Glucose Tolerance Test (GTT): What you need to know

Posted in Gestational Diabetes and tagged .

Pregnant belly

Ever feel like you get tested for just about everything under the sun while pregnant? Well, you’re not far wrong. One of the benefits of our wonderful health care system is that our doctors and midwives are super vigilant. One of the downsides is that can sometimes mean lots of tests. Today we’re talking about the Glucose Tolerance Test, also known as GTT.

Flat soft drink anyone? If you don’t know yet, trust us you will…

What is it?

Glucose Tolerance Test (GTT)

The glucose tolerance test (GTT) is the gold standard for assessing how your body processes glucose (sugar). The goal is to find out if you have, or are at risk of developing gestational diabetes.

If you’re pregnant in Australia, you will be asked to undergo this test somewhere around the 24-to-28-week mark of your pregnancy.

If you’re already considered to be at risk of developing gestational diabetes, you will be expected to do the test twice. Once early in pregnancy, and again at the normal 24-week mark. Lucky you!

What does the test involve?

If you’ve had friends who are pregnant, you’ve probably heard the test discussed in some not so pleasant terms. And look, we’re not going to talk it up here, it’s probably not one of the most pleasant experiences you’ll have in your life.

You will have to front up at your local pathology centre, early in the morning, on an empty stomach. The first thing they’ll do is take blood sample number one.

After this, you’ll get sent off to sit in the waiting room. This is where the flat soft drink comes in. Hello, Glucose Drink – 75g of pure sugar in around 240mL of liquid form. The pathologist will expect you to down this delightful concoction in 5 mins, and then you wait. You can sip small amounts of water throughout the test.

Your blood will be sampled again at the 1- and 2-hour mark. So that’s 3 blood tests all up.

Then you’re free to go and smash down some food – which you’ll probably be desperate for by the end of all that.

What can I do to prepare?

Pregnant mum relaxing

Not a lot really. Except for the fact that you MUST fast for around 12 hours before your test. Water is ok, but no other liquids or foods, otherwise your test results will be invalid.

You’ll also need to make an appointment for this kind of test. Glucose testing is performed at most of the major pathology centres, but they do need to know you’re coming.

If you have any other underlying health conditions or take any regular medication, you should mention this beforehand.

What are they looking for?

Without getting too scientific, there are some guideline levels that tell the doctors how well your body processes glucose. When the glucose drink hits your empty stomach, your body will start processing it straight away.

Your blood tests are checked against the guideline levels for the specific hour they were sampled. The aim is to see just how much sugar makes its way into your bloodstream. If your levels are too high, there’s a strong chance you either have or will develop gestational diabetes.

What happens if my results are high?

You should hear back from your maternity health care provider within a day or so with your results. If they come back high, it’s definitely not ideal, but it’s also not the end of the world.

Take a deep breath and try not to stress too much. Gestational diabetes is quite common, with around 14% of pregnant women in Australia diagnosed each year.

Depending on the severity of your diabetes, you’ll either be able to manage your sugar levels with a healthy diet and enough exercise, or you may require medication. Rest assured that you’ll be well looked after, and closely monitored for the rest of your pregnancy.

Anything else I should know?

pregnant mum relaxing

The biggest question on every expectant mother’s mind is “is the test safe for my baby?”. The test drink is manufactured to the highest standards and is not harmful in any way to your baby. Gestational diabetes, on the other hand, can be very dangerous if not detected early. So yes, you should definitely do the test.

You might feel a bit average during, and after the test, so take it easy that day. It’s also worth considering getting someone else to drive you if possible.

If you start to feel nauseous, sip some water and try to take your mind off it in any way you can. The bad news is, that if you vomit during the test, you’ll very likely be asked to come back and try again at a later date.

Also, remember you’re going to be sitting in that waiting room for a looooong time. You won’t be allowed to leave the premises at any time during the test. Make sure you bring a book or something else that will keep you occupied for a couple of hours. There’s nothing worse than feeling hungry and/or sick, and not having anything to distract you from it!

Good luck. Remember, it’s only a few hours and then you can run out, grab something to eat and move on with your pregnancy!


What our mums recommend before taking the test

  • Don’t listen to anyone but the nurse administering the test, wasn’t anywhere near as bad as I expected – Amy
  • Go somewhere that will allow you to lay down the drinks always made me feel nauseous and light-headed and that is a horrible feeling when sitting in an uncomfortable chair for two hours – Danielle
  • Don’t book your 20-week scan afterwards. My baby was soo hyper they couldn’t get good pictures or measurements – Kate
  • That you can request to have an hba1c blood test done instead of the GTT and it still gives the same information without having to drink a heap of sugar and wait three hours. – Carol
  • Make sure u drink plenty of water maybe the day before. I was dehydrated so was very hard to get the last set of blood – Linda
  • Book the appointment for first up in the morning so you basically fast during the night – Donica
  • That it wasn’t as bad as I expected due to what I’d been told – Claire
  • Drink it through a straw! Hits the back of the mouth and fewer taste buds – Jasmine
  • The aftermath of coming down from the sugar feels like a hangover – Erin
  • Ask them if it can be chilled makes it way easier to drink – Molly

Read the 300+ comments and find out what other mums recommend to prepare for the GTT.

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