The glucose tolerance test is used to test pregnant women for potential gestational diabetes, which is pregnancy-induced diabetes. The American Diabetes Association states that gestational diabetes occurs in as many as 9.2 percent of pregnancies according to a study conducted in 2014. Gestational diabetes risk factors include prior pregnancies with gestational diabetes, having type 1 or 2 diabetes, a family history of diabetes, a body mass index (BMI) of over 30, and advanced maternal age.
Pregnant women receive an initial screening between 26-28 weeks which is referred to as the glucose challenge screening. For the glucose challenge screening, you do not need to fast, but most doctors recommend you eat a high protein breakfast and limit your sugar intake the morning of the test. For the test you are given a small bottle of glucose, a really sweet drink, and then one hour from finishing the drink your blood will be drawn to test the blood glucose levels. If your glucose levels are high, this may indicate your body is not processing sugar well and would indicate that the glucose tolerance test is needed.
If the test results for the glucose challenge screening come back positive, the second test referred to as the glucose tolerance test is typically performed. This test is the final determinant as to whether the woman has gestational diabetes or not. This test has some specific requirements to which you must adhere. For three days prior to the test you must eat a minimum of 150mg of carbohydrates each day. 8 to 14 hours before the test you are not allowed to eat or drink anything but the occasional sip of water. It is also recommended that someone drive you to and from the test as you may be light headed from lack of food and after the test from the extreme amount of sugar. The day of the test you will have an initial blood draw to determine your baseline glucose level, then you will be given a more concentrated glucose drink than the one given in the challenge screening. Afterwards your blood is drawn every hour for three hours. You cannot eat until after all three blood draws have been taken.
If your blood draws after the glucose tolerance test are abnormal the doctor may suggest altering your diet or diagnose you with gestational diabetes depending on the severity of the results. The glucose drinks can be difficult to tolerate and can cause lightheadedness, dizziness, nausea, stomach pain, diarrhea, and/or constipation. If you are against drinking the glucose drink then you can ask your doctor or midwife if one the following alternatives is an acceptable option: ¼ cup of pure maple sugar, 1 banana with a glass of orange juice, 28 jelly beans, or a small bottle of white grape juice.
If you have any questions about the glucose challenge screening or the glucose tolerance test feel free to leave a comment. Next week I will blog about the letter H… H is for Hospital Bag.