What is the glucose tolerance test like?

What is the glucose tolerance test like?

For 8 to 14 hours before the test, you can't eat or drink anything but sips of water, so you'll want to schedule it for first thing in the morning. (Don't smoke or exercise either.) For three days before the test, you'll be told to eat at least 150 grams of carbohydrate a day. (If you eat a normal diet and have an extra piece of bread at each meal, you'll likely be getting enough carbs.)

When you arrive for the test, the technician will take a blood sample to measure your fasting blood glucose level and then ask you to drink either a more concentrated dose or a larger volume of the glucose solution (containing 100 grams of glucose). Then brace yourself for three more arm pricks as they test your blood every hour for the next three hours. (You'll definitely need a source of distraction this time, as you'll have to stay seated in the waiting room between blood drawings. You might also want to bring a sandwich, so you can eat right after your final blood sample is drawn. You'll most likely be quite hungry.) The technician should alternate arms each time she draws your blood.

If one of the readings is abnormal, you may have to take another test later in your pregnancy. Or your practitioner may ask you to make some changes in your diet and exercise routine. If two or more of your readings are abnormal, you'll be diagnosed with gestational diabetes and you'll need to talk to your practitioner about a treatment plan. This chart shows the levels that the American Diabetes Association considers abnormal at each interval of the test:

Interval	Abnormal reading
Fasting	95 mg/dl or higher
One-hour	180 mg/dl or higher
Two-hour	155 mg/dl or higher
Three-hour	140 mg/dl or higher