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Mayo Clinic Health Library

Gestational diabetes

Updated: 08-26-2020

Overview

Gestational diabetes is diabetes diagnosed for the first time during pregnancy (gestation). Like other types of diabetes, gestational diabetes affects how your cells use sugar (glucose). Gestational diabetes causes high blood sugar that can affect your pregnancy and your baby's health.

While any pregnancy complication is concerning, there's good news. Expectant mothers can help control gestational diabetes by eating healthy foods, exercising and, if necessary, taking medication. Controlling blood sugar can keep you and your baby healthy and prevent a difficult delivery.

In women with gestational diabetes, blood sugar usually returns to normal soon after delivery. But if you've had gestational diabetes, you have a higher risk of getting type 2 diabetes. You'll need to be tested for changes in blood sugar more often.

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Symptoms

For most women, gestational diabetes doesn't cause noticeable signs or symptoms. Increased thirst and more-frequent urination are possible symptoms.

When to see a doctor

If possible, seek health care early — when you first think about trying to get pregnant — so your doctor can check your risk of gestational diabetes along with your overall wellness. Once you're pregnant, your doctor will check you for gestational diabetes as part of your prenatal care.

If you develop gestational diabetes, you may need checkups more often. These are most likely to occur during the last three months of pregnancy, when your doctor will monitor your blood sugar level and your baby's health.

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Causes

Researchers don't yet know why some women get gestational diabetes and others don't. Excess weight before pregnancy often plays a role.

Normally, various hormones work to keep your blood sugar levels in check. But during pregnancy, hormone levels change, making it harder for your body to process blood sugar efficiently. This makes your blood sugar rise.

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Risk factors

Some women have a greater risk of gestational diabetes. Risk factors for gestational diabetes include the following:

  • Overweight and obesity.
  • A lack of physical activity.
  • Previous gestational diabetes or prediabetes.
  • Polycystic ovary syndrome.
  • Diabetes in an immediate family member.
  • Previously delivering a baby weighing more than 9 pounds (4.1 kilograms).
  • Race — Women who are Black, Hispanic, American Indian and Asian American have a higher risk of developing gestational diabetes.
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Complications

Gestational diabetes that's not carefully managed can lead to high blood sugar levels. High blood sugar can cause problems for you and your baby, including an increased likelihood of needing a C-section to deliver.

Complications that may affect your baby

If you have gestational diabetes, your baby may be at increased risk of:

  • Excessive birth weight. Higher than normal blood sugar in mothers can cause their babies to grow too large. Very large babies — those who weigh 9 pounds or more — are more likely to become wedged in the birth canal, have birth injuries or need a C-section birth.
  • Early (preterm) birth. High blood sugar may increase women's risk of early labor and delivery before the due date. Or early delivery may be recommended because the baby is large.
  • Serious breathing difficulties. Babies born early to mothers with gestational diabetes may experience respiratory distress syndrome — a condition that makes breathing difficult.
  • Low blood sugar (hypoglycemia). Sometimes babies of mothers with gestational diabetes have low blood sugar (hypoglycemia) shortly after birth. Severe episodes of hypoglycemia may cause seizures in the baby. Prompt feedings and sometimes an intravenous glucose solution can return the baby's blood sugar level to normal.
  • Obesity and type 2 diabetes later in life. Babies of mothers who have gestational diabetes have a higher risk of developing obesity and type 2 diabetes later in life.
  • Stillbirth. Untreated gestational diabetes can result in a baby's death either before or shortly after birth.

Complications that may affect you

Gestational diabetes may also increase your risk of:

  • High blood pressure and preeclampsia. Gestational diabetes raises your risk of high blood pressure, as well as preeclampsia — a serious complication of pregnancy that causes high blood pressure and other symptoms that can threaten the lives of both mother and baby.
  • Having a surgical delivery (C-section). You're more likely to have a C-section if you have gestational diabetes.
  • Future diabetes. If you have gestational diabetes, you're more likely to get it again during a future pregnancy. You also have a higher risk of type 2 diabetes as you get older.
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Prevention

There are no guarantees when it comes to preventing gestational diabetes — but the more healthy habits you can adopt before pregnancy, the better. If you've had gestational diabetes, these healthy choices may also reduce your risk of having it again in future pregnancies or developing type 2 diabetes in the future.

  • Eat healthy foods. Choose foods high in fiber and low in fat and calories. Focus on fruits, vegetables and whole grains. Strive for variety to help you achieve your goals without compromising taste or nutrition. Watch portion sizes.
  • Keep active. Exercising before and during pregnancy can help protect you from developing gestational diabetes. Aim for 30 minutes of moderate activity on most days of the week. Take a brisk daily walk. Ride your bike. Swim laps. Short bursts of activity — such as parking further away from the store when you run errands or taking a short walk break — all add up too.
  • Start pregnancy at a healthy weight. If you're planning to get pregnant, losing extra weight beforehand may help you have a healthier pregnancy. Focus on making lasting changes to your eating habits that can help you through pregnancy, such as eating more vegetables and fruits.
  • Don't gain more weight than recommended. Gaining some weight during pregnancy is normal and healthy. But gaining too much weight too quickly can up your risk of gestational diabetes. Ask your doctor what a reasonable amount of weight gain is for you.
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Diagnosis

If you're at average risk of gestational diabetes, you'll likely have a screening test during your second trimester — between 24 and 28 weeks of pregnancy.

If you're at high risk of diabetes — for example, if you're overweight or obese before pregnancy or you have a mother, father, sibling or child with diabetes — your doctor may test for diabetes early in pregnancy, likely at your first prenatal visit.

Routine screening for gestational diabetes

Screening tests may vary slightly depending on your health care provider, but generally include:

  • Initial glucose challenge test. You'll drink a syrupy glucose solution. One hour later, you'll have a blood test to measure your blood sugar level. A blood sugar level of 190 milligrams per deciliter (mg/dL), or 10.6 millimoles per liter (mmol/L) indicates gestational diabetes.

    A blood sugar below 140 mg/dL (7.8 mmol/L) is usually considered normal on a glucose challenge test, although this may vary by clinic or lab. If your blood sugar level is higher than normal, you'll need another glucose tolerance test to determine if you have the condition.

  • Follow-up glucose tolerance testing. This test is similar to the initial test — except the sweet solution will have even more sugar and your blood sugar will be checked every hour for three hours. If at least two of the blood sugar readings are higher than expected, you'll be diagnosed with gestational diabetes.
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Treatment

Treatment for gestational diabetes includes:

  • Lifestyle changes
  • Blood sugar monitoring
  • Medication, if necessary

Managing your blood sugar levels helps keep you and your baby healthy. Close management can also help you avoid complications during pregnancy and delivery.

Lifestyle changes

Your lifestyle — how you eat and move — is an important part of keeping your blood sugar levels in a healthy range. Doctors don't advise losing weight during pregnancy — your body is working hard to support your growing baby. But your doctor can help you set weight gain goals based on your weight before pregnancy.

Healthy diet

A healthy diet focuses on fruits, vegetables, whole grains and lean protein — foods that are high in nutrition and fiber and low in fat and calories — and limits highly refined carbohydrates, including sweets. A registered dietitian or a diabetes educator can help you create a meal plan based on your current weight, pregnancy weight gain goals, blood sugar level, exercise habits, food preferences and budget.

Stay active

Regular physical activity plays a key role in every woman's wellness plan before, during and after pregnancy. Exercise lowers your blood sugar, and as an added bonus, regular exercise can help relieve some common discomforts of pregnancy, including back pain, muscle cramps, swelling, constipation and trouble sleeping.

With your doctor's OK, aim for 30 minutes of moderate exercise on most days of the week. If you haven't been active for a while, start slowly and build up gradually. Walking, cycling and swimming are good choices during pregnancy. Everyday activities such as housework and gardening also count.

Monitor your blood sugar

While you're pregnant, your health care team may ask you to check your blood sugar four or more times a day — first thing in the morning and after meals — to make sure your level stays within a healthy range.

Medication

If diet and exercise aren't enough, you may need insulin injections to lower your blood sugar. Between 10% and 20% of women with gestational diabetes need insulin to reach their blood sugar goals. Some doctors prescribe an oral medication to control blood sugar, while others believe more research is needed to confirm that oral drugs are as safe and as effective as injectable insulin to control gestational diabetes.

Close monitoring of your baby

An important part of your treatment plan is close observation of your baby. Your doctor may check your baby's growth and development with repeated ultrasounds or other tests. If you don't go into labor by your due date — or sometimes earlier — your doctor may induce labor. Delivering after your due date may increase the risk of complications for you and your baby.

Follow-up after delivery

Your doctor will check your blood sugar after delivery and again in six to 12 weeks to make sure that your level has returned to normal. If your tests are normal — and most are — you'll need to have your diabetes risk assessed at least every three years.

If future tests indicate type 2 diabetes or prediabetes, talk with your doctor about increasing your prevention efforts or starting a diabetes management plan.

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Coping and support

It's stressful to know you have a condition that can affect your unborn baby's health. But the steps that will help control your blood sugar level — such as eating healthy foods and exercising regularly — can help relieve stress, nourish your baby and help prevent type 2 diabetes in the future.

You may feel better if you learn as much as you can about gestational diabetes. Talk to your health care team, or read books and articles about gestational diabetes. Some women find a support group for women with gestational diabetes helpful.

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Preparing for an appointment

You'll likely find out you have gestational diabetes from routine screening during your pregnancy. Your doctor may refer you to additional health professionals who specialize in diabetes, such as an endocrinologist, a registered dietitian or a diabetes educator. They can help you learn to manage your blood sugar level during your pregnancy.

Here's some information to help you get ready for your appointment and know what to expect from your doctor or other health professional.

What you can do

  • Be aware of pre-appointment restrictions. When you make your appointment, ask if you need to fast for lab tests or do anything else to prepare for diagnostic tests.
  • Write down symptoms you're having, including those that may seem unrelated to gestational diabetes. You may not have noticeable symptoms, but it's good to keep a log of anything unusual you notice.
  • Write down key personal information, including major stresses or recent life changes.
  • Make a list of all medications, including over-the-counter drugs and vitamins or supplements you're taking.
  • Take a family member or friend along, if possible. Someone who accompanies you may remember something that you missed or forgot.

Questions to ask your doctor

Make a list of questions to help make the most of your time with your doctor. For gestational diabetes, some basic questions to ask your doctor include:

  • What can I do to help control my condition?
  • Can you recommend a dietitian or diabetes educator who can help me plan meals, an exercise program and coping strategies?
  • Will I need medication to control my blood sugar?
  • What symptoms should prompt me to seek medical attention?
  • Are there brochures or other printed materials I can take? What websites do you recommend?

What to expect from your doctor

Your doctor is also likely to have questions for you, especially if you're seeing him or her for the first time. Your doctor may ask:

  • Have you experienced increased thirst or excessive urination? If so, when did these symptoms start? How often do you have them?
  • Have you noticed other unusual symptoms?
  • Do you have a parent or sibling who's ever been diagnosed with diabetes?
  • Have you been pregnant before? Did you have gestational diabetes during your previous pregnancies?
  • Did you have other problems in earlier pregnancies?
  • If you have other children, how much did each weigh at birth?
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