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 < or = 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 > or =30, BMI > or = 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.

Comparison of different diagnostic criteria for gestational diabetes mellitus based on the 75-g oral glucose tolerance test: a cohort study.

OBJECTIVE: To compare the different diagnostic criteria for gestational diabetes mellitus (GDM) proposed by the American Diabetes Association (ADA), World Health Organization (WHO), and Australian Diabetes in Pregnancy Society (ADIPS) in a 75-g, 2-hour oral glucose tolerance test (OGTT) and to investigate their effects on neonatal birth weight. METHODS: Healthy pregnant women were enrolled in a cohort study to undergo a 75-g OGTT during 24 to 28 weeks of pregnancy and then followed up to delivery. ADA criteria and recommendations were used for the management of patients. RESULTS: Among 670 pregnant women, GDM was diagnosed in 41 (6.1%), 81 (12.1%), and 126 (18.8%) on the basis of ADA, WHO, and ADIPS criteria, respectively. The kappa value was 0.38 (P<.0001) for the agreement between ADA and WHO criteria, 0.41 (P<.0001) for agreement between ADA and ADIPS criteria, and 0.64 (P<.0001) for agreement between WHO and ADIPS criteria. WHO-only "positive" women had significantly lower fasting plasma glucose (87.9 versus 102.2 mg/dL; P<.0001) and 1-hour plasma glucose levels (146.4 versus 200.5 mg/dL; P<.0001) but higher 2-hour plasma glucose levels (150.1 versus 109.1 mg/dL; P<.0001) than women diagnosed with GDM by only ADA criteria. The correlation coefficient between 1-hour glucose level and neonatal birth weight was 0.09 (P<.02). The adjusted odds ratio of macrosomia associated with GDM according to ADA criteria was 1.34 (95% confidence interval, 0.15 to 12). CONCLUSION: The frequency of occurrence of GDM was 6.1% in a 75-g OGTT based on ADA criteria, and there was fair agreement between ADA and WHO criteria, moderate agreement between ADA and ADIPS criteria, and strong agreement between WHO and ADIPS criteria. A modest correlation was found between the 1-hour serum glucose value and neonatal birth weight.