Comparison of diagnostic criteria of IGT, borderline, and GDM. Blood glucose curve and IRI response.

A 75-g oral glucose tolerance test (OGTT) was performed in 615 nonobese pregnant women (mean +/- SD age 29.7 +/- 4.3 yr) who were referred to the Division of Internal Medicine at our diabetes center because of glycosuria. Seventy-seven cases were found to have urinary glucose at the first trimester, 185 at the second trimester, and 353 at the third trimester. With their 75-g OGTT results, the diagnostic criteria of borderline (formulated by the Japan Diabetes Society), impaired glucose tolerance (IGT; defined by the World Health Organization [WHO]), and gestational diabetes mellitus (GDM; determined by the Japan Society of Obstetrics & Gynecology standards) were compared through blood glucose (BG) curves and immunoreactive insulin (IRI) responses. Borderline (fasting BG greater than or equal to 6.1 and less than 7.8 mM and 2-h BG greater than or equal to 6.7 and less than 11.1 mM) is neither diabetes nor normal. IGT is as referred to by the WHO. GDM exceeds two points of fasting BG greater than or equal to 5.6 mM, 1-h BG greater than or equal to 10.0 mM, or 2-h BG greater than or equal to 8.3 mM. Diabetes mellitus (DM) is as referred to by the Japan Diabetes Society (same as the WHO). The prevalence of abnormal glucose tolerance among all 615 pregnant women was 54.6% in borderline, 24.5% in IGT, 7.3% in GDM, and 3.4% in DM. The 2-h BG levels in IGT during the first trimester were higher than in borderline (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)