Fasting may increase heartburn in some pregnant women. if you experience uncomfortable or concerning symptoms of any kind while you’re waiting to have your blood drawn, let your doctor know.
Fasting blood sugar test. this measures your blood sugar after an overnight fast (not eating). a fasting blood sugar level of 99 mg/dl or lower is normal, 100 to 125 mg/dl indicates you have prediabetes, and 126 mg/dl or higher indicates you have diabetes. glucose tolerance test. this measures your blood sugar before and after you drink a.