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Gestational Diabetes


Updated June 01, 2011

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Gestational diabetes occurs in women who have never had diabetes. This is not a disease, but rather a temporary condition in pregnancy in which the mother's hormonal system cannot maintain normal blood sugar levels. In the United States, it is annually diagnosed in about 4% of all pregnancies (about 135,000 pregnancies). It is the most common pregnancy problem.

Most women with gestational diabetes have healthy babies. If blood sugar levels can be kept within a safe range, the risks to mother and baby are about the same as for a woman without it.

Gestational Diabetes Symptoms

Gestational diabetes rarely has symptoms. In rare cases, high blood sugar levels may cause increased urination and excessive thirst.

Gestational Diabetes Causes

The exact cause of gestational diabetes is unknown. Weight gain, hormonal changes, and hormones released from the placenta (which block the action of insulin) can cause insulin resistance. Insulin is a hormone responsible for removing glucose from the bloodstream. When insulin cannot do its job, blood sugar or glucose levels rise. When they rise high enough, gestational diabetes is diagnosed.

Gestational Diabetes Risk Factors

  • Sibling or parent with diabetes.
  • African American, Native American, Asian, Hispanic, or Pacific Islander.
  • Over 25 years old.
  • Overweight.
  • History of gestational diabetes.
  • History giving birth to multiples, a baby over 9 pounds or a baby with a birth defect.
  • History of an unexplained miscarriage or stillbirth.
  • Glucose in urine
  • Prediabetes

Gestational Diabetes Risks to Baby

Gestational diabetes is usually diagnosed later in pregnancy. The baby's body is formed, so there is not a high risk for developmental birth defects.

Insulin cannot cross the placenta to the baby. However, blood sugar can. If the mother's levels are high, the baby's pancreas must produce extra insulin to deal with the excess blood sugar. Blood sugar is a source of energy and can get stored in the baby's body as fat.

High blood sugar levels can cause the following complications for the baby:

  • Macrosomia or a "fat" baby.
  • Shoulder damage during delivery.
  • Increased chance for cesarean section.
  • Low blood sugar levels after delivery.
  • Breathing problems.
  • Slight increase of stillbirth risk
  • Higher risk for obesity and Type 2 diabetes.

Gestational Diabetes Risks to Mother

  • High blood pressure
  • Increased chance for cesarean section
  • Increased risk for Type 2 diabetes
  • Increased risk for gestational diabetes in future pregnancies

Gestational Diabetes Diagnosis Tests

If you are at high risk, your glucose level may be checked at the first prenatal visit and again between 24-28 weeks of pregnancy. If you are at average risk you may be tested between 24-28 weeks of pregnancy.

A fasting or random blood sugar check will first be done. Depending on your blood sugar levels and your risk, you may receive additional tests.

  • Screening Glucose Challenge Test: Your blood sugar level will be checked one hour after drinking a sugary beverage. Further tests may be needed if the results are above normal.
  • Oral Glucose Tolerance Test: Blood sugar will be checked before the test and then at 1 hour, 2 hours, and 3 hours after drinking a sugary beverage. You will be asked to eat normally three days prior and fast 8 hours prior to the test. If your blood sugar level is above normal at least twice, you may be diagnosed with gestational diabetes.

Gestational Diabetes Treatment

  • Meal plan with nutritional counseling if possible.
  • Moderate exercise.
  • Self-monitoring of blood sugar levels with a blood glucose meter.
  • Insulin if needed.
  • Regular blood pressure and urine protein testing.
  • Monitoring for urine ketones if directed by your doctor.
  • Ultrasounds and nonstress tests may be used to monitor fetal well-being and growth.
  • Kick counts to check the baby's activity.

Gestational diabetes will most likely go away after delivery unless it has uncovered preexisting diabetes. You may be asked to return about six weeks after delivery to evaluate your blood sugar levels.


American Diabetes Association. "Gestational Diabetes Mellitus." Diabetes Care Jan 2004 27:1 s88-s90

What I Need to Know About Gestational Diabetes. National Diabetes Clearing House. Accessed: May 1, 2011. http://diabetes.niddk.nih.gov/dm/pubs/gestational/

What is Gestational Diabetes? American Diabetes Association. Accessed : May 1, 2011. http://www.diabetes.org/diabetes-basics/gestational/what-is-gestational-diabetes.html

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