Ok, you’ve failed (or thought about failing) your 1-hour glucose test? What happens now? There are a couple of ways it could go (including taking the longer 3-hour glucose drink), but mostly I’m glad you’re here wondering what will happen. Taking this seriously is one of the smartest things you can do in your pregnancy — so let me give you the next steps!
But, how do I know so much about the stupid glucose test (I really do hate it and I really feel for people who also hate it)? Hi — I’m Hilary, The Pregnancy Nurse. I’ve been a nurse since 1997 and I’ve worked in labor and delivery for 20 years. I’ve also spent some time subbing into a diabetic clinic where I learned quite a bit about what people should expect, so I think I’m an expert for you on this one. Oh, and I failed the glucose test a number of times. It absolutely sucked. So I get. you!
What happens if/when you fail your 1-hour glucose screening?
There are two options.
For most people, they will recommend the 3-hour oral glucose tolerance test (sometimes called glucose screening test, or a glucose challenge test or OGTT). We’ll talk more about that in a bit.
For some people, who fail it by a lot they will just diagnose you with gestational diabetes mellitus (GDM). That means you’ll then visit a dietician and come up with a way to control this with diet. If that doesn’t work they will then work on medications (most often oral, although some people will need insulin now and then) to help control it. You’re just basically skipping the 3-hour test because you will most likely fail it.
Pro Tip: most of this info is from the United States. I have heard of other countries that just start with a 2-hour test, but in the US the standard of care is to offer the 1- hour test and then if you fail that, do the 3-hour test.
What’s the Three-Hour Glucose Test?
It’s a lot like the first test, but it’s 3 hours (2 hours longer)
I believe all providers want a fasting glucose, which means you’ll want to do this test early in the morning as you won’t be able to eat until you’re done.
They will take your blood glucose upon arrival (checking your fasting blood glucose level), and then will have you drink a more sugary glucose solution than last time (it has more sugar in it than before). You’ll then have a blood draw a one hour, two hours and a final one at 3 hours.
Then you’ll want a nice snack that balance carbs and proteins. I always did a PB&J sandwich as it had some proein with the peanut butter, and lots of carbs to help carry you through until you get home and have an actual meal.
It is REALLY important that you not eat or drink anything during the test. Some places will allow small sips of water, but if you were to eat during the test it will nullify the results and you’ll have to start over.
The lab will test these blood samples for the glucose level in your blood as insulin kicks in. The hope is that your blood glucose levels go down nicely as time goes by. The test result is normally reported by the next day (although it varies on when you will get the information).
Fun fact: You can fail one of the 3-hour tests and still not be diagnosed with GDM, just failing one in the 3-hour glucose challenge test isn’t enough to diagnose you.
If you’re at the spot where you’re taking the glucose test it’s JUST the right time to also get started on your birth class. I recommend this one. It’s taught by an expert, doesn’t take long and I love the price points!
What if I fail the 3-hour glucose test?
Valid question, but I want to be really clear that just because you failed the 1-hour does NOT mean you’ll likely fail the 3-hour.
As far as I can tell, about 25% of the people fail the 1-hour glucose test, and only 2-10% of people are ultimately diagnosed with gestational diabetes. So this isn’t a time to catastrophize and worry about what life will be like diabetic. Let’s just take each step at a time.
BUT, if you ultimately fail the 3-hour test you’ll be diagnosed with gestational diabetes.
They will encourage you to check your blood sugar in the mornings and after every meal. If those numbers continue to be high, even when you’re eating the proper diet, they may recommend medication like metformin or possibly insulin depending on how off the numbers are. If your blood sugar are in the in the normal range, they will encourage you to continue the diet they recommended (usually a certain # of grams of carbs in each meal, balanced with protein).
The VAST majority of people who have gestational diabetes control it with diet alone, and don’t need insulin shots or even oral meds.
Pro Tip: SO many people think they were mis-diagnosed with GDM because their levels remain very stable on the diet. But GDM could progress quickly as you progress in your pregnancy so it’s really important you keep an eye on it. The glucose test are just our best way to check for who’s at risk.
I would give a plug here to see a dietician to learn about how to best eat if you are diagnosed with gestational diabetes. Many providers try to handle it on their own, but a dietician visit would be the gold standard of care. Often these can even be done remotely. Even if your doctor wants to “handle” it on their own, you could ask them if there’s someone you could see to really dial in your diet.
OR you could just use the glucose monitor, and see how your sugars are. The big hope is that your sugars will remain in the suggested guidelines and with small modifications you’ll have a term, healthy pregnancy.
I recommend a dietician because they can really help you with some life-long guidelines to help your eating habits. Dieticians are an under-used resource!
Is there an alternate test?
Man, I wish. There are various reasons why they have to do this test this way…. which really stinks because I agree it’s HORRIBLE. I FEEL horrible after it and it frankly isn’t awesome for our bodies. But, because it’s a one-time test and it can tell if we’re going to have issues further down the road.
If you absolutely don’t want to take the 3-hour test talk with your provider. Some recommend taking your blood sugar a few times/day for a few weeks to see what the results are. Many people would prefer that to the 3-hour test, so see what works for you after discussing it with your provider.
Unfortunately, the only one studied well is doing the 3-hour test as it is now.
What else happens?
You may have an extra anatomy ultrasound, BPP’s and NST’s. I would recommend taking my free prenatal class to learn more about these tests.
BUT if you’re diabetic there are good chances of more interventions with your pregnancy, or at least being offered them (like being induced early). It’s really important you know how to talk with your team to get the information you need to make choices as you head towards to your due date. The Online Prenatal Class for Couples is the easy way to get prepared for all of that. You’ll feel so much more prepared and confident for what you might face (it includes that information on testing you might have done too).
I know a lot of people take a diagnosis of gestational diabetes as a death sentence, but the vast majority of people resume their regular eating patterns after they have the baby. It doesn’t mean that you shouldn’t watch your blood sugars and how you eat afterwards.
If you have gestational diabetes you do have a higher risk of having diabetes as you get older. Being pregnant puts similar strain on your cells as getting older, and this can be a map of what to expect as you age. So, take it seriously, but also be aware that life is going to go on.
Some people may be diagnosed with type 2 diabetes after pregnancy if sugar levels continue to be abnormal. Most often they recommend a 2-hour glucose tolerance test 6-12 weeks after delivery to see if you have lingering blood sugar level issues.
I really did want to give you a pat on the back for taking this test during pregnancy. SO many people just stick their head in the sand or say the test has too many preservatives so they don’t want to take it. but undiagnosed diabetes in pregnant women does puts you at risk for severe complications for you and baby including stillbirth. So I’m so glad you’re taking your recommend tests between 24 and 28 weeks of pregnancy.
And, like I said — if you’re at the point where you’re taking these tests you’re at the PERFECT spot to get your prenatal class in. Studies show it reduces your chance of a C-section or other interventions at birth so come join me in here.
And, if you’re not quite sure you’re ready for that whole thing, check out the free lesson from it. It’s your first step toward getting in the driver’s seat of your birth.
This is just a part of my series on The Pregnancy Glucose Test For Gestational Diabetes << be sure to read that post for ALL the info on that important test!
- About the Author
- Latest Posts
A nurse since 1997, she has worked in various fields including pediatrics, geriatrics & hospice. She has 20 years of labor and delivery experience in the San Jose, CA and Phoenix, AZ areas.
As an evidence-based prenatal educator Hilary has delivered thousands of babies and has educated hundreds of thousands of parents from a diverse patient population to help them have a confident birth.