Glucose Test

A glucose screening test during pregnancy, also known as a glucose challenge or tolerance test, screens for gestational diabetes, a condition that can cause harm to you or your baby if not properly managed.

Gestational diabetes occurs when your blood sugar is too high during pregnancy. As your body changes, hormonally and physically, while carrying a baby, you begin to use insulin less effectively, resulting in higher blood sugar levels.

Some increase in glucose levels is expected during this time; however, if they rise too much, your pregnancy is at a greater risk for complications.

Why is a glucose tolerance test performed?

A glucose test helps detect gestational diabetes.

The American College of Obstetricians and Gynecologists recommends all women with pregnancies have a glucose test. It’s generally performed between 24 and 28 weeks of pregnancy.

While certain conditions do increase your risk of developing gestational diabetes, it can happen during any pregnancy. Roughly 7% of expectant mothers will develop gestational diabetes during their pregnancy.

Factors that increase your chances of gestational diabetes include:

• Having diabetes during a previous pregnancy
• Family history of diabetes
• Obesity
• Certain medical conditions, such as polycystic ovarian syndrome or metabolic syndrome

Sometimes if you have these risk factors, a glucose test might be recommended earlier than 24 weeks.

Why is it important to diagnose and manage gestational diabetes?

Because gestational diabetes can cause many issues later in pregnancy, it’s important to work with your doctor to diagnose it and manage it through healthy eating habits, glucose monitoring and medication.

You might even be referred to a high-risk specialist, like the ones at our Maternal Fetal Medicine program, to monitor the rest of your pregnancy.

Learn more about our diabetics in pregnancy program

Diagnosing and managing gestational diabetes can help you avoid such issues as:

• High blood pressure, or preeclampsia, during pregnancy, which can decrease blood flow to the placenta
• Premature birth
• Caesarean section due to a larger baby
• Increased risk of developing type 2 diabetes or hypertension later in life

Although blood sugar typically returns to normal after the birth, you or your baby might have lingering effects and both of you could be at higher risk for diabetes as you get older.

Risks of a glucose test

There are no known risks to a glucose challenge test.

What happens during a glucose test?

This is a simple, routine test.

First, you’ll drink a sugary liquid provided by us and we’ll ask that you do not eat or drink anything else (including chewing gum) for an hour. Then, we’ll draw your blood to check your sugar level.

If it’s too high, you may be asked to complete a 3-hour glucose test, which requires fasting for 8-12 hours before the test. You’ll again be asked to drink the glucose solution and your blood will be drawn four times over three hours. This test can confirm if you have gestational diabetes or not.

Results of a glucose challenge test

Results from the blood test should be available within a few days.

Typically, a normal blood glucose level after drinking the liquid is lower than 140 mg/dL.

One abnormal result typically is not enough to diagnose gestational diabetes so you shouldn’t worry if your first result is higher than the normal range.

If during your second test, blood sugar levels remain high over several of the blood draws, you’ll be diagnosed with gestational diabetes.

It’s important to remember the condition is very manageable with changes to your diet and physical activity. Medication can be used if needed.

You will need to monitor your levels at home for the duration of your pregnancy.

Specialists in our Maternal Fetal Medicine program are uniquely trained to help you manage gestational diabetes to ensure your baby arrives safely and you remain healthy throughout the rest of your pregnancy.