TL;DR: The pregnancy glucose test is a routine screening for gestational diabetes, usually done between 24 and 28 weeks. Most people start with a one-hour test: you drink a sweet glucose solution, wait an hour, and have your blood drawn. If your number comes back high, you’ll take a longer three-hour test to confirm or rule out gestational diabetes. A high first result is common and doesn’t mean you have diabetes. If you are diagnosed, it’s very manageable with diet changes, monitoring, and sometimes medication.
Have questions about your upcoming glucose screening? Call Lona Sasser Obstetrics and Gynecology at 954-340-1050 or schedule online through ZocDoc.
What Is the Pregnancy Glucose Test?
The pregnancy glucose test checks how well your body processes sugar during pregnancy. Its purpose is to screen for gestational diabetes, a type of diabetes that develops during pregnancy in people who didn’t have diabetes before.
During pregnancy, the placenta makes hormones that help your baby grow. Some of those hormones also make your body more resistant to insulin, the hormone that moves sugar from your blood into your cells. Most bodies make up for this by producing extra insulin. When yours can’t keep up, blood sugar rises, and that’s gestational diabetes.
Gestational diabetes affects somewhere between 6% and 9% of pregnancies in the U.S., and it often causes no noticeable symptoms. That’s why screening is recommended for nearly everyone, not just people who feel unwell.
When Is the Glucose Test Done?
Most people take the pregnancy glucose test between 24 and 28 weeks of pregnancy. This is when insulin resistance usually starts to climb, so the test is more likely to catch a problem.
Your provider may suggest testing earlier, often at your first prenatal visit, if you have risk factors such as:
- Gestational diabetes in a past pregnancy
- A body mass index in the overweight or obese range
- A family history of type 2 diabetes
- Polycystic ovary syndrome (PCOS)
- Having previously given birth to a baby over 9 pounds
- Being of Hispanic, Black, Native American, Asian American, or Pacific Islander heritage
If an early test is normal, you’ll usually be screened again at 24 to 28 weeks. For a broader look at what’s happening at each stage, see our guide to pregnancy symptoms week by week.
The One-Hour Glucose Challenge Test
The first step for most patients is the one-hour glucose challenge test. Here’s how it goes:
- You drink a glucose solution, usually 50 grams of sugar in a small bottle. It tastes like a very sweet, flat soda and is often orange or fruit-punch flavored.
- You’ll be asked to finish it within about five minutes.
- You wait one hour. During that time you’ll need to stay put, avoid eating, and limit activity, since walking around can affect your results.
- Your blood is drawn to measure your blood sugar.
You generally don’t need to fast for the one-hour test, though your provider may ask you to skip sugary foods and drinks beforehand. A result at or above a set cutoff, usually somewhere between 130 and 140 mg/dL depending on the lab, means you’ll need follow-up testing.
If your one-hour result came back high, try not to panic. Many people who need the longer test end up with normal results. Our team can walk you through next steps. Call 954-340-1050 or schedule online through ZocDoc.
The Three-Hour Glucose Tolerance Test
If your one-hour result is above the cutoff, the next step is the three-hour oral glucose tolerance test. This one takes more planning:
- Fast beforehand. You’ll usually need to skip food and drinks other than water for 8 to 14 hours before the test, so most people schedule it first thing in the morning.
- Fasting blood draw. Your blood sugar is checked before you drink anything.
- Stronger drink. You’ll drink a solution with 100 grams of glucose.
- Three more blood draws. Blood is drawn at one, two, and three hours after the drink.
Gestational diabetes is usually diagnosed when two or more of the four readings are at or above the target values. Bring a book or something to keep you busy, and pack a snack for when you’re done. You’ll likely be hungry.
How to Prepare for Your Glucose Test
There’s no way to “study” for the pregnancy glucose test, and you shouldn’t try to game it. The goal is an accurate picture of how your body handles sugar. Still, a few steps can make the day easier:
- Follow your provider’s fasting instructions exactly. These vary between the one-hour and three-hour tests.
- Eat normally in the days before. Cutting carbohydrates drastically before the three-hour test can actually throw off your results.
- Plan your morning. Have the test early, and arrange for someone to drive you if you tend to feel lightheaded.
- Ask about your medications. Some medications can affect blood sugar, so tell your provider what you’re taking.
- Chill the drink if allowed. Many people find it easier to get down cold.
Some people feel nauseated, shaky, or tired after drinking the solution. These effects usually pass quickly. Let the staff know if you feel unwell.
What If You’re Diagnosed With Gestational Diabetes?
Hearing you have gestational diabetes can feel overwhelming, but it’s one of the most manageable pregnancy complications. Most people control it with:
- Nutrition changes. Balanced meals with steady portions of complex carbohydrates, lean protein, and fiber, often with guidance from a dietitian.
- Regular physical activity. Walking after meals can help lower blood sugar.
- Blood sugar monitoring. Checking your levels at home several times a day.
- Medication when needed. Some people need insulin or oral medication to keep levels in range.
Left unmanaged, gestational diabetes can raise the risk of a larger-than-average baby, delivery complications, preeclampsia, and low blood sugar in the newborn. Good management greatly lowers these risks. You’ll also have extra monitoring in late pregnancy, which may include more frequent ultrasounds to track your baby’s growth.
Gestational diabetes usually goes away after delivery. However, it does raise your long-term risk of type 2 diabetes, so you’ll be retested after birth and should keep up with screenings at your annual well-woman exam. The American College of Obstetricians and Gynecologists offers a helpful patient guide if you’d like to read more.
Taking the Next Step With Confidence
The pregnancy glucose test is one of the most common screenings in prenatal care, and for most people it’s simply a box to check. Whether your results come back normal or lead to more testing, catching changes early gives you and your baby the best possible outcome. At Lona Sasser Obstetrics and Gynecology, we guide patients in Coral Springs, FL, and nearby communities through every step of pregnancy, including glucose testing and gestational diabetes care. Call 954-340-1050 or schedule online through ZocDoc to set up your next prenatal visit.
FAQ: Pregnancy Glucose Test
Do I need to fast for the one-hour glucose test?
Usually not. Most providers don’t require fasting for the one-hour glucose challenge test, though they may ask you to avoid sugary foods beforehand. The three-hour test does require fasting, typically for 8 to 14 hours.
What happens if I fail the one-hour glucose test?
You’ll be scheduled for the three-hour glucose tolerance test. A high one-hour result is common, and many people who take the longer test don’t have gestational diabetes.
Can I eat or drink during the glucose test?
No. You’ll need to avoid food and drinks while you wait, though small sips of water are often allowed. Check with your provider first.
Is the glucose drink safe for my baby?
Yes. The amount of sugar is similar to what’s in a large soda or a sweet breakfast, and it’s considered safe during pregnancy.
Does gestational diabetes go away after pregnancy?
In most cases, yes. Blood sugar usually returns to normal after delivery. Because it raises your future risk of type 2 diabetes, you’ll be retested after birth and should keep up with regular screenings.
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