Point: the American Diabetes Association and the International Association of Diabetes and Pregnancy study groups recommendations for diagnosing gestational diabetes should be used worldwide.

Various challenge tests have been used around the world for the diagnosis of gestational diabetes mellitus (GDM), and substantial variation among these methods has been noted, not only in the amount of glucose for the challenge and the testing intervals but also in the concentration thresholds used for interpretation. The interpretive criteria for these testing approaches have variably been based on the value for predicting future maternal diabetes or been adopted from standards developed with nonpregnant individuals, despite the changes in glucose metabolism known to occur during pregnancy. The Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study was an observational study of values obtained in blinded 75-g, 2-h oral glucose tolerance tests (OGTTs) for 23 000 pregnancies from 9 different countries around the world (1 ). The adverse pregnancy outcomes evaluated included birth weight 90th percentile (large for gestational age), fetal hyperinsulinemia, primary cesarean section, neonatal hypoglycemia, neonatal adiposity, shoulder dystocia, and preeclampsia. All adverse outcomes were related directly and significantly to the glucose concentration at each OGTT time point, but there was no obvious inflection point in any of the curves. The International Association of Diabetes and Pregnancy Study Groups (IADPSG) undertook a process to reach consensus on the diagnostic criteria for GDM with respect to their value for predicting adverse pregnancy outcomes and recommended that GDM be diagnosed when one or more of the following plasma glucose values in the 75-g, 2-h OGTT was met or exceeded: fasting, 92 mg/dL (5.1 mmol/L); 1 h, 180 mg/dL (10 mmol/ L); 2 h, 153 mg/dL (8.5 mmol/L) (2 ). According to the HAPO Study data, patients with GDM have an approximate doubling of the likelihood of a baby with a birth weight above the 90th percentile, 2.6 times the likelihood of fetal hyperinsulinemia, twice the likelihood of preeclampsia, and a 40% increase in the likelihood of shoulder dystocia and/or birth injury, compared with pregnancies without GDM (2 ) (Table 1). Admissions to the neonatal intensive care unit also were more common with GDM (9.1% vs 7.8%). The use of the same GDM criteria by caregivers throughout the world makes it possible to compare trends across populations and over time with respect to this condition and to apply results obtained from research in one setting to patients in another setting. Thus far, the IADPSG recommendations have been adopted by the American Diabetes Association, as well as by professional organizations in Japan and Germany, and are being considered throughout the world. At the time of this writing, the American Congress of Obstetricians and Gynecologists has recommended against changing previous practice (3 ). Several concerns have been raised about these recommended criteria for the diagnosis of GDM.