Screening for & Diagnosis of Gestational Diabetes: New Glucose Tolerance Testing Panel Available

November 21, 2014

In 2010, the International Association of Diabetes and Pregnancy Study Groups (IADPSG) recommended a change to the diagnosis and classification of gestational diabetes (GDM) (IADPSG. Recommendations on the diagnosis and classification of hyperglycemia in pregnancy. Diabetes Care 2010;33:676-682.) The changes in screening more accurately reflect the strong associations between maternal hyperglycemia and adverse outcomes, namely macrosomia, excess fetal fat and fetal hyperinsulinemia. Short term risks of macrosomia include difficult delivery and maternal/neonatal damage. The long term risks of macrosomia include development of childhood overweight and metabolic factors that may increase the risk of cardiovascular disease. As the proportion of children developing obesity and diabetes continues to soar, addressing fetal exposure to hyperglycemia after identification of GDM in pregnancy will be important.

The changes in diagnosis of GDM and pre-gestational diabetes are supported by the Endocrinology Society and many practitioners in our area have requested the availability of this panel. However, the American College of Obstetrics and Gynecology endorses the 50 gm screening and 100 gm 3 hour testing. Thus, the way in which an individual patient’s diagnosis of GDM/pre-gestational diabetes is made may depend on which specialty performs the initial screening. The 75 gm OGTT for pregnancy will now be available at Providence to order as Gestational Glucose Test, 2HR (LAB88). See summary table below.

When using the 75 g OGTT, diagnosing gestational diabetes requires only one abnormal value instead of 2 or more as traditionally required with the 3 hour 100 gm test. Additionally, the IADPSG endorsed the diagnosis of pre-gestational diabetes during pregnancy based on fasting plasma glucose, A1C or random plasma glucose levels (please refer to article for details), to be obtained on all women or only high-risk women at the first prenatal visit. This diagnosis of "presumed pre-gestational diabetes" during pregnancy should then be confirmed postpartum.

View printable flyer ›

For more information on this transition contact Dr. Veronica Luzzi, PhD, DABCC at (503) 893-7649 or