Gestational diabetes is high blood sugar (diabetes) that starts or is first diagnosed during pregnancy.
Glucose intolerance during pregnancy
Causes, incidence, and risk factors
Pregnancy hormones can block insulin from doing its job. When this happens, glucose levels may increase in a pregnant woman's blood.
You are at greater risk for gestational diabetes if you:
- Are older than 25 when you are pregnant
- Have a family history of diabetes
- Gave birth to a baby that weighed more than 9 pounds or had a birth defect
- Have sugar (glucose) in your urine when you see your doctor for a regular prenatal visit
- Have high blood pressure
- Have too much amniotic fluid
- Have had an unexplained miscarriage or stillbirth
- Were overweight before your pregnancy
Usually there are no symptoms, or the symptoms are mild and not life threatening to the pregnant woman. Often, the blood sugar (glucose) level returns to normal after delivery.
Symptoms may include:
Signs and tests
Gestational diabetes usually starts halfway through the pregnancy. All pregnant women should receive an oral glucose tolerance test between the 24th and 28th week of pregnancy to screen for the condition. Women who have risk factors for gestational diabetes may have this test earlier in the pregnancy.
Once you are diagnosed with gestational diabetes, you can see how well you are doing by testing your glucose level at home. The most common way involves pricking your finger and putting a drop of your blood on a machine that will give you a glucose reading.
The goals of treatment are to keep blood sugar (glucose) levels within normal limits during the pregnancy, and to make sure that the growing baby is healthy.
WATCHING YOUR BABY
Your health care provider should closely check both you and your baby throughout the pregnancy. Fetal monitoring to check the size and health of the fetus often includes ultrasound and nonstress tests.
- A nonstress test is a very simple, painless test for you and your baby. A machine that hears and displays your baby's heartbeat (electronic fetal monitor) is placed on your abdomen. When the baby moves, the baby's heart rate normally increases 15 - 20 beats above its regular rate.
- Your health care provider can compare the pattern of your baby's heartbeat to movements and find out whether the baby is doing well. The health care provider will look for increases in the baby's normal heart rate occurring within a certain period of time.
DIET AND EXERCISE
The best way to improve your diet is by eating a variety of healthy foods. You should learn how to read food labels, and check them when making food decisions. Talk to your doctor or dietitian if you are a vegetarian or on some other special diet.
In general, your diet should be moderate in fat and protein and provide controlled levels of carbohydrates through foods that include fruits, vegetables, and complex carbohydrates (such as bread, cereal, pasta, and rice). You will also be asked to cut back on foods that contain a lot of sugar, such as soft drinks, fruit juices, and pastries.
You will be asked to eat three small- to moderate-sized meals and one or more snacks each day. Do not skip meals and snacks. Keep the amount and types of food (carbohydrates, fats, and proteins) the same from day to day.
- Your doctor or nurse will prescribe a daily prenatal vitamin. They may suggest that you take extra iron or calcium. Talk to your doctor or nurse if you're a vegetarian or are on some other special diet.
- Remember that "eating for two" does not mean you need to eat twice as many calories. You usually need just 300 extra calories a day (such as a glass of milk, a banana, and 10 crackers).
For details on what you should eat, see: Diabetes diet - gestational
If managing your diet does not control blood sugar (glucose) levels, you may be prescribed diabetes medicine by mouth or insulin therapy. You will need to monitor your blood sugar (glucose) levels during treatment.
Most women who develop gestational diabetes will not need diabetes medicines or insulin, but some will.
Most women with gestational diabetes are able to control their blood sugar and avoid harm to themselves or their baby.
Pregnant women with gestational diabetes tend to have larger babies at birth. This can increase the chance of problems at the time of delivery, including:
- Birth injury (trauma) because of the baby's large size
- Delivery by c-section
Your baby is more likely to have periods of low blood sugar (hypoglycemia) during the first few days of life.
Mothers with gestational diabetes have an increased risk for high blood pressure during pregnancy.
There is a slightly increased risk of the baby dying when the mother has untreated gestational diabetes. Controlling blood sugar levels reduces this risk.
High blood sugar (glucose) levels often go back to normal after delivery. However, women with gestational diabetes should be watched closely after giving birth and at regular doctor's appointments to screen for signs of diabetes. Many women with gestational diabetes develop diabetes within 5 - 10 years after delivery. The risk may be increased in obese women.
- Delivery-related complications due to the infant's large size
- Development of diabetes later in life
- Increased risk of newborn death and stillbirth
- Low blood sugar (glucose) or illness in the newborn
Calling your health care provider
Call your health care provider if you are pregnant and you have symptoms of diabetes.
Beginning prenatal care early and having regular prenatal visits helps improve your health and the health of your baby. Knowing the risk factors for gestational diabetes and having prenatal screening at 24 - 28 weeks into the pregnancy will help detect gestational diabetes early.
If you are overweight, decreasing your body mass index (BMI) to a normal range before you get pregnant will decrease your risk of developing gestational diabetes.
Screening for gestational diabetes mellitus: Recommendation statement. Rockville, MD. US Preventive Services Task Force. Ann Intern Med. 2008; 148:759-765.
Landon MB, Catalano PM, Gabbe SG. Diabetes mellitus complicating pregnancy. In: Gabbe SG, Niebyl JR, Simpson JL, eds. Obstetrics - Normal and Problem Pregnancies. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2007:chap 37.
Metzger BE, Buchanan Ta, Coustan Dr, de Leiva A, Dunger DB, Hadden DR, et al. Summary and recommendations of the Fifth International Workshop-Conference on Gestational Diabetes Mellitus. Diabetes Care. 2007;30:S251-S260.
American Diabetes Association. Nutrition recommendations and interventions for diabetes: a position statement of the American Diabetes Association. Diabetes Care. 2008;31:S61-S78.
Reviewed By: Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Redmond, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.