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Gestational Diabetes

Medically reviewed by Last updated on Aug 31, 2022.

What is gestational diabetes (GDM)?

GDM is a type of diabetes that develops during pregnancy, usually in the second or third trimester. GDM causes your blood sugar level to rise too high. This can harm you and your unborn baby. Blood sugar levels usually go back to normal after the baby is born.

What causes GDM?

The cause of GDM is not known. Hormones made by the placenta may cause insulin resistance. Insulin helps move sugar out of the blood so it can be used for energy. Insulin resistance means your pancreas makes insulin, but your body cannot use it. As the placenta grows, more of these hormones are produced. The hormones block insulin and cause your blood sugar level to rise.


What increases my risk for GDM?

  • Lack of physical activity, such as exercise
  • A family history of diabetes
  • A history of high blood sugar, blood pressure, or cholesterol levels
  • Being overweight or obese
  • Past delivery of a large baby, pregnant with more than 1 baby
  • Glycosuria (sugar in your urine) or polycystic ovary syndrome (PCOS)
  • Being African American, Latino, Native American, Asian American, or Pacific Islander heritage

What are the signs and symptoms of GDM?

  • More hunger or thirst than usual
  • Having to urinate often
  • Blurred vision
  • Feeling more tired than usual
  • Bladder, vagina, or skin infections that happen often
  • More weight gain than your healthcare provider suggests during your pregnancy
  • Nausea or vomiting

How is GDM diagnosed?

An oral glucose tolerance test (OGTT) may be done at or after 24 weeks of pregnancy. Your healthcare provider may order either a 1-step or 2-step OGTT.

  • 1-step OGTT: Your blood sugar level will be tested after you have not eaten for 8 hours (fasting). You will then be given a glucose drink. Your level will be tested again 1 hour and 2 hours after you finish the drink.
  • 2-step OGTT: You do not have to fast for the first part of the test. You will have the glucose drink at any time of day. Your blood sugar level will be checked 1 hour later. If your blood sugar is higher than a certain level, another test will be ordered. You will fast and your blood sugar level will be tested. You will have the glucose drink. Your blood will be tested again 1 hour, 2 hours, and 3 hours after you finish the glucose drink.

How is GDM controlled?

GDM may be controlled with meal planning and physical activity. The goal is to keep your blood sugar level as close to normal, as safely as possible. Your healthcare provider and dietitian will help set up a meal and activity plan for you.

  • Follow your meal plan as directed. Talk to a dietitian or healthcare provider about the best meal plan for you. He or she may recommend that you eat 3 small meals and 2 to 4 snacks every day. Control the amount of carbohydrates (such as bread, cereal, and fruit) you eat at each meal and snack. Too much carbohydrate in 1 meal or snack can cause your blood sugar to rise to a high level. Your dietitian or provider will tell you how much carbohydrate to eat at each meal and snack. Eat foods that are a good source of fiber, such as vegetables and legumes (beans and lentils).

  • Ask your provider about the best physical activity plan for you. Physical activity helps keep your blood sugar level steady. A good goal is to be active for at least 30 minutes, 5 days a week. Low-impact activities such as walking or swimming are effective.
    Walking During Pregnancy
  • Insulin may be needed if your diabetes is not controlled by nutrition and physical activity. Insulin is safe to use during pregnancy. Insulin may be given by injections, or you may have an insulin pump or pen. An insulin pump is an implanted device that gives you a constant amount of insulin through the day. The amount changes when the number of carbohydrates are entered. An insulin pen is a device prefilled with the right amount of insulin. You and your care team will discuss which method is best for you.
    Insulin Pen

How do I check my blood sugar level?

  • Your healthcare provider will teach you how to check your blood sugar level. You will learn what your blood sugar level should be. You will be given information on when to check your blood sugar level. You will learn what to do if the level is too high or too low. You may need to check a drop of blood in a glucose test machine. Your care team provider may recommend a continuous glucose monitor (CGM). A CGM is a device that is worn at all times. The CGM checks your blood sugar every 5 minutes. It sends results to an electronic device such as a smart phone.
    How to check your blood sugar
    Continuous Glucose Monitoring
  • Ask your provider what your blood sugar levels should be before and after you eat. He or she may suggest that your blood sugar level should be at or below 95 mg/dL before you eat. The level may need to be at or below 140 mg/dL 1 hour after you eat or at or below 120 mg/dL 2 hours after you eat. Your provider may give you higher target levels if you are at risk for hypoglycemia. Write down your results, and show them to your provider. He or she may use the results to make changes to your medicine, food, and physical activity schedules.

Treatment options

The following list of medications are in some way related to or used in the treatment of this condition.

View more treatment options

What else do I need to know about GDM?

  • Your A1c level may be checked. A hemoglobin A1c is a blood test that measures your average blood sugar level for the past 2 to 3 months. It is also called an HbA1c or glycohemoglobin test. The level is given as a percentage. An A1c of 6% or lower is usually recommended during pregnancy. If you are at risk for hypoglycemia, your goal may be 7%. Changes to your nutrition, physical activity, or medicine plan may be made to help you reach your goal. Your provider may recommend that you have your A1c checked 1 time each month.
  • Check your blood pressure often. High blood pressure can cause problems with your health and your pregnancy. Blood pressure readings are usually written as 2 numbers. Your systolic blood pressure (the first number) should be between 110 and 129. Your diastolic blood pressure (the second number) should be between 65 and 79.
    How to take a Blood Pressure
  • Maintain a healthy weight. A healthy weight can help you control your GDM. Ask your healthcare provider how much weight is healthy for you to gain during your pregnancy. If you were overweight before you became pregnant, he or she may recommend a safe weight loss plan during pregnancy. Your provider or a dietitian can help you create a healthy meal plan for you and your baby. Do not try to go on a crash diet or try to lose weight without your provider's approval. You may not get enough calories or nutrients for you and your baby.
  • Do not smoke. Nicotine is dangerous for you and your baby and can make it harder to manage GDM. Do not use e-cigarettes or smokeless tobacco in place of cigarettes or to help you quit. They still contain nicotine. Ask your provider for information if you currently smoke and need help quitting.
  • You may need diabetes screening after you give birth. Screening may be done 4 to 12 weeks after your baby is born. This is to check if you have developed diabetes, problems with your fasting glucose levels, or glucose intolerance. You may need other tests or treatment if you have any of these. Testing may be repeated every 1 to 3 years if you had GDM but normal tests within 12 weeks of giving birth.

Call your local emergency number (911 in the US) if:

  • Your heartbeat is fast and weak, or your breathing is fast and shallow.
  • You are more sleepy than usual or become confused.
  • You have blurred or double vision.

When should I seek immediate care?

  • Your breath has a fruity, sweet smell.
  • You are shaking or sweating.
  • Your blood sugar level is below 70 mg/dL or above 250 mg/dL and does not improve with treatment.
  • You have a headache, or you are dizzy.

When should I call my doctor or diabetes care team provider?

  • You think your baby is not moving as much as usual.
  • You have more hunger or thirst than usual.
  • You are urinating more often than usual.
  • You have an upset stomach and are vomiting.
  • You have questions or concerns about your condition or care.

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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Learn more about Gestational Diabetes

Treatment options

Care guides

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