Clear, evidence-based answers to gestational diabetes test questions, alternatives to the standard test, and linked research.
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Table of Contents
- Is It Necessary to Take the Glucose Test During Pregnancy?
- When Do You Test for Gestational Diabetes?
- What Tests are Done to Diagnose Gestational Diabetes?
- Cut Offs
- Alternatives to the Glucose Test
- Common & Related Questions
- What is the Normal Blood Sugar Level for a Pregnant Woman?
- Can You Brush Your Teeth Before a Glucose Test?
- Can I Drink Water Before Gestational Diabetes Test?
- Can I Drink Water Before My 3 Hour Glucose Test?
- Can You Drink Water After Drinking Glucose Drink?
- What Can I Eat Before My Gestational Diabetes Test?
- How Do I Prepare for My 1 Hour Gestational Diabetes Test?
- What Should I Do Before My 3 Hour Glucose Test?
- Can You Test Gestational Diabetes at Home?
First and foremost, know that it is YOUR choice what happens to your body! You have the option to decline any test or treatment that you don't want, for any reason at all.
This is important to emphasize because patients, and women, are often passive about raising concerns when doctors lead.
Many mothers don't want to take this test, or others, or be induced, but agree after their doctor reiterates it or says it's mandatory/necessary when it's really not.
Know your gut, get informed, and get a second opinion!
Is It Necessary to Take the Glucose Test During Pregnancy?
Testing for gestational diabetes is completely optional, but it is important. Knowing what's happening in your body and how Baby is effected is what your doctor appointments and ultrasounds are all about.
It's important to know if you're having issues with blood sugar because high blood sugar increases the risk of complications during labor and effects Baby after birth. Even mildly high blood sugar (not high enough to be diagnosed as gestational diabetes) is linked to high insulin levels in Baby at birth, larger at birth, and heart defects.
Less expensive third party testing is available if you don't have a doctor or are concerned about insurance.
When Do You Test for Gestational Diabetes?
Testing is normally done between 24-28 weeks of pregnancy.
Insulin resistance is a natural part of pregnancy, and it worsens the further along you are. Research has shown that between 24-28 weeks is the time frame that insulin resistance sort of kicks into high gear.
What Tests are Done to Diagnose Gestational Diabetes?
Gestational diabetes is most commonly diagnosed through the oral glucose tolerance test (OGTT). The OGTT was proposed as a standard screening in 1960; then, the World Health Organization adopted it in 1999. So, the OGTT is a standard test worldwide.
However, standards within the test are different. Depending on the recommending health organization, you'll have different requirements for fasting, drink type, and cut offs.
What is OGTT?
It's a concentrated sugary drink (sugar+water+flavorings+color dyes+more) that the doctor will give you. You can pick from various flavors, but reportedly, the lemon-lime flavor causes less discomfort and tastes better. The study linked says the lemon-lime flavor was made specifically for those reasons, and in my observation of reports from moms, they agree that it's better - but everyone has a preference.
The 1 Hour Test
For this test you will consume the drink within a 10 minute window. The doctor or nurse will prick your finger one hour later to get a blood sugar reading. You should eat before this test.
The 3 Hour Test
This test requires you to fast no less than eight hours, but your doctor will specify a time. The steps are as follows:
- Have blood drawn - a baseline reading; shows how your blood sugar acts normally
- Consume the drink in 10 mins
- Blood drawn one hour later
- Blood drawn one hour later
- Blood drawn one hour later
- (Run to get food!)
- Get the earliest appointment so that the bulk of your fasting time is while you sleep.
- Have a snack and water ready/with you for when you finish because you may feel drained and/or woozy.
You may notice, through talking with other moms, that requirements and cuts offs vary by doctor. The reason for this is that different health organizations around the world have set standards based on different studies. Each organization works at their own pace, and it takes time to publish new policy. Because the majority of this audience is from the United States, the information below is from American organizations.
What is the Normal Range for Gestational Diabetes Test?
- Fasting/morning blood sugar should read no higher than 94.
- 1 hour after glucose drink should read no higher than 179.
- 2 hours after glucose drink should read no higher than 154.
This and other international information can be found in this report.
The American Congress of Obstetricians & Gynecologists (ACOG)
ACOG recommends a two-step procedure:
- 50 gram OGTT (no fast)
- Test blood 1 hour later.
- No diagnosis if reading is 139 or less.
- If reading is 140 or more, proceed to 3 hour test.
- If reading is 200 or more, diagnosed.
- 100 gram OGTT (at least an 8 hour fast)
- Fasting reading should be 94 or less
- 1 hour reading should be 179 or less
- 2 hour reading should be 154 or less
- 3 hour reading should be 139 or less
- If any two readings are above range, diagnosed.
The International Association of Diabetes and Pregnancy Study Group (IADPSG)
- 1st trimester A1c or plasma testing (doctor will specify fasting or not, no OGTT)
- If reading is 92 or more, diagnosed.
- If reading is 91 or less, test with 75 gram OGTT at 24-28 weeks.
- 75 gram OGTT (fasting)
- Fasting reading should be 91 or less.
- 1 hour reading should be 179 or less.
- 2 hour reading should be 152 or less.
- If any ONE of these is exceeded, diagnosed.
- 75 gram OGTT (fasting)
The American Diabetes Association (ADA)
The ADA's criteria are the same as the IADPSG's above.
It is said the the ADA's/IADPSG's criteria is excessive and "results in over diagnosis with unnecessary interventions," but the 1st trimester testing gives the ability to detect and treat early.
Alternatives to the Glucose Test
If you have reservations about the OGTT, for any reason, talk to your doctor about alternatives. Remember; YOU decide what you put into your body and what happens to it. Your doctor should listen to your concerns and suggest common ground between the two of you. But please don't skip testing because Baby's health is at risk.
"As women, many of us were taught to “be nice,” or “be seen and not heard.” As patients, this can translate into accepting tests, procedures, and treatments that we feel we don’t want or need, or that, in this case, might not be safe for us or our babies! "https://avivaromm.com/dont-drink-glucola-gestational-diabetes/
Reasons to Choose an Alternative
- Moms report side effects like headaches, nausea, vomiting, diarrhea, etc.
- One mom still experiencing pregnancy nausea said she couldn't finish the drink in time, threw up what she got down, and had to try again a different day.
- The drinks contain toxins that are:
- categorized as flame retardants.
- known to interfere with thyroid function.
- leave residue in organs.
- and more.
- The drinks contains dyes known to be harmful.
- You have to finish the drink within 10 minutes. It may sound like an easy task, but if you don't like the taste, it's much harder than you think.
1st Trimester Testing
Some doctors have started to test for gestational diabetes early when the mom has a combination of risk factors or if she had gestational diabetes before.
Even if you have no risk factors (like 44% of women diagnosed), it's a great idea to test in the 1st trimester. At your appointment, tell your doctor you want to have an A1c test because testing in the first trimester is over 95% accurate in predicting a gestational diabetes diagnosis later in pregnancy. Hopefully, there won't be any push back because your doctor only has to "check that box" when ordering the rest of your blood work. You won't notice any difference because this test requires nothing extra of you.
In fact, based on the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study, the International Association of Diabetes and Pregnancy Study Group (IADPSG) and American Diabetes Association (ADA) RECOMMEND testing fasting plasma glucose, HbA1c or random plasma glucose IN ALL WOMEN at the first prenatal visit.
Please direct your doctor to the site below if they are unaware.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4866200/
If your A1c reading is 92 or above, you'll be diagnosed then and won't have to test at 24-28 weeks. Yes; that means you'll have to deal with gestational diabetes longer, but it also means Baby will have better care earlier on.
If your reading is 91 or below, you'll be retested by OGTT or alternative method at 24-28 (when insulin resistance begins to worsen).
Jelly beans are more appealing than the drink because they're tastier and have less side effects. You just have to consume the same amount of grams of sugar that the drink has and it's considered to have the same effect.
Other Foods or Drinks
Same concept here. You and your doctor can discuss a meal or drink that equals the sugar amount of the drink.
Food Log & Self Monitoring
In this case you would get a blood glucose meter and take it home. For a specified period, maybe 1-2 weeks, you'll log your food and test your blood sugar four times a day, just as you would do if you were diagnosed with gestational diabetes.
The doctor will study your readings and determine diagnosis.
Common & Related Questions
What is the Normal Blood Sugar Level for a Pregnant Woman?
These are average blood sugars for "healthy weight pregnant women without gestational diabetes:"
- Fasting/morning - 71
- 1 hour after meal - 109
- 2 hours after meal - 99
Can You Brush Your Teeth Before a Glucose Test?
Can I Drink Water Before Gestational Diabetes Test?
Your doctor will tell you. It depends on the kind of test - a fasting test doesn't allow water but the 1 hour non-fasting test does.
Can I Drink Water Before My 3 Hour Glucose Test?
No. The 3 hour test is a fasting test and that includes fasting from water.
Can You Drink Water After Drinking Glucose Drink?
You cannot drink or eat anything after drinking the glucola drink until all of your tests are complete. If you're taking the 1 hour test, you can drink after your finger is pricked. If you're taking the 2 or 3 hour test, you can drink after the last blood draw.
What Can I Eat Before My Gestational Diabetes Test?
If this is the 1 hour non-fasting test, you can eat whatever you like. It's best to eat what you normally eat so that your test results are more accurate. Ideally, you'd eat a piece of protein with veggies and a small side of carbs.
If this is a 2 or 3 hour test, you must fast. For your last meal before the fast begins, it's best to eat what you normally eat so that your test results are more accurate. Ideally, you'd eat a piece of protein with veggies and a small side of carbs.
How Do I Prepare for My 1 Hour Gestational Diabetes Test?
Make sure you've eaten in the past 2-3 hours. No other preparation is necessary.
What Should I Do Before My 3 Hour Glucose Test?
Since this is a fasting test, hopefully it's early in the morning so that you don't have to be awake and hungry for long. There's nothing that you should do. Just make sure you don't eat or drink, not even water.
Can You Test Gestational Diabetes at Home?
You can get a glucose monitor from any grocery or drug store and test your blood sugar at home. See the
Food Log & Self Monitoring.
Even though the standard test for gestational diabetes is unappealing, it's important! High blood sugars, even slightly high, program Baby's DNA and insulin production, predisposing him/her to childhood diabetes. High blood sugars also put Baby at higher risk for serious labor complications.
There are many alternatives to the standard test and your doctor should be open to at least one of them. Your doctor should also respect your concerns and decisions. If not, inexpensive third party testing is available.