The Glucose Tolerance Test: What Pregnant Women Need to Know

pregnant woman blood test

If you're pregnant, you're in store for a ton of tests to assess your and your baby's health, but one of the most time-consuming may be the glucose tolerance test. In a nutshell, you chug a syrupy drink, sit around for awhile, then have your blood drawn. You'll want to bring a LOT of magazines ... but you won't want to skip this test.


"The glucose tolerance test determines if a pregnant woman has gestational diabetes," explains Jenny Jaque, an OB/GYN at Health Goes Female. That's diabetes that crops up during pregnancy, and it's incredibly common affecting as many as 18 percent of expectant women.

Gestational diabetes is caused by rising hormone levels, which can dampen your body's ability to metabolize sugar in your bloodstream. If untreated, all that extra sugar will go to your baby, making him overweight and at risk for premature labor. What's more, the disease is often symptomless, so you'd never know you had it ... that is, unless you take the glucose test.

What to Expect:

The test will be scheduled by your healthcare provider sometime between 24 and 28 weeks. You'll be handed a special sugary liquid and told to drink it in five minutes (often the OB/GYN will send you home with a bottle of the stuff and tell you not to drink it until the day of your test, but some practitioners do the whole thing in the office).

What's in the Drink:

"Depending on the flavor the patient chooses, these glucose drinks contain a mixture of corn, dextrose, citric acid, corn flavor, purified water, and the preservatives sodium benzoate and potassium sorbate," says Dr. Jaque. While the Internet is abuzz about the dangers of sodium benzoate and its potential as a carcinogen, the watchdog organization Environmental Working Group has deemed it to be a "low" concern with limited evidence of organ toxicity and not likely to be carcinogenic. The EWG is equally unconcerned about the dangers of potassium sorbate.

In other words, it's fine to imbibe this drink, which Dr. Jaque adds should be refrigerated overnight if you consume it in the morning (plus, it tastes better cold).

What's Next:

An hour after you've slugged it down, they'll draw your blood. A few days later, you'll receive results. If you test positive, that doesn't mean you've definitely got the disease, but it will mean you have to take a more extensive test. 

More from The Stir: How Gestational Diabetes Affects Your Pregnancy & Baby

"A woman will need to fast overnight in preparation for this second test," explains Dr. Jaque. This time, you will get your blood drawn, drink a larger amount of syrupy liquid, then have your blood drawn every hour for the next three hours (so forget magazines and bring a book). This will help your doctor do a more accurate assessment.

If you are diagnosed with gestational diabetes, don't worry -- there's plenty you can do to maintain a healthy pregnancy.

"When a woman tests positive for gestational diabetes, a doctor may recommend certain lifestyle modifications, including scheduled exercise breaks, meal plans, and diabetes medications if needed," says Dr. Jaque. More good news: odds are your condition will disappear once your baby is born and become nothing more than a blip that you should nonetheless be very glad was caught.

What are you most worried will happen health-wise during your pregnancy?

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