for intervention.