Gestational 'impaired glucose tolerance': Should the cut-off be raised to 9 mmol l-1?

Abstract

It has been suggested that the diagnostic criterion for the 2-h value of the 75 g oral glucose tolerance test in pregnancy be raised to 9 mmol l-1. In order to determine whether patients with a 2-h value of between 8 and 8.9 mmol l-1 should be classified as normal, we performed a retrospective study on patients with gestational diabetes mellitus treated with diet only who delivered within 1 year, and categorized them into three groups according to the 2-h value as follows: group A (8-8.9 mmol l-1), group B (9-10.9 mmol l-1), and group C (≤11.0 mmol l-1). These groups were compared with a control group with normal oral glucose tolerance test results and who delivered within the same 1-year period. Group A patients were significantly different from the control group in maternal age, parity, fasting value in the oral glucose tolerance test, maternal body mass index, gestational age at delivery, incidence of large for dates infants, and placental weight, but were similar to group B for most of these parameters. Group C was significantly different from both the control group and group A for most of the above parameters. Our results suggest that the current World Health Organization criterion for the diagnosis of gestational diabetes mellitus should be maintained.