Gestational Diabetes
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Gestational Diabetes

(Diabetes, Gestational; GDM; Gestational Onset Diabetes Mellitus [GODM]; Glucose Intolerance During Pregnancy)

En Español (Spanish Version)More InDepth Information on This Condition


This condition happens when 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 builds up in the blood. Body tissue becomes starved for energy. The excess sugar in the blood can cross the placenta and cause problems for the baby.

A Woman With Gestational Diabetes

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The exact cause is unknown. But these factors may contribute to the condition:

  • Hormones needed for the baby's growth interfere with insulin
  • Excess weight increases insulin resistance
  • Insulin resistance prevents the body from effectively using insulin

Risk Factors

These factors increase your chance of developing this condition. Tell your doctor if you have any of these:

  • 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


This condition may not cause any symptoms. If symptoms occur, they may include:

  • Increased urination
  • Thirst
  • Hunger
  • Recurring vaginal or urinary tract infections
  • Weakness


Your Risk

If you are at high risk, you may need glucose testing as soon as possible. If your initial test is negative, you should be retested between 24-28 weeks of gestation.

If you are at average risk, you may be given the 50-gram glucose test. This is given between 24-28 weeks of gestation.

If you are at low risk, you do not need glucose testing. 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
  • No history of poor pregnancy outcomes

Screening Test

This involves:

  • Drinking a liquid high in sugar
  • Taking a blood sample one hour later to measure the glucose level

In some cases, a urine glucose test may be done, but these are not as reliable as the blood test.

Diagnostic Test

This involves:

  • A three-hour glucose-tolerance test if the initial screening test shows an above normal sugar level
  • Glucose monitoring in the morning and after meals


The aim of treatment is to return glucose levels to normal. Treatment includes:


  • Eat a balanced diet.
  • Eat plenty of fruits, vegetables, and fiber.
  • Limit the amount of fat you eat and avoid food 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 share with your doctor.


Physical activity helps the body use glucose. The insulin you produce will be more effective. Ask your doctor about an exercise routine.

Blood Sugar Testing

Use a monitor to check your glucose levels. Show your doctor the results at prenatal visits.


If you've made lifestyle changes and your glucose levels stay above normal, you may need to inject insulin each day.


After delivery, glucose levels usually return to normal. You will need a glucose tolerance test 6-8 weeks after delivery. Exercising, breastfeeding, and losing weight will help to reduce your chance of developing type 2 diabetes.


The following may help prevent this condition:

  • Maintain normal weight gain during pregnancy.
  • Eat a healthy diet.
  • Exercise regularly. Talk to your doctor before starting an exercise program.


American College of Obstetricians and Gynecologists

American Diabetes Association


Canadian Diabetes Association

Women's Health Matters


American Diabetes Association. Position statement: gestational diabetes mellitus. Diabetes Care . 2003;26(suppl 1):S103-105.

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

Buchanan TA, Xiang AH. Gestational diabetes mellitus. J Clin Invest. 2005;115:485-491.

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;24:320-326.

Urine glucose. EBSCO Health Library website. Available at: Updated May 2008. Accessed June 25, 2008.

Urine ketone testing. National Center for Chronic Disease Prevention and Health Promotion website. Available at: Updated December 2005. Accessed June 25, 2008.

What is gestational diabetes? National Institute of Child Health and Human Development website. Available at: . Accessed October 7, 2005.

Last reviewed November 2007 by Jeff Andrews, MD, FRCSC, FACOG

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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