To the Editor.
—Magee et al1 recommend wider use of the modified criteria of Carpenter and Coustan2 for the diagnosis and treatment of gestational diabetes mellitus (GDM). Abnormalities of carbohydrate metabolism are likely a continuum, however, requiring treatment of some patients with lesser degrees of intolerance at the expense of others not requiring therapy. Langer et al3 recommend therapy for those with one abnormal value on the 3-hour glucose tolerance test (GTT) using the National Diabetes Data Group (NDDG) values, since this group had an adverse perinatal outcome if left untreated. In comparison with those with a normal 1-hour glucose screen, Leiken et al4 noted a significantly higher frequency of macrosomia in those with an abnormal 1-hour glucose screening test though their 3-hour tests were "normal" by the modified criteria. Included in this normal group and not analyzed separately, however, were 16.8% of the study patients
Bruce L. Ring. Screening for Gestational Diabetes. JAMA. 1993;270(3):324. doi:10.1001/jama.1993.03510030048029