Why am I being offered a glucose tolerance test (GTT)?
Glucose tolerance testing during pregnancy helps us check for gestational diabetes, which is high blood sugar that some people get during pregnancy. Gestational diabetes can affect your health and your baby’s health.
If you have a higher chance of developing gestational diabetes, we offer a glucose tolerance test, usually between 24 and 28 weeks of pregnancy. If you’ve had gestational diabetes in a previous pregnancy, we will offer the test around the time of your dating scan and again at 24 to 28 weeks of pregnancy.
It’s important to go to your glucose tolerance test at the right time in your pregnancy to make sure the results are accurate and reliable.
Who is offered a glucose tolerance test?
You might be offered this test if you have certain risk factors, such as:
- Having a family history of diabetes in a close relative
- Being overweight
- Having an ethnic origin with higher diabetes prevalence
- Having had gestational diabetes in a previous pregnancy
The glucose tolerance test is simple, safe and is the recommended method of screening for gestational diabetes in pregnancy.
Preparing for your test
If you choose to have the test, you’ll need to fast overnight. This means having no food or drink except water from midnight before the test.
It’s recommended that you do not chew gum or smoke on the morning of the test.
What happens during the test?
On the morning of the test, you’ll come to the antenatal clinic at St James’s Hospital or Leeds General Infirmary.
First, a blood sample will be taken to measure your fasting blood sugar level.
Next, you’ll drink a sweet sugary solution over 5 to 10 minutes.
After drinking the solution, you’ll sit and wait in the clinic for about 2 hours and continue to not eat or drink anything other than plain water. Sitting still after the first blood test is important for testing accuracy, so it’s a good idea to bring something to read or do while you wait.
Two hours later, we’ll take your blood again to see how your body has processed the sugary drink.
Getting your results
After the test, you can eat and drink normally.
We’ll review your results and let you know if you have gestational diabetes, usually within five working days. If you do, we’ll work with you to manage it with a healthy diet, exercise and sometimes medication.
Remember, the glucose tolerance test is an important step in keeping you and your baby healthy. If you have any questions, don’t hesitate to ask your midwife or doctor.