When you’re pregnant, your doctor will recommend a one-hour blood glucose screening and tolerance test to check for gestational diabetes, a type of diabetes that develops during pregnancy. Low-risk pregnant women typically take the screening test between 24 and 28 weeks of pregnancy. Here’s what you need to know.
Why Might I Need to Take the Screening Earlier?
If you’re at increased risk of developing gestational diabetes, your health care provider may recommend earlier screening. Risk factors can include:
- Family history of diabetes
- Gestational diabetes in a previous pregnancy
- Being overweight or obese
- High blood pressure or high cholesterol
- Health conditions associated with insulin problems, such as polycystic ovary syndrome
One-hour Glucose Screening
The screening is intended to show how efficiently your body processes sugar. At your doctor’s office, you’ll receive a sugar solution that contains 50 grams of glucose. The drink tastes like a very sweet slushie (it comes in fruit punch, orange, or lime flavor). It tastes best cold; at Creekside Center, it’s kept chilled. You will need to drink it all within five minutes.
After an hour, a blood sample is taken from your arm to check your blood sugar level. At Creekside Center, the results are usually ready immediately after the test.
What is an abnormal blood glucose level?
Different hospitals and clinics use different standards for determining whether your level is too high. Some practitioners say that if your one-hour blood sugar level is 140 milligrams of glucose per deciliter of blood plasma (mg/dL) or more, you need to have the glucose tolerance test. Others put the cutoff at 130 mg/dL to detect more women who may have gestational diabetes, but false positives are more likely this way. Creekside Center for Women currently has the cutoff at 135 mg/dL.
If your blood glucose level for this screening is higher than 200 mg/dL, most practitioners will consider you diabetic. You won’t need to take the glucose tolerance test.
If the reading shows elevated numbers (between 135 mg/dL and 200 mg/dL), which happens 15% to 23% of the time, you’ll be asked to come back for a three-hour glucose tolerance test to see whether you really do have gestational diabetes.
Tell your doctor if you’re not feeling well or taking any medicine, as these can affect the results of your test. Eat and drink normally in the days leading up to the glucose tolerance test.
Three-Hour Glucose Tolerance Test
For the three-hour test, you will be asked to come to the test fasting, not eating or drinking anything for eight hours. Many women fast overnight and schedule the test first thing in the morning.
After a small blood sample determines your fasting blood sugar level, you’ll drink about eight ounces of a glucose solution containing 3.5 ounces (100 grams) of sugar. Your blood glucose level will be tested again one, two, and three hours after you drink the solution.
You’ll want to bring something to distract you, such as a book or magazine, because you’ll stay seated in the waiting room before the blood draw. Bring something to eat right after your physician takes the final blood sample because you’ll be hungry. After the glucose tolerance test, you can return to your usual activities immediately.
Are there Risks with the Glucose Screening or Tolerance Test?
Obtaining a blood sample has a small risk. You may experience bruising or light bleeding at the site of the blood draw. You also may feel nauseated, dizzy, or lightheaded after drinking the glucose drink.
Do you have questions about the glucose screening or tolerance test? Call us at 479.582.9268 to speak with one of our experienced health care providers. Creekside Center for Women provides women the finest health care in the Northwest Arkansas region.