The Information System on Live Births - SINASC - was developed by the Health Ministry and designed to improve quality of information on live births in Brazil. It has been effectively used in Belo Horizonte since 1992. The distribution of live births was analysed in order to characterise them and to allow use of existing data to support planning, organisation and evaluation of the health activities developed. It was conducted by using Declarations of Live Births of newborns of mothers resident in Belo Horizonte, in the period 1992-1994, in terms of characteristics related to labour, pregnancy and mother. We concluded that it is necessary to carry out further analyses on infant and maternal morbidity and mortality and the costs of hospital admission for caesarean section; to give special assistance to teenage mothers; and to offer good quality antenatal care to all pregnant women. SINASC is a powerful information tool and its use should be improved and disseminated, specially its use in specific and differentiated interventions for certain population groups and small risk areas.