Despite the importance of birth registration for calculating many health indicators, under-registration of births is still very high in Brazil, 31.5% in 1999. After birth registration became free, few studies were conducted to estimate the rate of unregistered births, especially in rural areas, where under-registration is much higher. This study was conducted during PITS (Program of Interiorization of Work in Health) activities in the municipality of Centro Novo do Maranhão, in a state with the highest rate of unregistered births. A cluster sample of 1,157 people was studied by means of a household survey using a questionnaire to estimate the rate of unregistered births, the time elapsed between the birth and its registration, to evaluate registration according to sex, age, schooling of the head of the family and family income, and reasons for not registering. The rate of unregistered births was 8.6% (95% Confidence Interval 7.0% to 10.3%). 95% of the registrations were performed after the period within which it is legally required in rural areas (within 105 days of birth). The mean time between the birth and its registration was 13.1 years. Cohorts born after the registration became free were registered earlier (0.7 year) than those born before (15.2 years). There were no associations between registration and sex or family income. Low schooling was marginally associated with higher rates of under-registration and higher rates of registration after the period within which it is required. Under-registration was higher among under-one-year-olds (25%) whereas registration after the period within which it is required predominated among adults. The main reasons for not registering were "lack of interest of the parents" and "the father did not recognize fatherhood". The rate of unregistered births was lower than expected due to mass campaigns that increased access to free registration, even after the period within which it is legally required.
Live borns; Birth registration; Under-registration of births
