Gestational diabetes (GDM)

What is GDM?

GDM is a type of diabetes that you can only get during pregnancy. It often appears in the last half of pregnancy. If you are diagnosed early in your pregnancy, you may have had diabetes before you became pregnant.

What causes GDM?

When you eat your body breaks down food into glucose, also called blood sugar, and uses it as energy. Insulin is a hormone that is made by the pancreas.  It acts like a key that opens the door to the body’s cells. The sugar can then move out of the blood and into the cells to be used for energy. With GDM, your body is not able to make enough insulin to use sugar in the normal way.

During pregnancy, the baby’s placenta makes hormones that do not let you use the insulin your pancreas makes as well. This is called insulin resistance. This causes sugar to build up in your blood which leads to GDM.

Glucose and other nutrients are sent to your baby through your blood and the placenta. A change in your blood sugar level will cause a change in your baby’s blood sugar level. The goal is to keep your blood sugar within normal levels.

What symptoms might I feel?

Most women with GDM feel healthy and have no signs.

What are the risks during pregnancy for someone who has GDM?

  • Polyhydramnios (too much amniotic fluid around the baby)
  • Pre-eclampsia (high blood pressure)
  • Macrosomia (large baby)
  • Need for a cesarean section delivery (if the baby is too large and labor is too long)
  • Hypoglycemia (low blood sugars for the baby after delivery)
  • Respiratory distress syndrome (breathing problems for the baby after delivery)
  • Fetal death (It is rare, but a baby may die before delivery for reasons that are not always known.)

What can I do to lower the risks for my baby and myself?

To meet the goals for a healthy pregnancy with GDM, you will be asked to:

  • Check your blood sugar levels
  • Follow a meal plan
  • Exercise
  • Keep all of your doctor appointments

Blood sugar monitoring

A nurse will teach you how to check your blood sugar levels. Check them four times a day. Your levels should be within these ranges:

  • Fasting (in the morning before eating): 60 to 95
  • One hour after the start of each meal: less than 140

If you are not using a Telcare meter, use MyChart to send your blood sugars to your care team. Choose your OB diabetes provider in your MyChart account.

Meal planning

Eat and drink foods that are healthy and taste good while keeping your blood sugar levels in the needed range. Your blood sugar level is affected by all the foods you eat, not just those high in sugar, such as candy, cake, and pie.

A dietitian will talk with you about your dietary needs. They will help you make a plan that is right for you.

Physical activity

Exercise, such as walking after meals, will help lower blood sugar levels. Exercise at the same time each day to help your blood sugar levels stay steady. Be sure to check with your doctor to make sure it is safe for you to exercise during pregnancy.

Remember to:

  • Keep your heart rate below 140 beats per minute during exercise.
  • Wear diabetes identification.
  • Carry sugar with you, such as hard candy, in case exercising causes your blood sugar to drop too low.


You may need to take medicine. Your doctor will talk with you and write any needed prescriptions.

Prenatal visits

Keep all of your doctor’s visits. Call your provider if you need to reschedule.

If you are a UI Health Care patient, you can call 1-319-356-2294 to reschedule.

What is hypoglycemia (low blood sugar)?

It is when the sugar level in your blood is low. In pregnancy, a blood sugar below 60 mg/dl is too low.

Signs of a low blood sugar may include:

  • Shakiness
  • Racing heart
  • Blurred vision
  • Sweating
  • Headache
  • Feeling nervous
  • Feeling impatient
  • Feeling cranky
  • Hunger
  • Confusion
  • Dizziness or feeling faint
  • Numb lips or tongue
  • Slurred speech

What is hyperglycemia (high blood sugar)?

It is when the sugar level in your blood is above your target range. You may or may not be able to feel when your blood sugar is high.

Signs of a high blood sugar may include:

  • Dry mouth
  • Drowsiness (more tired than normal)
  • Thirst
  • Weight loss
  • Frequent urination
  • Increased appetite (more hungry than normal)
  • Urination overnight
  • Blurry vision

Will I have diabetes after pregnancy?

Most women with GDM no longer have diabetes after they deliver their baby. You may eat and drink as normal again.

A two-hour glucose tolerance test will be done at the first doctor visit after you have your baby to find out if you have Type 2 diabetes. Fast (do not eat) for 8 hours before this test.

How can I lower my chances of getting Type 2 diabetes?

  • Control your weight. If you are overweight lose 5 to 7% of your body weight.
  • Exercise for 30 minutes five times each week.
  • Have your fasting blood sugar checked at least one time every three years.

How do I get rid of my lancets?

It is best to put your lancets in a container that is used only for this purpose to prevent injury, illness, and pollution. Use a coffee can or hard plastic bottle, such as an empty bleach or liquid detergent bottle.

Do not use a container:

  • That will be returned to a store or recycled
  • Is glass
  • Is clear plastic

Seal the lid with heavy-duty tape when the container is full.

Call your local waste department to learn how to get rid of your used syringes safely.

Do not take used lancets, insulin syringes, or needles to the hospital.

Keep all sharps out of the reach of children.

Last reviewed: 
January 2021
Alternative Names: 
Diabetes during pregnancy

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