ABSTRACT Objective Our objective was to evaluate gestational weight gain (GWG) patterns and their relation to birth weight. Subjects and methods We prospectively enrolled 474 women with gestational diabetes mellitus (GDM) at a university hospital (Porto Alegre, Brazil, November 2009-May 2015). GWG was categorized according to the 2009 Institute of Medicine guidelines; birth weight was classified as large (LGA) or small (SGA) for gestational age. Adjusted relative risks (aRRs) and 95% confidence intervals (95% CIs) were determined. Results Adequate GWG occurred in 121 women [25.5%, 95% CI: 22, 30%]; excessive, in 180 [38.0%, 95% CI: 34, 43%]; and insufficient, in 173 [36.5%, 95% CI: 32, 41%]. In women with normal body mass index (BMI), the prevalence of SGA was higher in those with insufficient compared to adequate GWG (30% vs. 0%, p < 0.001). In women with BMI ≥ 25 kg/m2, excessive GWG increased the prevalence of LGA [aRR 2.58, 95% CI: 1.06, 6.29] and protected from SGA [aRR 0.25, 95% CI: 0.10, 0.64]. Insufficient vs. adequate GWG did not influence the prevalence of SGA [aRR 0.61, 95% CI: 0.31, 1.22]; insufficient vs. excessive GWG protected from LGA [aRR 0.46, 95% CI: 0.23, 0.91]. Conclusions One quarter of this cohort achieved adequate GWG, indicating that specific ranges have to be tailored for GDM. To prevent inadequate birth weight, excessive GWG in women with higher BMI and less than recommended GWG in normal BMI women should be avoided; less than recommended GWG may be suitable for overweight and obese women.

RESUMO CONTEXTO E OBJETIVO: Prevalência e características do diabetes mellitus gestacional (DMG) modificaram-se com o tempo, refletindo transição nutricional e diferentes critérios diagnósticos. Nosso objetivo foi avaliar características de gestações com DMG em intervalo de 20 anos. TIPO DE ESTUDO E LOCAL: Comparação de duas coortes gestacionais arroladas em diferentes períodos, em hospitais universitários de Porto Alegre, Brasil: 1991 a 1993 (n = 216) e 2009 a 2013 (n = 375). MÉTODOS: Aplicamos dois critérios diagnósticos às coortes: International Association of Diabetes and Pregnancy Study Groups (IADPSG)/Organização Mundial de Saúde (OMS); e National Institute for Health and Care Excellence (NICE). Comparamos características e desfechos materno-fetais entre as coortes e dentro de cada uma. RESULTADOS: Na coorte dos anos 2010, as mulheres eram mais velhas (31 ± 7 versus 30 ± 6 anos), obesas (29,4% versus 15,2%), apresentaram mais distúrbios hipertensivos (14,1% versus 5,6%) e risco aumentado de cesariana (risco relativo ajustado 1,8; intervalo de confiança de 95% 1,4 - 2,3), comparadas às da coorte de 1990. Desfechos neonatais, como categoria do peso ao nascer e hipoglicemia, foram semelhantes. Na coorte de 1990, essas características e desfechos foram semelhantes nas mulheres que preenchiam apenas um dos critérios; na de 2010, mulheres diagnosticadas apenas pelo IADPSG/OMS eram mais obesas (33 ± 8 kg/m2 versus 28 ± 6 kg/m2, P < 0,001) do que as diagnosticadas apenas pelo NICE. CONCLUSÃO: A epidemia de obesidade parece ter modificado o perfil de mulheres com DMG. Embora desfechos neonatais sejam semelhantes, houve diferenças na intensidade de tratamento ao longo do tempo. O critério da IADPSG/OMS parece identificar um perfil mais associado à obesidade.

ABSTRACT CONTEXT AND OBJECTIVE: The prevalence and characteristics of gestational diabetes mellitus (GDM) have changed over time, reflecting the nutritional transition and changes in diagnostic criteria. We aimed to evaluate characteristics of women with GDM over a 20-year interval. DESIGN AND SETTING: Comparison of two pregnancy cohorts enrolled in different periods, in university hospitals in Porto Alegre, Brazil: 1991 to 1993 (n = 216); and 2009 to 2013 (n = 375). METHODS: We applied two diagnostic criteria to the cohorts: International Association of Diabetes and Pregnancy Study Groups (IADPSG)/World Health Organization (WHO); and National Institute for Health and Care Excellence (NICE). We compared maternal-fetal characteristics and outcomes between the cohorts and within each cohort. RESULTS: The women in the 2010s cohort were older (31 ± 7 versus 30 ± 6 years), more frequently obese (29.4% versus 15.2%), with more hypertensive disorders (14.1% versus 5.6%) and at increased risk of cesarean section (adjusted relative risk 1.8; 95% confidence interval: 1.4 - 2.3), compared with those in the 1990s cohort. Neonatal outcomes such as birth weight category and hypoglycemia were similar. In the 1990s cohort, women only fulfilling IADPSG/WHO or only fulfilling NICE criteria had similar characteristics and outcomes; in the 2010s cohort, women only diagnosed through IADPSG/WHO were more frequently obese than those diagnosed only through NICE (33 ± 8 kg/m2 versus 28 ± 6 kg/m2; P < 0.001). CONCLUSION: The epidemic of obesity seems to have modified the profile of women with GDM. Despite similar neonatal outcomes, there were differences in the intensity of treatment over time. The IADPSG/WHO criteria seemed to identify a profile more associated with obesity.