[Gestational weight gain and postpartum weight retention: data from the 2015 birth cohort in Pelotas, Rio Grande do Sul State, Brazil].

The study's objectives were to describe the prevalence of gestational weight gain and weight retention at 3 and 12 months postpartum and to identify possible socioeconomic inequalities in adequate gestational weight gain. A longitudinal study was performed with data from the 2015 Pelotas, Rio Grande do Sul State, Brazil, birth cohort. Gestational weight gain was classified according to the US Institute of Medicine guidelines. Weight retention at 3 and 12 months was calculated according to the mother's weight at each period, subtracting pregestational weight. To identify possible inequalities, the study used Slope Index (SII) and Concentration Index (CIX). The sample included mothers with information on the study's outcome (n = 4,102). Prevalence of adequate gestational weight gain was 33.5% (95% confidence interval - 95%CI: 32.1; 35.0). Slight inequalities were observed in the prevalence of adequate weight gain in mothers with less schooling [CIX = 1.88 (95%CI: -0.76; 4.52); SII = 4.27 (95%CI: -0.87; 9.41)] and in mothers belonging to the poorest income quintile- 1st quintile- [CIX = 1.04 (95%CI: -1.60; 3.67); SII = 2.93 (95%CI: -2.06; 7.92)], but these differences were not statistically significant. Mean postpartum weight gain was 2.3kg (standard deviation - SD = 6.4) and 1.4kg (SD = 8.8) at 3 and 12 months, respectively. One-third of the women showed adequate weight gain. The observed inequalities in prevalence of adequate gestational weight gain in women with less schooling and in the poorest income quintile were not statistically significant.