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  • Q&A with Australian Health Practitioners

    What is a glucose challenge test?

    My obstetrician recently told me that at my next visit I would have to take a glucose challenge test to check for gestational diabetes. What does this involve?
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  • 5


    Rebecca Charlotte Reynolds, PhD (Dr Bec) Personable and ethical registered nutritionist (RNutr) and lecturer at UNSW Australia in lifestyle and health. Regular consultant to the … View Profile


    There is some good information here on what a glucose challenge test is:

    Testing your metabolism of blood sugar (glucose) is important when pregnant to test for gestational diabetes.

    Good luck with your appointment :) Dr B

    Information copied from above website below:Diagnosis
    Most women are diagnosed using a special test, which requires a blood sample to be taken after a glucose drink. These tests are usually performed at about week 24 into the pregnancy, or earlier if the woman is at high risk. There are two types of tests:

    • Glucose challenge test (GCT) – blood is taken and the glucose level is measured one hour after the drink. If this is above normal, an oral glucose tolerance test is required.
    • Oral glucose tolerance test (OGTT) – involves taking a blood sample after the woman has fasted overnight, a glucose drink is consumed and then a second blood sample is taken two hours later. A diagnosis is based on the results of the OGTT.

  • 5


    Lisa Renn


    Lisa is an APD with 12 years experience, specialising in helping people identify and change habits that impact negatively on their health. Inspiring change, Lisa … View Profile

    Hi there,
    a glucose chanllenge test is a routine test done when women are pregnant. It involves having a fasting blood test then drinking a high sugar(glucose) drink. You will then have your blood sugar level taken via a blood test at one hour and possibly two hours after you ingested the drink.
    If your blood sugar reading is high after you take the drink then you will be diagnosed with gestational diabetes and be recommended to the care of a diabetes educator/ dietitian and possibly endocrinologist.
    It is important that blood sugar levels are managed well in pregnancy as the baby can grow very large due to the abundance of sugar in the maternal blood- this can have health consequences for mother and baby.
    Good Luck
    Lisa Renn
    Accredited Practising Dietitian(APD)
    Body Warfare Nutrition.

  • 6


    Carolien Koreneff

    Counsellor, Credentialled Diabetes Educator (CDE), Diabetes Educator, Psychotherapist, Registered Nurse

    Carolien Koreneff is a Somatic (body-oriented) psychotherapist, Health Coach, Counsellor as well as a Credentialed Diabetes Educator with over 20 years experience. She currently sees … View Profile

    As Rebecca and Lisa already explained, in a Glucose Challenge Test (GCT) you will be given a glucose drink and your blood glucose level will be checked one hour later. This is a standard test that will be performed in all pregnancies and usually takes place at around 28 weeks gestation (or earlier if risk factors are present). The amount of glucose given in a GCT is exactly 50g, one would expect the blood glucose level to rise somewhat, but not too much. A level over 8 mmol/L will usually see you get invited for a Glucose Tolerance Test (GTT); if the level is over 11 mmol/L you will not need the GTT as this level is in the diabetic range even outside of pregnancy. 
    A GTT involves following a carbohydrate rich diet for 3 days, your blood will be taken fasting, one hour after the drink and 2 hours after the drink, which will be 75 g glucose in this instance.
    Normal fasting blood glucose levels in pregnancy are usually less than 5 mmol/l, we would expect your 1 hour result to be under 10 and the 2 hour result should be < 8 mmol/L. If you have any abnormal result(s) you will be referred to an endocrinologist, diabetes educator or your local hospital diabetes centre, so that you can receive more information about gestational diabetes.
    Let us know how you went with your test, so we can guide you through the next phase, if necessary?
    Good luck and all the best for the remainder of your pregnancy!

  • Arlene is a registered practising dietitian, with a private practice in the Eastern Suburbs of Sydney, and has built a strong business over the last … View Profile

    The glucose challenge test measures your body's response to sugar (glucose). The glucose challenge test is done during pregnancy to screen for gestational diabetes — diabetes that develops during pregnancy.
    The glucose challenge test is done in two steps. First you drink a sugary solution. One hour later, your blood sugar level is measured. The results of the glucose challenge test indicate whether you might have gestational diabetes.
    If the test results are above normal, you'll need to have further testing to determine the diagnosis.

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