Around the 24th to 28th week of pregnancy, your doctor will likely recommend a glucose challenge test (GCT) to see if you might be developing gestational diabetes, a temporary condition in which insulin fails to break down enough glucose in the blood. The condition affects 2 to 5 percent of all pregnant women. If this test comes back positive, there is an approximately 30 percent chance that you have developed the condition and your doctor would conduct a glucose tolerance test (GTT) [source: Babycenter].
In this test, you are asked to drink a high-sugar liquid and then your blood is collected an hour later so that its sugar level can be measured. In about 15 to 23 percent of women, the blood sugar levels are indeed too high and a follow up three-hour GTT is scheduled, which typically rules out the condition [source: Babycenter].
If you do develop gestational diabetes, your doctor will work with you to develop a diet, exercise and possible insulin-supplementation plan. The condition nearly always ends after the baby is born.