The 75 and 50g OGTT response in normal pregnant women

The 75 and 50g OGTT (Oral Glucose Tolerance Test) responses were studied in 86 normal healthy pregnant women (mean age 28.7 +/- 0.4 (SEM) years) at 28 and 32 weeks respectively. Of these were 50 Chinese, 20 Malays and 16 Indians. Mean glucose responses at fasting, 1 and 2h post glucose load were 78.3 +/- 0.7, 132.2 +/- 2.8 and 116.2 +/- 2.1 mg/dl respectively for the 75g OGTT and 78.5 +/- 0.7, 130.5 +/- 2.5 and 106.7 +/- 1.8 mg/dl respectively for the 50g OGTT. Except for the 2h responses, corresponding responses between both OGTTs were not significantly different. All races showed a similar OGTT response. Using a set criteria for diagnosis of abnormals resulted in gross inconsistency in the number of abnormals diagnosed for both OGTTs. However, the use of 95th percentile shows a closer agreement in the diagnosis of abnormal cases for both OGTTs. Also, the 2h OGTT response for the 75g OGTT is higher than that of WHO's criteria for impaired glucose tolerance. This emphasizes the need to establish our own reference range.