The first sign that you’ve developed GDM may be glycosuria, or the sudden appearance of glucose in your urine. Virtually every pregnant woman spills a small amount of glucose into her urine, but if your doctor detects significant glycosuria during a routine urine test, she may order a plasma glucose test to measure the level of glucose in your blood. A level of 126 mg/ dl or higher if you had been fasting at the time of the blood test, or 200 mg/ dl or higher if you were not, points to hyperglycemia and gestational diabetes. However, you must have your blood retested on a subsequent day to confirm that diagnosis. Without any obvious signs or symptoms of high blood sugar that suggest GDM, a glucose challenge and/or an oral glucose tolerance test will be performed.
The Glucose Challenge
The glucose challenge is aptly named, because it is indeed a challenge to drink the 50 grams of sugary sweet glucose that you must consume as part of the test. One hour after you’ve drunk the Glucola solution, your blood is drawn. If your serum glucose levels are over 135 to 140 mg/ dl or higher , it’s an indication that your insulin may not be doing the job it’s supposed to, and a three-hour glucose tolerance test is ordered.
The Oral Glucose Tolerance Test (OGTT)
If it was a challenge to drink 50 grams of Glucola, it is a true test of your tolerance (not to mention your intestinal fortitude) to drink the 100 grams of the stuff required for the OGTT. This test is usually administered in the morning because it requires an eight to fourteen hour fast before it is performed. Your blood is taken before you are given the Glucola to drink, and then blood is drawn at one hour, two hours, and three hours later. Fasting levels of 95 mg/dl or higher before the test, 180 mg/dl or higher at one hour, 155 mg/dl or higher at two hours, and 140 mg/dl at three hours suggest GDM. If two or more of these readings are elevated, GDM is diagnosed.
According to the ADA women who are obese and have GDM may benefit from restricting their carbohydrate intake to 35 to 40 percent of their total calories. Studies have shown this can improve fetal outcomes and reduce hyperglycemia.