Gestational diabetes is a disorder in which the body does not make enough insulin or is unable to use all of the insulin needed during pregnancy. Insulin is a hormone that helps the body convert food into energy. Without insulin, glucose (sugar) from the food you eat cannot enter cells and glucose builds up in the blood. Body tissues become starved for energy. The excess sugar in the blood can cross the placenta and cause problems for the baby. By definition, this condition occurs in women with no history of diabetes.

Causes

The reason some women develop gestational diabetes is unknown. Contributing factors include:

• Hormones needed for the baby's growth interfere with and block insulin's performance.

• Excess weight increases insulin resistance.

• Insulin resistance prevents the body from effectively using the insulin that is produced.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

Risk factors include:

• Obesity or being overweight

• Family members with diabetes

• Age: 25 or older

• Race: Hispanic, African-American, Native-American, Asian-American, Indigenous Australian, or a Pacific Islanders

• Gestational diabetes in a previous pregnancy

• Previous delivery of a large baby

• Previous stillbirth or too much fluid surrounding a baby during pregnancy

• Glucose in urine

Symptoms

Gestational diabetes may not cause any symptoms. If symptoms occur, they may include:

• Increased urination

• Thirst

• Hunger

• Recurring vaginal or urinary tract infections

• Weakness

Screening and Diagnosis

If you are at high risk of developing gestational diabetes: very obese, prior history of gestational diabetes, glucose in your urine, or a strong family history of diabetes—your doctor may recommend that you undergo glucose testing as soon as possible. If your initial test is not positive you should be retested between 24-28 weeks of gestation.

Women who are of average risk should be given the 50-gram glucose screening test between 24-28 weeks of gestation.

Newer guidelines do not require glucose testing for low-risk women, but to be low risk you must meet all of the following criteria:

• less than 25 years of age

• normal weight before and during pregnancy

• member of an ethnic group with a low risk of gestational diabetes

• no known diabetes in any siblings or parents

• no history of abnormal glucose tolerance, and

• no history of poor obstetric outcomes.

The screening test involves:

• Drinking a liquid high in sugar

• Taking a blood sample to measure the level of sugar in the blood

• A longer glucose-tolerance test if the initial screening test shows an above normal sugar level

Treatment

Gestational diabetes treatment aims to return blood sugar levels to normal.

Treatment includes:

Diet

• Eat a balanced diet, generally between 2,000-2,400 calories.

• Eat plenty of fruits, vegetables, and fiber.

• Limit the amount of fat you eat.

• Eat adequate amounts of protein and low-fat dairy products.

• Avoid foods high in sugar.

• Eat moderate portions of food at each meal.

• Eat a bedtime snack with protein and a starchy food.

• Do not gain more than the recommended amount of weight during pregnancy.

• Keep a record of your food intake to help a dietitian or a doctor revise your nutritional needs.

Exercise

Physical activity helps the body use blood sugar. The insulin you produce will be more effective. Follow your doctor's recommendations for activity levels and restrictions.

Blood Sugar Testing

Check your blood sugar levels during the day with an easy-to-use monitor. Keep a record of the results and show the doctor at prenatal visits.

Insulin

If your blood sugars remain above normal, despite exercise and diet, you may need one or two injections of insulin each day.

Follow-up

After delivery, blood sugar levels usually return to normal. You will need a glucose tolerance test 6-8 weeks after delivery. Exercise, breastfeeding, and weight loss in the weeks following childbirth help reduce the risk of developing type II diabetes.

Prevention

The following lifestyle changes may help you to avoid gestational diabetes:

• Maintain normal weight gain during pregnancy.

• Eat a healthy diet, one that is low in saturated fat and rich in fruits, vegetables, and whole grains.

• Exercise regularly. Do not start an exercise program until you check with the doctor.

RESOURCES:

American College of Obstetricians and Gynecologists
http://www.acog.org

American Diabetes Association
http://www.diabetes.org

References:

American Diabetes Association. Gestational Diabetes Mellitus, Position Statement. Diabetes Care. 2003; 26 (Suppl 1):S103-105.

American Dietetic Association. Nutrition practice guidelines for gestational diabetes mellitus. American Dietetic Association. 2001 Sep.

Buchanan TA, Xiang AH: Gestational diabetes mellitus. J Clin Invest. 2005;115:485-91.

National Center for Chronic Disease Prevention and Health Promotion website. Available at: http://www.cdc.gov/nccdphp/. Accessed October 7, 2005.

Taylor JS, Kaemar JE, Nothnagh M, Lawrence RA. A systematic review of the literature associating breastfeeding with type 2 diabetes and gestational diabetes. J Am Coll Nutr. 2005; 24: 320-6.

What is gestational diabetes? National Institute of Child Health and Human Development website. Available at: http://www.nichd.nih.gov/publications/pubs/gdm/sub1.htm. Accessed October 7, 2005.