Gestational Diabetes

What Is It?

Gestational diabetes is the appearance of diabetes during pregnancy. Once it occurs, it lasts throughout the remainder of the pregnancy. It affects approximately 7 percent of all pregnant women. Like the other types of diabetes, gestational diabetes results when sugar (glucose) in the bloodstream can't be moved efficiently into body cells, such as muscle cells, that normally use sugar as a body fuel. The hormone insulin helps move sugar from the bloodstream into the cells. In gestational diabetes, the body does not respond well to insulin, unless insulin can be produced or provided in larger amounts. In most women, the disorder goes away when the pregnancy ends, but women who have had gestational diabetes are at increased risk of developing type 2 diabetes later.

Diabetes occurs during pregnancy because certain hormones produced in a pregnancy make the body resistant to insulin's effects. These hormones include cortisol and human placental lactogen. Both of these hormones are essential to a healthy pregnancy and fetus, but each partially blocks the action of insulin. In most women, the pancreas reacts to this situation by producing enough additional insulin to overcome the insulin resistance. In women with gestational diabetes, not enough extra insulin is produced, and sugar can't be processed correctly by the body, so sugar accumulates in the bloodstream.

As the fetus grows larger, larger quantities of the hormones that interfere with insulin are produced. For this reason, gestational diabetes usually starts in the last trimester of pregnancy. At delivery, the body's hormones quickly return to nonpregnant levels. Typically, the pancreas is able to produce enough insulin once again, and blood-glucose levels return to normal.

Symptoms

Some pregnant women with gestational diabetes have the symptoms of diabetes that are associated with high blood glucose (hyperglycemia). These include increased thirst, more frequent urination, weight loss despite increased appetite, fatigue, nausea or vomiting, yeast infections and blurred vision. However, some women have no recognizable symptoms, which is why screening tests for this disease are recommended for almost all pregnant women.

Diagnosis

Gestational diabetes most often is diagnosed during the routine testing that occurs as a part of complete prenatal care. Diabetes is evident if blood sugar levels are high. In order to find gestational diabetes in its earliest form, doctors usually give the pregnant woman a heavily sugared drink prior to testing the blood so that the body's sugar-processing capability is maximally challenged. This is known as an oral glucose-tolerance test.

It is appropriate for a woman who is overweight, has a family history of diabetes, or has symptoms suggesting diabetes to undergo testing at the first prenatal visit. Most other women should be tested 24 to 28 weeks into their pregnancy.