Diabetes and Lipid Clinic of Alaska



Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is diabetes that is first discovered during pregnancy. (The word “gestation” means pregnancy.) As with other kinds of diabetes, blood glucose levels are higher than normal. High blood glucose levels during pregnancy can lead to complications for both mother and baby, including an overly large baby, jaundice, and premature birth.

These complications are different from the complications normally associated with type 1 or type 2 diabetes. Many of the complications of gestational diabetes can be prevented through education, attentive medical care, careful eating, and close monitoring.

How Insulin and Glucose Work

Insulin is a hormone that allows glucose to enter your cells to be used for energy. Insulin is made and released from the pancreas, an organ located under your stomach. If the insulin you have does not allow enough glucose into the cells, then you have what is called insulin resistance and need more insulin to overcome it. When glucose does not get into your cells, it backs up and accumulates in the blood, resulting in high blood glucose levels.

Insulin resistance is a major feature of gestational diabetes. It is also a feature of type 2 diabetes.

More About Insulin Resistance

Insulin resistance is like a door that doesn’t want to open because the doorknob is rusty and won’t turn. Your hand is like the insulin. If the doorknob is new and well oiled, it has smooth, easy function and turns readily without a lot of force. Similarly, if you do not have insulin resistance, insulin receptors on your cells work great with just a bit of insulin.

However, if the doorknob is rusty, you may not be able to open the door easily. You might have to use both hands to turn the knob or even throw your weight against the door. Likewise, if you have insulin resistance, you need additional insulin (force) to open your cells to glucose. Your pancreas tries to send out more insulin to open up your cells. However, some people can produce only a certain amount of insulin, while others can produce as much as is needed.

Women who get gestational diabetes or its close relative, type 2 diabetes, have insulin resistance coupled with a limited supply of insulin from the pancreas.

What Happens During Pregnancy?

Gestational diabetes is usually detected during the 5th or 6th month of pregnancy. It usually does not occur earlier in pregnancy because hormones that make cells resistant to insulin are released in increasing amounts as the pregnancy progresses. The release of these hormones is a normal part of pregnancy. Most women can produce enough extra insulin to force the cells to allow glucose to enter. If enough insulin is produced, glucose levels stay in a normal range. However, if not enough insulin is produced, blood glucose levels become elevated.

Because the hormones that make you insulin resistant become more and more abundant during the last 3 or 4 months of pregnancy, pregnant women are usually tested for gestational diabetes during this time. Some women should be tested as early in pregnancy as possible since they are at greater risk. Women have a greater risk of developing gestational diabetes if they:

  • Were overweight before pregnancy
  • Have a strong family history of diabetes
  • Have had gestational diabetes in previous pregnancies
  • Have impaired glucose tolerance
  • Have glucose in their urine

If you have a greater risk of developing gestational diabetes, be sure to discuss this with your healthcare provider as soon as possible so that you can receive early testing.

How Is Gestational Diabetes Detected?

The oral glucose tolerance test is used to screen pregnant women at approximately 24 to 28 weeks of gestation. Most women are screened with a 50-gram 1-hour glucose tolerance test prior to having a 3-hour test. If their blood glucose is 140 mg/dL or above on the screening test, then the 3-hour test is done. Some healthcare providers may skip the 1-hour screening test,  if they suspect that a woman will have to go through a longer test anyway.

During the 3-hour glucose tolerance test, you are given 100 grams of glucose (sugary liquid) to drink. In addition to having your blood tested before drinking the glucose (while fasting), your blood is drawn exactly 1 hour, 2 hours, and 3 hours after drinking the glucose. Gestational diabetes is diagnosed if two or more blood glucose levels equal or exceed the levels listed below:

Blood drawn at:




one hour


two hours


three hours


During the 2-hour glucose tolerance test, you are given 75 grams of glucose to drink. In addition to having your blood tested before drinking the glucose (while fasting), your blood is drawn exactly 1 hour and 2 hours after drinking the glucose. Gestational diabetes is diagnosed if two blood glucose levels equal or exceed the levels listed above.

What If You Have Gestational Diabetes?

If you have gestational diabetes, be sure to educate yourself about the disorder and get help from a certified diabetes educator (CDE). Obtaining a meal plan from a registered dietitian (RD) is the best way to start. Often, eating at regular mealtimes with planned snacks in between meals can get your glucose levels under control. A good meal plan should be well balanced to provide the nutrition you need to support both you and your growing baby.

Just because you have diabetes during pregnancy doesn’t mean that your baby will have diabetes. However, it is important to learn about gestational diabetes, monitor it, and take special care of yourself. In many communities you can attend special classes to find out more about gestational diabetes. You will learn that you are one of many women who get gestational diabetes. In fact, it is estimated that 4% of all pregnancies are affected by diabetes. Of these, 90% are gestational. The good news is that the complications associated with gestational diabetes can usually be prevented.

Take Care of Yourself

If you have gestational diabetes, you will need to do the following to take care of yourself:

  • Eat right.
  • Monitor your blood glucose level.
  • Visit your healthcare provider frequently.
  • Stay as active as your healthcare provider permits.
  • Give yourself insulin, if needed.

Eat Right
Eating right is getting the right balance of carbohydrates (40%), fats (40%), and protein (20%) needed for your baby’s growth and development while maintaining safe blood glucose levels. A registered dietitian who is also a certified diabetes educator is highly qualified to help you develop a plan for eating.

In addition to getting the balance of nutrients listed above, your dietitian may advise you to:

  • Avoid concentrated sweets
  • Avoid convenience foods
  • Eat small, frequent meals
  • Eat a small breakfast
  • Choose high-fiber foods
  • Decrease fat intake
  • Eat more low-calorie foods, such as vegetables, for snacks

Monitor Your Blood Glucose Level

Monitor your blood glucose level four times a day. This involves getting a drop of blood from your finger and placing it on a special reagent strip. The strip is read by a small device that lets you know your glucose level in less than a minute.

You should check your glucose levels first thing in the morning before eating or drinking anything, and 1 or 2 hours after each meal. Fasting glucose levels should be less than 95 mg/dl. Glucose levels measured 1 to 2 hours after meals should be less than 140 and 120, respectively..

You should write your glucose levels in a logbook or have a downloadable glucometer. Take your glucometer diary or glucometer with you when you go to your healthcare provider. This way both you and your healthcare provider can see when your glucose levels get too high or too low. Together you can devise an appropriate treatment plan based on your data.

Visit Your Healthcare Provider Frequently

Frequent monitoring combined with a possible need to readjust your treatment plan means that you will need to have more frequent contact with your healthcare provider. Your provider should also be alert to the development of other pregnancy-related problems. Generally at Diabetes and Lipid Clinic of Alaska, we recommend every other week visits until delivery.

Keep Active

Activity or exercise can be an important part of taking care of your gestational diabetes. One of the benefits of exercise is that it helps to lower blood glucose levels. Staying active around the house doing household chores is one way to help keep your glucose level low. If you already exercise regularly, you may be able to continue. However, to be on the safe side, be sure to ask your healthcare provider how much and what kinds of activity are appropriate.

If you are just beginning an exercise program, you may want to choose exercises that are similar to your usual, everyday activities, such as walking, or exercises that work your upper body.

If you use insulin, exercise may lower your blood glucose levels too much, causing hypoglycemia. Be alert for signs of hypoglycemia (shaky, sweating, weakness, anxiety, weak feelings). Carry a sugar source with you, and take 15 grams of fast-acting carbohydrate. Examples of a 15-gram fast-acting carbohydrate include:

  • 3 or 4 glucose tablets
  • 5 or 6 LifeSavers
  • 1 cup of low-fat milk
  • ½ cup of fruit juice

Rest for 15 minutes and re-treat yourself if necessary. Eat a protein and carbohydrate snack within the next half hour. Examples of a protein and carbohydrate snack include:

  • A meat sandwich
  • A peanut butter sandwich
  • A small amount of cheese and crackers

Check Your Urine for Ketones

The American Diabetes Association recommends that you check your urine for ketones every morning when you first urinate. Ketone monitoring involves dipping a ketone strip into your urine. The strip will change color if you have ketones. By color matching the strip using the color code that comes with the ketone package, you can estimate the amount of ketones in your urine.

The presence of ketones in the urine usually indicates that you are not getting enough carbohydrates or that it has been too long since you last ate. Ketones develop when there is a breakdown of your fat stores in order to supply glucose. Normally, this energy need is met through eating the right amount of carbohydrates at appropriate time intervals.

It is thought that excessive ketones may be harmful to the baby.

What to Expect After Delivery

  • Gestational diabetes usually disappears after birth and your glucose levels will come back down to normal. We recommend a glucose tolerance test is recommended at 12 weeks pos partum to ensure normalization of glucoses.
  • There is no way to know if and when you will develop type 2 diabetes. Stay physically active and keep your weight controlled to lower your risk of getting type 2 diabetes in the future. Have your glucose levels checked at regular intervals.
  • Have your glucose levels checked just prior to attempting your next conception. High glucose levels at conception and early in a pregnancy (during the first 8 weeks) can result in serious fetal malformation or miscarriage.
  • Be alert for the signs and symptoms of high blood glucose levels -- excessive thirst, frequent urination, fatigue, blurred vision, and frequent infections that take a long time to heal.

Gestational Diabetes Is a Serious Condition

Remember -- gestational diabetes is a serious but manageable condition. Prompt and proper treatment can help ensure a happy and healthy outcome for both mother and baby. Please consult with the staff at Diabetes and Lipid Clinic of Alaska.

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