What is a Glucose Test During Pregnancy?

What is a Glucose Test During Pregnancy?

Have you heard of gestational diabetes? No problem if it’s a mystery, because we’re here to explain everything you need to know.
Gestational diabetes is a type of diabetes that can develop during pregnancy. It’s relatively common and is usually easy to manage if it’s caught early.

You just need to have a glucose test while you’re pregnant to see if you’re at risk.

Your doctor will usually suggest that you have a glucose test – or a glucose tolerance test, as it’s sometimes called – between week 24 and week 28 (during the second trimester) of your pregnancy.

If you have a family history of diabetes, you’ve had gestational diabetes before, or if you’re obese or over 35 years old, they might want to test you a little earlier – just to be safe.

It’s best not to skip this easy blood test. It’s important both for your health and the health of your peanut. Here, let’s take a look at some of the questions you might have.

In this article 📝

  • Why is a glucose tolerance test during pregnancy important?
  • What should I eat before my one-hour glucose test?
  • How should I prepare for my three-hour glucose test?
  • What if I “fail” my pregnancy glucose test?

Why is a glucose tolerance test during pregnancy important?

A glucose test measures how your body reacts to sugar (or glucose).

If your blood sugar levels are too high, this increases the risk of a few complications, either during your pregnancy or when you deliver your little one.

Your baby might be too big, for instance, which could make their delivery difficult.

Or it could cause your blood pressure to increase suddenly, either while you’re pregnant or after you give birth.

Leaving gestational diabetes untreated also increases the chances of your baby having jaundice or developing type 2 diabetes later in life. And sadly, it adds to the risk of stillbirth.

But if it’s detected early, many of these risks can be avoided by making a few changes to your diet: cutting down on high-sugar foods and refined carbohydrates and getting more greens.

What should I eat before my one-hour glucose test?

There are a couple of types of glucose tests, and preparing for each one is slightly different.

You don’t have to do anything before a one-hour test (this is also known as a two-step test or a screening test).

In the days ahead of your test, and even on the day itself, you can eat and drink as you would normally.

When you arrive at your doctor’s office, you’ll be asked to drink a sweet liquid that tastes a bit like flat orange soda.

An hour later, your blood will be drawn and your blood glucose checked.

How should I prepare for my three-hour glucose test?

The second type of test is called a three-hour glucose test, or a glucose tolerance test. You’ll only need to do this if the results from your first test come back too high.

For this test, you can’t eat or drink anything for eight to 14 hours before your test or during it, other than small sips of water.

You’ll drink a sugary drink once again, but this time you’ll have your blood drawn before you drink it, and three more times every hour afterward.

Set aside three hours for this test, and maybe ask someone to drive you home once you’re done.

Swigging back all that sugar on an empty stomach might make you feel a bit nauseous or light-headed. You should feel better once you have some proper food, though.

What if I “fail” my pregnancy glucose test?

Firstly, don’t panic. You’re doing a great job at getting your little one ready for the world.

It’s much better to know if you have gestational diabetes than not, and with some help, you should be able to make the most important changes quite quickly.

It’s likely that you’ll start to work with a registered dietician to develop a meal plan.

They’ll probably suggest limiting high-sugar foods and refined carbohydrates and eating more lean protein, fruit and veggies, and healthy fats.

Some of these adjustments can be tricky (especially if your pregnancy cravings are yelling for carbs and tasty treats!) but you’ll get there if you seek out healthy alternatives to the things you love.


You might also be told to keep an eye on your glucose levels with a home blood sugar meter. And, if necessary, it’s possible that your doctor will recommend some medication for you.

By going for your scans and taking the right advice at the right time, you should be able to take good care of your blood sugar levels – and, as a result, your baby too.

🤰 Read next:
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Pregnancy Snacks: Healthy Hacks for Pregnancy Cravings
What Are the Best Prenatal Vitamins?
Losing Weight While Pregnant: Should I Worry?
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