Gestational Diabetes

Gestational diabetes is also called gestational diabetes mellitus, or GDM for short. This occurs during pregnancy in some women. Gestational diabetes develops in about seven percent of women who are pregnant. It usually begins around the sixth month of pregnancy. In most women, it ends when the pregnancy is over. However, once you've had gestational diabetes, your chances are between one and two out of three that you will have it again the next time you are pregnant.

Women who have gestational diabetes have plenty of insulin. But the effect of that insulin is blocked in part by their body's cells, which have developed insulin resistance. That means the cells can't use the insulin the way they need to, so glucose becomes elevated in the blood.


Hormones found in the pregnant woman cause insulin resistance during pregnancy. The placenta brings nutrients and water from the mother's bloodstream to the growing baby. At 20 to 24 weeks into the pregnancy, these hormones may begin to block the normal action of insulin. In most women, the pancreas makes more insulin to overcome this effect. But in some women, the pancreas can't make enough insulin to work against the insulin resistance. In those cases, the woman develops gestational diabetes.

Women who have gestational diabetes are at higher risk of developing type 2 diabetes later in life. However, in most cases of gestational diabetes, your glucose levels return to normal once your baby is born. Six weeks or so after the birth, your doctor will check to see if your glucose levels are normal. If they are, you should be retested at least once every three years.

If your glucose levels are abnormal, your doctor may suggest that you see a registered dietitian to help you make some changes to your diet. It is key that you focus on maintaining your weight within the range recommended for your height. You may also need to start taking medicine to control your blood glucose levels.

Being physically active and eating right can help to control your weight and reduce your risk of developing diabetes in the future. Make these new lifestyle habits part or your daily routine.

If you become pregnant again - or even if you are just starting to think about getting pregnant - be sure to see your doctor as soon as possible. That way, he or she can begin checking you early for the return of gestational diabetes.

Causes of Gestational Diabetes

Heredity and environmental factors work together to cause gestational diabetes.



You are more likely to develop gestational diabetes while you are pregnant if you have close relatives with diabetes, especially on your mother's side. You are also at increased risk if you are Hispanic or Latino, African-American, Asian-American, Native American or a Pacific Islander.



Some of the environmental triggers for gestational diabetes include:

  • Being Overweight. If you are overweight before becoming pregnant, you are more at risk for developing gestational diabetes.
  • Your Age. Gestational diabetes is more common in women older than age 25.