Objectives: to describe the tendency over time of characteristics of the mother, care provided and newborns, in Niterói, a city in the Brazilian State of Rio de Janeiro.Methods: an ecological time-series study from 2000 to 2009. Data were gathered from the Live Birth Information System (SINASC). Annual variations were described in age, schooling and reproductive history of mother, prenatal care, kind of delivery, color, birth weight and gestational age.Results: the completeness of information was high among the 62,449 live newborns studied. Births fell and primiparity increased. There was reduction in pregnancies among adolescents (2.3% per year) and an increase in mothers aged over 35 years. Schooling improved, with a decrease in the percentage of pregnant women with less than eight years of school. Around 80% of women had attended seven or more prenatal sessions. Caesarean births tended to increase in frequency, with 67.7% of woman having one of these in 2009. Low birth weight showed a tendency to fall by 1.1% per year. Prematurity increased by 7.4 to 7.9%.Conclusions: there were positive demographic and social changes in Niterói. Birth weight was not much affected by prematurity. As in other locations in Brazil, there has been an increase in the number of women undergoing Caesarian sections.