About 7 percent of pregnant women develop abnormalities in their insulin production and blood glucose levels and are considered to have "gestational diabetes." The condition can usually be managed through meal planning and physical activity, and when it is well controlled, the baby will be healthy. Although these women's glucose and insulin levels often return to normal after pregnancy, as many as 50 percent may develop type 2 diabetes within 20 years of the pregnancy.
The following topics answer key questions about gestational diabetes:
- What causes gestational diabetes?
- Who gets gestational diabetes?
- How is gestational diabetes diagnosed?
- How is gestational diabetes treated?
- Will I need to take drugs?
- What will happen to me and my baby after I give birth?
- Where can I find out more about gestational diabetes?
As the pregnancy progresses, the placenta secretes hormones that make it harder for a woman's body to use insulin normally, to turn glucose in the blood into fuel for the cells. Thus, the mother needs an increasingly large amount of insulin to maintain normal blood glucose levels. When the mother's pancreas can't keep up with the higher demand for insulin, the body falls behind in processing glucose, and gestational diabetes results.
If not controlled, the excess glucose in the blood can pass into the baby's blood; the baby matches the increase in glucose by ramping up its own insulin production, and the energy is stored as fat. Large babies can lead to difficult deliveries. In addition, the baby's overproduction of insulin may increase his or her eventual risk of obesity and type 2 diabetes.
Gestational diabetes can occur in any pregnant woman, but there are certain risk factors that make it more likely:
- A woman is overweight.
- She is over 30.
- She has a strong family history of diabetes.
- She had gestational diabetes in a previous pregnancy.
- She previously had a baby weighing more than 9 pounds at birth.
- She has polycystic ovary syndrome.
- She has glycosuria, or glucose in the urine.
- She has impaired fasting glucose or impaired glucose tolerance. These conditions are characterized by elevated levels of blood glucose, the first after fasting and the second after consuming a high-glucose drink.
- She is black, Hispanic, Asian, American Indian, or a Pacific Islander.
The routine test used to diagnose gestational diabetes is called a glucose challenge. The woman consumes a drink with 50 grams of glucose; an hour later, her blood is tested to see how well the body has processed that glucose. If her blood glucose level is 140 milligrams/deciliter or more, the doctor will prescribe a second test, known as a glucose tolerance test, to confirm the diagnosis.
After a fast of eight to 12 hours, the woman drinks a liquid with 100 grams of glucose. Then her blood is tested four times, once at baseline and then again each hour for three hours. Two abnormal readings indicate gestational diabetes; one suggests the woman should be screened again in a month.
Pregnant women at very low risk for gestational diabetes—that is, those who are a member of an ethnic group that has a low prevalence of diabetes, are younger than 25, of normal weight before becoming pregnant, with no close family history of diabetes and no history of abnormal glucose tolerance or troublesome pregnancies—might not be screened at all. Women who are neither at high or low risk should be screened between 24 and 28 weeks into pregnancy. Women at high risk might be screened earlier, although it is not always possible to detect gestational diabetes much before 24 weeks.
The goal of treatment is to keep blood glucose levels measured after a fast at less than or equal to 95 mg/dl, and blood glucose an hour after eating at less than or equal to 140 mg/dl. Usually, that can be accomplished through careful meal planning and through exercise. A dietitian can help formulate a meal plan that takes into account both the ingredients and the timing of meals. Because a growing fetus is constantly feeding, it's important to spread out meals and snacks to provide a consistent flow of nutrients.
Carbohydrate tends to have the greatest effect on blood glucose. The balance between the amount of carbohydrate eaten and the available insulin in the bloodstream determines how much your blood glucose level goes up after meals or snacks. To help control your blood glucose, you need to know what foods contain carbohydrate, the size of a "serving" of different foods, and how many carbohydrate servings to eat each day. There's no magic number of daily servings that's right for everyone; instead, it is important to work with a dietitian to determine what will work for you. In addition, women with gestational diabetes need to make sure they don't cut carbohydrate and calories so much that the body switches from using carbs for energy to using fat. Ketones, the byproducts of burning fat, may hurt the baby.
Regular physical activity, like a brisk walk, can also help keep blood glucose at the right levels.
Some women will not be able to control their blood glucose through a meal plan and physical activity alone and will need to monitor their glucose levels and possibly take insulin injections.
Once the baby and placenta are delivered, the effect of the placental hormones is removed. This usually puts an end to gestational diabetes. The mother should be checked six to eight weeks postpartum with a two-hour 75-g oral glucose tolerance test to be sure she no longer has diabetes. Women who have had gestational diabetes may develop diabetes in the future, so it's important for them to maintain a healthy lifestyle and to keep their weight under control. They're also likely to develop gestational diabetes in subsequent pregnancies; this risk can be lowered by losing weight, eating healthfully, and being physically active.
A baby born to a woman with gestational diabetes may initially experience abnormal blood sugar levels, even if the disease was well controlled during pregnancy, so doctors will test the baby's blood and give insulin when needed. This is a temporary condition.
More information on pediatric asthma is available at these websites recommended by the U.S. News & World Report library:
The American Diabetes Association's Gestational Diabetes Resource Guide
Helps women to better understand what causes gestational diabetes and how to manage it during pregnancy through birth, and beyond
MedlinePlus Medical Encyclopedia: Gestational Diabetes
Hyperlinks to other entries within the encyclopedia help visitors to better understand symptoms, tests, treatments, and long-term risk reductions of gestational diabetes
What I Need to Know About Gestational Diabetes, from the National Diabetes Information Clearinghouse
Explains the causes of gestational diabetes, as in a well-packaged primer
Gestational Diabetes: What It Means for Me and My Baby
A service of the American Academy of Family Physicians, this fact sheet provides a basic understanding of what causes gestational diabetes and how to manage it for a healthy pregnancy and healthy baby
Last reviewed on 10/27/08
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