50 Grams Oral Glucose Challenge Test: Is It an Effective Screening Test for Gestational Diabetes Mellitus?

Aim: To find out whether 50 g oral glucose challenge test (OGCT) is an effective screening test for all pregnant women between 24 and 28 weeks gestation.

Method: A 50 g OGCT test was administered to 307 unselected women at 24-28 weeks of gestation. When venous plasma glucose (VPG) concentration after 1 h was >7.8 mmol/l, OGCT was positive. Women with a positive OGCT underwent 2 h 75 grams oral glucose tolerance test (OGTT) as a confirmatory diagnosis of GDM. When fasting and 2 h post 75 g OGTT values were >5.5 mmol/I and >8 mmol/l, respectively, women were considered diabetic.

Results: We screened 307 women for GDM by OGCT. Total number of women with positive OGCT was 83 (27.03 %). In the low-risk group, total number of women with GDM was 9/168 (5.35 %) while the total number of women with GDM in the high-risk group was 14/139 (10.07 %). There was no significant difference with respect to the total number of women with GDM in the groups.

Conclusions: A 50 g OGCT seems to be an effective screening test for both groups. More cases of GDM can be discovered when universal rather than risk-related screening is applied.