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Gestational Diabetes


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 you give birth.

What causes GDM?

The cause of GDM is not known. The 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 exercise
  • A close family member with diabetes
  • A history of high blood sugar, high blood pressure, or high cholesterol
  • Being overweight or obese
  • Previous delivery of a large 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
  • Frequent urination
  • Blurred vision
  • More fatigue (tired) than usual
  • Frequent bladder, vaginal, or skin infections
  • More weight gain than your healthcare provider suggests during your pregnancy
  • Nausea or vomiting

How is GDM diagnosed?

An oral glucose tolerance test (OGTT) is usually done between 24 and 28 weeks of pregnancy. Your healthcare provider may order either a one-step or two-step OGTT.

  • One-step OGTT: Your blood sugar will be tested after you have not eaten for 8 hours (fasting). You will then be given a glucose drink. Your blood sugar will be tested again 1 hour and 2 hours after you finish the drink.
  • Two-step OGTT: You do not have to fast for the first part of the test. You will drink 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 drink 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 exercise. 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 exercise 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 healthcare 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 healthcare provider about the best exercise plan for you. Exercise helps keep your blood sugar level steady. A good goal is to exercise for at least 30 minutes, 5 days a week. Low-impact exercises such as walking or swimming are effective.
  • Insulin may be needed if your diabetes is not controlled by nutrition and exercise. Insulin is safe to use during pregnancy.

What else do I need to know about GDM?

  • 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.
  • Maintain a healthy weight. Ask your healthcare provider how much you should weigh. A healthy weight can help you control your GDM. Ask him or her how much weight is healthy for you to gain during your pregnancy. If you were overweight before you became pregnant, your provider may recommend a safe weight loss plan during pregnancy. He or she will make sure you are getting enough calories for your baby. 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.
  • Do not smoke. Nicotine is dangerous for you and your baby and can make it harder to manage your GDM. Do not use e-cigarettes or smokeless tobacco in place of cigarettes or to help you quit. They still contain nicotine. Ask your healthcare 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.

How do I check my blood sugar levels?

  • You will be taught how to check a small drop of blood in a glucose monitor. Ask your healthcare provider when and how often to check your blood sugar level during the day. You may need to check your blood sugar level at least 3 times each day.
    How to check your blood sugar
  • Ask your healthcare 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. Write down your results, and show them to your healthcare provider. He or she may use the results to make changes to your medicine, food, and exercise schedules.

What are the risks of GDM?

You have an increased risk for premature (early) labor or a C-section delivery. You may develop GDM with future pregnancies. You have a higher risk for bladder or vaginal infections. You may develop diabetes after you deliver your baby. Your baby may weigh more than 8½ pounds at birth. He or she may also develop hypoglycemia (low blood sugar) after birth. He or she may also develop newborn jaundice (yellowing of the skin).

When should I seek immediate care?

  • 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.
  • Your breath has a fruity, sweet smell.
  • You are shaking or sweating.

When should I contact my healthcare provider?

  • 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.
  • 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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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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