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.

Gestational Diabetes

(Diabetes, Gestational; GDM; Gestational Onset Diabetes Mellitus [GODM]; Glucose Intolerance During Pregnancy)
by Debra Wood, RN
Definition

Glucose comes from the breakdown of food. It is the body's energy source. Assisted by a hormone called insulin, glucose can pass from the blood to the cells. Without insulin, glucose will build up in the blood. This is called hyperglycemia. At the same time, your body's cells are starved for glucose (energy).

When diabetes first occurs during pregnancy it is called gestational diabetes. The extra glucose in the blood can cross to the baby. This condition can cause problems for the mother and baby.

Causes

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

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

These factors increase your chance of developing this condition:

  • Family members with diabetes
  • Age: 25 or older
  • Gestational diabetes in a previous pregnancy
  • Glucose in urine
  • Obesity or being overweight
  • Previous delivery of a large baby
  • Previous stillbirth or too much fluid surrounding a baby during pregnancy
  • Race: Hispanic, African-American, Native-American, Asian-American, Indigenous Australian, or a Pacific Islanders
Symptoms

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

Diagnosis
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. (See Screening Test below.) 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
  • Member of an ethnic group with a low risk of gestational diabetes
  • No history of abnormal glucose tolerance
  • No history of poor pregnancy outcomes
  • No known diabetes in any siblings or parents
  • Normal weight before and during pregnancy
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. 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
Treatment

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

Diet
  • Do not gain more than the recommended amount of weight during pregnancy. Gaining too much weight can increase the risk of having:
  • Eat moderate portions of food at each meal.
  • Eat a balanced diet .
  • Eat plenty of vegetables and fiber .
  • Eat a bedtime snack with protein and a starchy food.
  • Keep a record of your food intake. Share this with your doctor.
  • Limit the amount of fat you eat. Avoid food high in sugar.
Exercise

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.

Medication
Insulin Injections

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

Oral Medicines

Some doctors may choose to prescribe oral medicines to help control your blood sugar levels. Examples of these medicines include:

  • Glyburide (eg, DiaBeta, Glucovance)
  • Metformin (eg, Glucophage)
Follow-up

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 .

Prevention

The following may help prevent this condition:

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

Last reviewed: September 2011 by Ganson Purcell Jr., MD, FACOG, FACPE.

RESOURCES:
CANADIAN RESOURCES:
References:
  • 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.
  • Gutzin S, Kozer E, Magee C, Feig G. Koren G. The safety of oral hypoglycemic agents in the first trimester of pregnancy: a meta-analysis. Can J Pharm. 2003;10(4):179-83.
  • 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: http://www.ebscohost.com/healthLibrary/ . Updated May 2008. Accessed June 25, 2008.
  • Urine ketone testing. National Center for Chronic Disease Prevention and Health Promotion website. Available at: http://www.cdc.gov/nccdphp/ . Updated December 2005. Accessed June 25, 2008.
  • 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.
  • 2/5/2009 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php : Cheng YW, Chung JH, Kurbisch-Block I, Inturrisi M, Shafer S, Caughey AB. Gestational weight gain and gestational diabetes mellitus: perinatal outcomes. Obstet Gynecol. 2008;112:1015-1022. Hillier TA, Pedula KL, Vesco KK, et al. Excess gestational weight gain: modifying fetal macrosomia risk associated with maternal glucose. Obstet Gynecol. 2008;112:1007-1014.
  • 4/1/2011 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php : Dhulkotia JS, Ola B, Fraser R, Farrell T. Oral hypoglycemic agents vs insulin in management of gestational diabetes: a systematic review and metaanalysis. Am J Obstet Gynecol. 2010;203(5):457.e1-9.