Obesity, gestational weight gain, and birth weight in women with gestational diabetes: the LINDA-Brasil (2014-2017) and the EBDG (1991-1995) studies.

OBJECTIVE: This study aimed to evaluate gestational weight gain and birth weight in women with gestational diabetes mellitus of two Brazilian cohorts enrolled three decades apart. METHODS: The authors compared data of 2362 women from the Lifestyle INtervention for Diabetes Prevention After Pregnancy study (LINDA-Brasil, 2014-2017) to those of 359 women from the Estudo Brasileiro de Diabetes Gestacional study (EBDG, 1991-1995). Gestational weight gain was classified by the 2009 Institute of Medicine criteria; large and small for gestational age newborns, by the Intergrowth-21st chart. Differences in birth weight means between pregestational BMI and gestational weight gain categories were evaluated by ANOVA; the associations of gestational weight gain and birth weight, through multivariable Poisson regression. RESULTS: In LINDA-Brasil, women presented higher pregestational BMI (30.3+/-6.5 vs. 24.6+/-4.4kg/m(2)) and were frequently obese (46.4 vs. 11.1%) compared to those of the EBDG. In the EBDG, gestational weight gain was larger (11.3+/-6.1 vs. 9.2+/-7.6kg) and rates of small for gestational age higher (7.5 vs. 4.5%) compared to LINDA-Brasil. In LINDA-Brasil, excessive gestational weight gain was associated to macrosomia (adjusted relative risk [aRR]: 1.59, 95% CI 1.08-2.35) and large for gestational age (aRR: 1.40; 95% CI 1.05-1.86); less gain increased the risk of low birth weight (aRR: 1.66; 95% CI 1.05-2.62) and small for gestational age (aRR: 1.79; 95% CI 1.03-3.11). CONCLUSIONS: These associations were similar in the EBDG, although not statistically significant. Improvements in gestational weight gain and rates of small for gestational age occurred over time in gestational diabetes mellitus pregnancies, accompanied by a worsening in maternal weight profile. This highlights the nutritional transition during this period and importance of avoiding excessive gestational weight gain as well as promoting adequate weight before conception.