The Prenatal Glucose Tolerance Test

If you are pregnant, you will have to undergo a prenatal glucose challenge test around your 24th week. The test is meant to test for gestational diabetes. Gestational diabetes is a form of diabetes that occurs only during pregnancy. If your glucose levels remain high during pregnancy, you may have gestational diabetes. Usually, if you develop gestational diabetes, your glucose levels return to normal after delivery.

During your prenatal glucose tolerance test, you will be asked to drink a sugary drink called Glucola. This drink tastes like a soft drink, usually orange in flavor. Fasting is not required before drinking the Glucola, although you will be asked what and when you ate last. After you drink the Glucola, you will be asked not to eat, drink, or smoke for the next hour. Some women feel lightheaded, tired, or slightly nauseous during the glucose tolerance test for gestational diabetes. These symptoms do not indicate that you have gestational diabetes, however, if you experience these symptoms, be sure to mention it to your doctor. In exactly one hour time, a blood sample will be drawn in order to test for high glucose levels. After the blood test, you will be able to eat or drink as normal.

Usually, the test results will take one to three days to be returned. If you have abnormal glucose tolerance test results, glucose levels above 140 mg/dL, your doctor will call you and usually order a three hour glucose tolerance test. If your results are normal, your results will be reviewed at your next appointment.

The Three Hour Glucose Tolerance Test
If you need to undergo a three hour glucose tolerance test for gestational diabetes, come to the test prepared with something to read, work on, knit, etc. The three hours that you are being tested are long and boring. Some testing facilities will have a room for people undergoing the test to lie down and rest. The three hour glucose tolerance test for gestational diabetes can fatigue you. It is like going through a sugar crash, and you may feel very tired.

The three hour glucose tolerance test is a fasting test. You will be asked not to eat or drink anything (except for water to take medications) for 8 to 14 hours before the three hour glucose tolerance test. Therefore, you will want to schedule the test first thing in morning. Also, make sure that you bring something to eat with you so that you can eat directly after the last blood sample is taken. When you arrive, the technician will take your fasting blood sugar first. You then will be asked to drink a much more concentrated dose of the Glucola. This concentration can cause a "sugar rush" and "sugar crash". Be sure to inform the technician of any symptoms such as dizziness, nausea, vomiting, or fainting spells that you have while waiting. They will want to inform your doctor as soon as possible of these symptoms. After drinking the Glucola, your blood sugar will be drawn from your arm every hour for three hours to determine how your glucose levels vary over time. They will use these numbers to determine if you have gestational diabetes.

You should have someone "on call" for you, in case you are feeling too lightheaded to drive home. This may happen since you have not eaten for upwards of 10 hours.

Results for the test for the three hour glucose tolerance test will take a few days. In the event that your test results are still high, you may be given the diagnosis of gestational diabetes. Your physician will discuss ramification of gestational diabetes for your pregnancy at this time, and most likely will put you on a restricted diet.