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Glucose Tolerance Testing (GTT) in Pregnancy


Updated May 16, 2014

Blood Draw in Lab

The glucose tolerance test (GTT) is standard for most practitioners.

Photo © iStockPhoto

Why the test is done:

This test is done to determine if you suffer from gestational diabetes or glucose intolerance of pregnancy.

How the test is done:

This test can be done fasting or non-fasting, with blood drawn from finger sticks or from your veins.

You may be asked to drink a special sugar enhanced drink called Glucola, eat jelly beans, or a specific breakfast, candy bar, etc. Your blood will then be tested for the level of glucose.

When the test is done:

It is usually offered to most women around 28 weeks gestation. However, if you have a family history of diabetes or had gestational diabetes in a previous pregnancy they may test you earlier. There are also guidelines that say not everyone needs to be tested for gestational diabetes, though it is routine in many places.

How the results are given:

140 and below are considered not gestational diabetics, anything above this reading will usually be sent for further testing.

Risks involved:

There are no risks involved in testing. This is a fairly non-invasive test requiring only blood from the mother. Some women are concerned, rightfully, about the effects on a bolus of glucose to a baby who has not been used to receiving it is such quantities.


Not testing or assuming you are glucose intolerant and beginning dietary precautions.

Where do you go from here?

If you "fail" the one hour test you will be asked to take the three hours glucose test. You will have your blood drawn, be asked to drink or eat something with sugar and will be tested at 30 minutes, one hour, two hours, and three hours. You must pass in three of these tests to "pass" the entire test.

If you "fail" the three hour test you will more than likely be sent to a nutritionist to learn ways that you can control your glucose levels through diet. You will also have a plan for monitoring blood sugar levels to assess your progress.

Other Resources:

  1. About.com
  2. Health
  3. Pregnancy & Childbirth
  4. Prenatal Care
  5. Prenatal Tests
  6. Testing for Gestational Diabetes
  7. Glucose Tolerance Testing (GTT) in Pregnancy

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