Background and Objectives: Gestational diabetes mellitus (GDM) is associated with significant metabolic alterations, increased maternal and perinatal morbidity and mortality. India falls into high risk ethnic group for diabetes mellitus. The objective of this study is to find out prevalence of gestational diabetes mellitus and to evaluate and compare the occurrence of GDM with and without risk factors. Methods: Sample: 450 pregnant women attending the antenatal clinic, Department of Obstetrics and Gynecology at Basappa Memorial Hospital, Mysore, irrespective of risk factors. • Universal screening done by 50 gm Oral Glucose Challenge Test (OGCT) irrespective of time and meal of the study. • If venous blood sample 140 mg/dl, the screening considered positive. • Confirmation of diagnosis done by standard 100 gm, 3 hr Oral Glucose Tolerance Test (OGTT) as per Carpenter’s and Coustan’s criteria. • Post partum 75gm OGTT at 6 wks as per WHO criteria. Results: Prevalence of GDM in study population is 5.5%. Out of 450 pregnant women screened, 192 (42.7%) were with risk factors and 258 (57.3%) were without risk factors. The commonest risk factors in the study population were, age > 25 years (38%), followed by past history of fetal loss [abortions & IUD] (18.2%), family history of diabetes mellitus (11.11%), obesity (5.56%) and unexplained neonatal loss (2%). Among GDM cases, age > 25 years (48%) followed by obesity and family history of diabetes mellitus (28%) and past history of abortion were seen. In our study 106 (23.56% patients) had positive screening for 50 gms OGCT. Out of 106 patients, 25 (23.58%) patients of screening positive patients had positive OGTT and 68% of GDM patients had risk factors. There were no risk factors noted in 32% of GDM patients and would have been missed if universal screening is not practiced. Interpretation and Conclusion: Universal screening for GDM is superior to selective (risk factor based) screening in detecting more cases, facilitating early diagnosis and is associated with improved pregnancy outcome.

Keywords: Oral Glucose Challenge Test (OGCT); Oral Glucose Tolerance Test (OGTT); Gestational Diabetes Mellitus (GDM).