Screening for gestational diabetes: usefulness of clinical risk factors

Objective There is little consensus regarding selective or universal screening for gestational diabetes. The aim of this study is to determine the influence of risk factors on incidence of GDM in Iranian population by using 75 g OGTT. Methods At the first prenatal visit, 924 pregnant women were assessed for age, BMI, obstetric history, family history of diabetes, and diagnosis of polycystic ovary syndrome before pregnancy. All eligible women underwent 2-h 75 g oral glucose tolerance test. Gestational diabetes was diagnosed according to American Diabetes Association criteria. Results During study period, 68 [7.4% (95% CI 5.9- 9.2)] cases of GDM were found. Age, pre-pregnancy BMI, and family history of DM were the independent clinical predictors of GDM. In women with age <25, BMI <= 24.9, and negative family history for diabetes, the risk of GDM was 0.008 (0.001-0.044). This risk increased to 0.250 (0.102-0.495) in women with age >= 30, BMI >= 30 and positive family history for diabetes. With selective screening and without screening in low risk group, we will do 13.6% (126 of 924) less screening tests while missing potentially 1.5% (1 of 68) of GDM cases. Conclusion Age, BMI, and family history of diabetes were independent risk factors in developing gestational diabetes. Concerning these factors, we do not miss substantial number of GDM cases with selective screening.