DISPARITY IN DIAGNOSIS OF GESTATIONAL DIABETES MELLITUS USING 75g AND 100g GLUCOSE LOAD TESTS AMONG ANTE-NATAL ATTENDEES AT MADONNA UNIVERSITY TEACHING HOSPITAL, ELELE, RIVERS STATE

Several cases of Gestational diabetes mellitus (GDM) are seen in our working environment and this condition can have substantial impact on fetal growth, birth weight and morbidity. Standard recommendations for GDM testing prescribe the use of either a 3-hour, 100g glucose load (100g) or a 2-hour 75g glucose load (75g). We investigated the comparability of the 75g and the 100g tests in the diagnosis of GDM in our environment. From February, 2007 to January 2010, we performed the GDM testing using a 75g glucose load on 956 consecutive Nigerian non-obese and non-diabetic pregnant women who attended the antenatal clinic of the Madonna University Teaching Hospital, Elele, Rivers State. This testing was carried out during two periods of pregnancy: early (16-24weeks) and late (26-34weeks). All women with 1-hour plasma glucose above 7.2mmol/L in the 75g test were retested using the 100-g glucose load within a week. Gestational diabetes mellitus (GDM) was diagnosed (during the 16-24weeks) in 46 out of 269 women with the 100g and 18 out of 269 with the 75g load (12 concordant); the k index was 0.22. At 26-34 weeks of pregnancy, 388 out of 950 women (40.8%) underwent both tests. GDM was diagnosed in 65 of 388 women with 100g load and in 29 of 388 women with the 75g load (14 concordant); the k index was 0.19.Among women with positive GDM in both early and late periods of pregnancy, there was only weak diagnostic agreement between results determined with 75g and 100g glucose loads.