Clinical characteristics of women with gestational diabetes - comparison of two cohorts enrolled 20 years apart in southern Brazil: Caraterísticas clínicas de mulheres com diabetes gestacional - uma comparação de duas coortes arroladas em intervalo de 20 anos no sul do Brasil

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/m(2) versus 28 ± 6 kg/m(2); 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.