Pregnancy Information Center

Information, Symptoms, Treatments and Resources


Your Guide to Prenatal Tests

Glucose Test

Glucose Test

When it’s done: Between weeks 24 and 28

In the second trimester, you’re at risk for gestational diabetes, a type of diabetes that develops in pregnancy. To screen for it, you’ll quickly drink 50 grams of a special sugary beverage. One hour later, your blood glucose level will be checked. If the results indicate gestational diabetes, you’ll need a follow-up oral glucose tolerance test (OGTT) before a diagnosis can be made. 

Gestational diabetes can result in an overly large baby, a C-section or early labor, among other risks. However, with proper care, these risks can usually be avoided.

By Jenilee Matz, MPH. Published on May 6, 2013. Jenilee is a medical writer, health educator and triathlete based in Charlotte, NC. Updated on December 30, 2015.
Reviewed by Elisabeth Aron, MD, MPH, FACOG on September 27, 2015.