What is gestational diabetes?

Gestational diabetes is diabetes mellitus that develops in women for the first time during pregnancy. Some women found to have gestational diabetes actually may have had mild diabetes before pregnancy that was not diagnosed.

Diabetes mellitus (also called “diabetes”) is a condition that causes high levels of glucose in the blood (see the FAQ Diabetes and Women). Glucose is a sugar that is the body’s main source of energy. Health problems can occur when glucose levels are too high.

Gestational diabetes is caused by a change in the way a woman’s body responds to insulin during pregnancy. Insulin is a hormone. It moves glucose out of the blood and into the body’s cells where it can be turned into energy. During pregnancy, a woman’s cells naturally become slightly more resistant to insulin’s effects. This change is designed to increase the mother’s blood glucose level to make more nutrients available to the baby. The mother’s body makes more insulin to keep the blood glucose level normal. In a small number of women, even this increase is not enough to keep their blood glucose levels in the normal range. As a result, they develop gestational diabetes.

All pregnant women are screened for gestational diabetes. You may be asked about your medical history and risk factors or you may have a blood test to measure the level of glucose in your blood. This test usually is done between 24 weeks and 28 weeks of pregnancy. It may be done earlier if you have risk factors.

If I develop gestational diabetes, will I always have diabetes mellitus?
For most women, gestational diabetes goes away after childbirth. However, they remain at high risk of having diabetes later in life. For women who had mild diabetes before pregnancy, it is a lifelong condition.*

*The American College of Obsteticians and Gynecologists