Comparison of the American Diabetes Association and World Health Organization criteria for gestational diabetes mellitus and the outcomes of pregnancy

Two to five percent of pregnancies are complicated by diabetes, of which 90% are classified as gestational diabetes mellitus. The aims and objectives of this study were to analyse the screening and diagnostic procedure for gestational diabetes mellitus (GDM) recommended by American Diabetes Association (ADA) in comparison with the World Health Organization (WHO) criteria and to study the outcome of GDM diagnosed by both the criteria. This prospective study was carried out in the Department of Obstetrics and Gynaecology, JIPMER between August 2006 and July 2008. Three-hundred-and-fifty antenatal cases of gestational age >= 24 weeks attending the outpatient department, with any one of the risk factors for GDM, were included in the study. A seventy-five gram oral glucose tolerance test (GTT) was performed on each subject. Results were interpreted using both ADA and WHO criteria. Antenatal complications of GDM, mode of delivery, intrapartum or postnatal maternal and neonatal complications in cases diagnosed with GDM by either criterion were noted. The data collected were analysed using the SPSS software program. The prevalence of GDM was 4% by ADA criteria versus 19.4% by WHO criteria. The diagnostic pick-up rate was approximately five times more with WHO than with ADA criteria. In total, 43% (ADA) and 29% (WHO) of GDM cases had antenatal complications. Seventy-four percent of mothers with macrosomic babies were identified by WHO criteria whereas only 26% of mothers with macrosomic babies were diagnosed by ADA criteria. ADA criteria identify more severe cases of GDM but mild cases diagnosed by WHO are missed. The GTT by WHO criteria was abnormal in a greater percentage of women with adverse outcomes especially macrosomia, than the GTT using ADA criteria.