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Glucose Tolerance Testing

Most healthcare practitioners routinely recommend a glucose tolerance test (also called a GTT) between 24 and 28 weeks of pregnancy to check for gestational diabetes, a high blood sugar condition that some women get during pregnancy. Between 2 and 5 percent of expectant mothers develop gestational diabetes, making it one of the most common health problems during pregnancy. And because the condition rarely causes any symptoms, testing is the only way to find out whether you have it.

Below are pretest instructions you will need to follow when having your glucose tested. You will be provided with a bottle of Glucola from our office which you must keep refrigerated before drinking.


  • Keep your glucose drink (Glucola) very cold.
  • Do not eat or drink after midnight. You may have water only.
  • Drink the Glucola within two minutes.
  • Drink the Glucola at 8 am, and then be at the office no later than 8:45 am. It is very important that you are on time.
  • After you drink the Glucola, place nothing in your mouth (i.e. no gum, food, water, etc.)
  • Arrive at the office at 8:45 am and we will draw your blood at 9 am.
  • Bring a snack. After the blood draw you can eat if you would like.

If you follow these directions you will decrease your chance of failing this test. Failure means doing a 3-hour glucose tolerance test during which we will have to draw your blood four (4) times as opposed to one.

Please feel free to call the office any time with any questions.

If by chance, it is necessary for you to undergo a 3-hour GTT, you will need to follow a specific diet beforehand. You will come into our office and we will draw a fasting blood sample. You will then follow the instructions for drinking the Glucola as listed above. We will then draw three (3) additional blood samples during the course of the test.

The diet outlined below is specifically prepared for you. It is designed to supply the proper amounts of food needed to obtain an accurate test of how well your body burns carbohydrates. It is very important that you eat at least the amounts shown above on the diet. You may also add to the diet any other food you would like. For example, it is all right to add fruit, fruit juice, butter or jelly for breakfast. At lunch and dinner, it is permissible to add meat, fish, cheese, butter, or salad. Just be certain you eat everything listed on the diet. Snacks are permitted.

Important: Eat the diet as listed daily for three (3) days, plus anything else you desire. Also, you should not eat or drink after 10 pm the night before the test.


  • Cereal (1/2 cup) cooked or dry
  • Bread, white, two (2) slices
  • Skim milk (1 cup)
  • Sugar (2 tablespoons)

Lunch (Noon)

  • Potato (1 medium, 2 ½” diameter)
  • Vegetable (1/2 cup) cooked
  • Bread, white, 2 slices
  • Dessert, pie (one 4” sector of 9” diameter), or cake (2 sectors of a 8” diameter)
  • Sugar (2 tablespoons)
  • A packed lunch may consist of two (2) meat, cheese or egg sandwich, fruit, cake or cookie, and a candy bar.

Dinner (Evening)

  • Follow the same menu as specified for lunch.

Please keep in mind that this is a three hour test. If you have children, it would be best to make child care arrangements.