The Glucose Challenge Test for Gestational Diabetes: What to Expect

You may have heard about the glucose challenge test before and are dreading it. From the length of time it takes, to the drink you have to consume prior, it can seem daunting. Never fear, though – we’ll break it down for you below to put your mind at ease. It’s an extremely important test for gestational diabetes, but going in knowing what to expect can help ease your worries.

The glucose challenge test is a standard screening test across the US that evaluates for gestational diabetes (diabetes in pregnancy). This test is performed between 26-28 weeks, which is typically when diabetes shows up during pregnancy. The first version of this test is given to everyone and is only a screening test to see who needs to go on to take the diagnostic test. 

Why do we test everyone for this?  In the third trimester, weight gain is the name of the game. The placenta sends hormonal signals to your body to support your baby in increasing their birth weight by increasing the calories sent to the baby. This change is why we complete your glucose screening test at this stage in the pregnancy, as your placenta is encouraging the circulation of extra sugar throughout your body while your pancreas is trying to regulate that it is not too much. During this test, you drink a 50mg sugar drink that we will give you and then one hour later, we check your glucose level. If that level comes back high, you must complete an additional test, remember this first one is just the screening test. It tells us whether or not you are at high risk of having diabetes in pregnancy.  The second, diagnostic test then is 100mg sugar drink and we will check your glucose before you drink it and then one, two and three hours after you drink it. This test will determine whether you have diabetes during pregnancy or not. 

Whether or not you have diabetes has a lot to do with your genetics. Your pancreas helps you store the glucose away (out of your blood) while the placenta sends messages to keep the glucose in the blood to support growing the baby. The goal is that this back and forth between the placenta and pancreas evens out nicely, but occasionally the placenta wins, and you may have diabetes. A lot of that is purely based on genetics. But whether you have a genetic history of diabetes in your family or not, you can support your pancreas by eating a healthy diet high in nutrients and protein and low in sugar throughout your pregnancy. 

If you find out that you do have gestational diabetes, we will talk through exactly what that means for you, your baby and your birth. We will set you up with our dietitian in order to give you support and knowledge on how to eat healthy to maintain normal sugar levels. We will also get you set up with supplies, the education and knowledge on how to check your sugar levels and keep a glucose log. Most of the time when diabetes shows up on pregnancy, it goes away after the birth. We will check to verify that as well. However, having it in pregnancy does mean that you have a higher risk of getting it later in life and therefore following those great diet guidelines even after your birth can support your pancreas and lower your risk of having diabetes further down the line.