What Is A Glucose Test & How Should You Prepare For It?

If you’re in your second trimester, you may have heard about an upcoming glucose test. Many women receive a glucose test towards the end of their second trimester or the start of the third, and it’s designed to measure blood sugar levels and assess your risk for gestational diabetes.

We know that the word “diabetes” can come as a bit of a shock, especially if you don’t have a history of blood sugar issues. But Gestational Diabetes is quite common, as it’s seen in up to 10% of pregnancies in the US. What’s more, you don’t need to have diabetes before pregnancy to develop it.

Hormonal changes cause our bodies to use insulin less effectively while requiring more of it during pregnancy — and this is called insulin resistance. All women in the later stages of pregnancy will experience this, but to varying degrees depending on their pre-pregnancy health.

Luckily, this condition is easily manageable in most cases. But since it is often symptom-free, glucose tests to screen for gestational diabetes will be a routine part of your prenatal tests. There are a few types of tests that doctors use to evaluate how your body is processing sugars, and it can be a simple and effective way to catch potential issues before they cause more problems. 

So, what is a glucose test? 

A glucose test measures the level of sugar in your blood to determine your risk of gestational diabetes or if you currently have it. In most cases, you’ll have this scheduled around 24-28 weeks of pregnancy, however, you could be scheduled for one earlier if you’re at an increased risk for developing gestational diabetes.

What increases your risk of gestational diabetes?

Gestational diabetes can affect anyone during pregnancy, but you’re more likely to develop it if you’re over 25 and have had it in a previous pregnancy. Certain conditions can also increase your risk such as being overweight and sedentary, or if you currently have high blood sugar, high blood pressure, or PCOS (learn more about this here!).

These factors might increase your risk of developing gestational diabetes, but it’s definitely not a guarantee that you will. Women that are seemingly healthy can develop gestational diabetes, which is why it’s part of your regular screenings. Now, let’s learn about what you can expect from this testing process …

Glucose Challenge Screening Test

This preliminary test is often used as the first point of testing for gestational diabetes and you’ll often hear it referred to as the “1-hour test” or “two-step test”. You won’t need to do anything to prepare for this like change your diet, because when you go in, you’ll be given a sweetened liquid to drink and then need to wait approximately 1 hour before having your blood drawn (blood sugar levels tend to peak within this time). This will tell doctors how effectively your body is processing sugar. If blood sugar levels are higher-than-normal or there are any other concerns, your doctor may order a glucose tolerance test.

Glucose Tolerance Test

If your blood sugar is looking a little high, your doctor might order another test to learn about your blood sugar levels after fasting. With this test, you’ll be instructed to drink a sugary liquid similar to the first test, but your blood will be drawn first as a baseline, then once every hour for 3 hours after drinking the liquid. 

How to prepare for the test

You’ll need to eat a balanced diet with some of your favorite nutrient-dense carbohydrates like whole-wheat pasta, potatoes, fruits, and veggies 3 days before the test. You’ll need to get at least 150g of carbs in the day before your test, which should be easily attainable through a normal diet.

You’ll be instructed to avoid any food or drinks (besides sips of water) for 14 hours before the test, so it’s a good idea to schedule it first thing in the morning. Plan to get a ride to and from your appointment as with any fasting blood test, there’s the small possibility you might feel lightheaded or queasy afterwards.

If you have any dietary concerns or sensitivities to carbohydrates or any of the steps prior to the test, your doctor should be able to help! 

Can false-negatives or false-positives happen?

As with almost all tests, there is a small, but unfortunate, chance of a misdiagnosis with a false-positive or negative result of a glucose test. However, your blood test results should be verified by a follow-up glucose tolerance test and this should help paint a clearer picture of your blood sugar health. If you have any concerns or questions about your diagnosis or test results, we encourage you to bring them up to your doctor and get further testing if needed.

What do my results mean? 

If your test results come back abnormal or slightly elevated, your doctor may suggest dietary changes or another glucose test later on in pregnancy. Two or more positive glucose tests may lead to a diagnosis of gestational diabetes or another blood sugar issue. Your doctor will be able to help advise on a treatment plan to help you better manage it (you can find out tips on managing your blood sugar here!).

Does this mean I’ll have diabetes after pregnancy?

With proper management, your blood sugar will likely return to pre-pregnancy levels within the first few months after birth. However, that doesn’t mean you’re completely in the clear of developing diabetes later on. It’s estimated that half of women with gestational diabetes develop type 2 diabetes later on, but there are things you can do to help manage this risk.

Research shows that the year following birth is really important to your long-term health, as you can reduce your risk of future diabetes after birth by staying active and reducing excess baby weight. There’s a lot of pressure on women these days to “bounce back” from pregnancy, but that should not be the message. The first year of birth is all about helping your body recover from pregnancy and rebuild a healthy baseline to help you live the life you want. Learn more about why the first year after birth is so important in here!

Your doctor will likely recommend having your blood sugar tested within the first few months after giving birth and then monitoring them for 1 to 3 years following.

On the Baby2Body app, we help you develop healthy lifestyle habits before, during, and after pregnancy, with meal plans, personalized workouts, and daily healthy living tips. If you’re not already on Baby2Body, be sure to download the app today!

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