The glucose challenge test is used to screen for gestational diabetes. The test is generally done between weeks 24 and 28 of pregnancy.
However, it can be done as early as your first prenatal visit if you're at high risk of gestational diabetes due to obesity, a personal history of gestational diabetes, a family history of diabetes or other factors. Abnormal test results early in pregnancy might indicate that you have pre-existing type 2 diabetes that wasn't previously recognized — not gestational diabetes.
Most women who have gestational diabetes deliver healthy babies. However, without careful management, gestational diabetes can lead to various pregnancy complications, such as excess fetal growth — which might increase the risk of birth injuries or prompt a C-section delivery.