[Factors associated to the evolution of gestational weight of pregnant women: a multilevel analysis].

OBJECTIVE To assess the influence of socioeconomic, reproductive, and behavioral factors on the evolution of weight during pregnancy. METHODS Body weight was measured prospectively in a cohort of 215 healthy pregnant women attended to by a public prenatal service in the city of São Paulo, between 1997 and 1998. The criteria for inclusion were the following: aged 18 or older and with the beginning of prenatal care at a gestational age or= 4 years, lack of partner, and primiparity cause increases of 3.0 kg, 1.9 kg, 2.3 kg and 2.4 kg in the total weight gain during pregnancy, respectively. CONCLUSIONS Initial BMI, level of education and parity are the maternal characteristics that, along with the marital status, must be taken into consideration in the development of strategies to promote adequate weight gain during pregnancy.