Gestational Diabetes Testing

Diabetes is a condition in which the body is unable to properly use sugar (glucose) as a source of fuel. As a result, the levels of sugar in the blood become abnormally high. When this condition occurs during pregnancy, it is called gestational diabetes.


Gestational Diabetes Impact


Gestational diabetes affects about 2–10 percent of all pregnancies. It usually begins in the fifth or sixth month of pregnancy and goes away after the baby is born. Risk factors for gestational diabetes include gestational diabetes in a previous pregnancy, obesity, high blood pressure, increasing age and a close relative with diabetes.


Gestational Diabetes Ramifications


Gestational diabetes can result in complications for mother and baby. Women with gestational diabetes are more likely to get high blood pressure or pre-eclampsia. They have an increased chance of needing a Cesarean delivery. Babies of women who have gestational diabetes are more likely to develop jaundice. They also may grow too large, leading to an increased risk of birth trauma.


Complications can be avoided by controlling gestational diabetes. Gestational diabetes can usually be well controlled through a combination of close monitoring, diet, exercise and occasionally the administration of medication.


You will be instructed to go to the lab at your convenience or call to schedule time. The lab will provide the glucose solutions to drink and you will need to remain in the clinic for the duration of the test (about one hour).


Gestational Diabetes Screening Test


Testing for gestational diabetes is usually done between 24 and 28 weeks of pregnancy. If you have risk factors for gestational diabetes, you may be tested earlier. For accurate results, it is very important that you follow these instructions exactly. You do not need to make any dietary changes before the test. You do not need to be fasting for this test.


Day of Test

  1. Report to lab to obtain glucose solution. While at lab, drink the entire bottle within five minutes.
  2. Do not eat or drink after finishing this bottle!
  3. This is a timed blood draw. Note what time you started drinking the glucose solution (50 grams).
  4. Return to the lab 45 minutes after the time you finished drinking solution. Do not leave the building. Notify lab staff if you are leaving the area or if you feel ill.
  5. Once at the lab, tell them you have a "timed draw" and the time you started to drink the glucose solution.
  6. You may wish to bring a protein snack, (i.e., peanut butter sandwich, cheese and crackers), with you to eat after your blood has been drawn. Some people may have symptoms of hypoglycemia (drop in blood sugar). Symptoms include: feeling weak, pale or cold, clammy skin, perspiring, and/or nervousness. The protein snack may help prevent these symptoms.
  7. If you have an appointment, check in like you normally would. If you do not then you are free to go.

If you have any questions, please call your doctor's office before you drink the glucose solution. If you have an abnormal screening test, you will then do the Three Hour Glucose Tolerance Test.


Instructions for Three Hour Glucose Tolerance Test

  1. You should follow an unrestricted diet and consume at least 150 grams of carbohydrates per day for at least three days prior to the test.
  2. You shouldn’t have anything to eat or drink for 8-10 hours prior to the test. Gum, mints, cough drops, even if sugar-free, are not acceptable. You may drink water only.
  3. You shouldn’t smoke before the test.
  4. At the lab:
    • You will have a blood test done as soon as you arrive at the lab.
    • You will then be given 100 grams of glucose solution.
    • After you drink the solution you will not be allowed to eat or drink anything.
    • Your blood will be drawn at one, two and three hours after you drink the solution.
    • You will have to remain in the lab or lab area for the duration of the test. Notify staff if you feel ill.
  5. Bring something to do during this time, (i.e., books, work, puzzles, etc.).

We recommend that you bring a protein snack with you to eat after the last blood draw is completed. Some people may have symptoms of hypoglycemia (drop in blood sugar). The symptoms may include feeling weak, pale or cold; having clammy skin, perspiring and nervousness. The protein snack may help prevent these symptoms.