Universal vs. risk-factor-based screening for gestational diabetes-an analysis from a 5-Year Portuguese Cohort.

PURPOSE: The criteria to screen for Gestational Diabetes Mellitus are not internationally consensual. In opposition to the universal screening performed in Portugal, certain countries advocate a risk-factor-based screening. We aim to compare obstetric and neonatal outcomes in pregnant women with and without risk factors treated for Gestational Diabetes Mellitus. METHODS: Retrospective and multicentric study of 12,006 pregnant women diagnosed with Gestational Diabetes Mellitus between 2011 and 2015, in Portugal. Gestational Diabetes Mellitus was diagnosed according to the International Association of the Diabetes and Pregnancy Study Groups criteria. RISK FACTORS: body mass index > 30kg/m2, history of Gestational Diabetes Mellitus, history of macrossomic newborn (birth weight > 4000 g) or first-degree relatives with Type 2 Diabetes Mellitus. EXCLUSION CRITERIA: lack of data concerning risk factors (n = 1563). RESULTS: At least one risk factor was found in 68.2% (n = 7123) pregnant women. Pregnant women with risk factors were more frequently medicated with insulin (p < 0.001), caesarean section was more commonly performed (p < 0.001), their newborns were more frequently large-for-gestational-age (p < 0.001) and neonatal morbidity was higher (p = 0.040) in comparison to pregnant women without risk factors. The Diabetes Mellitus reclassification test showed an increased frequency of intermediate hyperglycaemia and Diabetes Mellitus in women with risk factors (p < 0.001). CONCLUSION: Almost one-third of pregnant women would have remained undiagnosed if risk-based-factor screening were implemented in Portugal. Women without risk factors presented fewer obstetric and neonatal complications. However, more than one third required insulin therapy.