Gestational diabetes: Causes, risk factors & treatments

By Jenilee Matz, MPH Jun 21, 2021 • 9 min

Gestational diabetes is a type of diabetes that affects some women during pregnancy.

In diabetes, the body loses its ability to regulate blood glucose (sugar) levels. Too much glucose in the blood can cause health problems for a pregnant woman and her baby. If you're diagnosed with gestational diabetes, it's important to manage your blood glucose levels. Here are more details on gestational diabetes.

What is gestational diabetes?

In gestational diabetes, blood glucose levels rise higher than normal. This could potentially cause your baby to:

  • Be born too early
  • Weigh 9 pounds or more, which increases the risk of trauma and injury during birth
  • Have trouble breathing
  • Have hypoglycemia (low blood sugar) right after birth
  • Develop jaundice (yellowing of the skin and eyes due to high levels of bilirubin, a substance the body makes when it breaks down old red blood cells)

Gestational diabetes can be risky for moms, too. High blood glucose levels during pregnancy can increase the risk of the following:

  • Preeclampsia, a pregnancy condition marked by high blood pressure and too much protein in the urine. Preeclampsia can be life-threatening, and the only cure for it is to give birth. Your baby may need to be delivered early, before they are fully grown.
  • Having a large baby. This increases the risk of heavy bleeding after birth, a difficult labor and delivery by cesarean or C-section, which is a major surgery. If you're able to have a vaginal birth, a large baby raises the chance of severe tears in the vagina or the area between the vagina and anus.

In most cases, gestational diabetes goes away shortly after the delivery. However, it's important to be checked for diabetes after your baby is born. You will also need to be tested for diabetes every few years. This is because about 50% of women who have gestational diabetes develop type 2 diabetes later in life.

What causes gestational diabetes?

Gestational diabetes occurs when your body can't make enough insulin needed during pregnancy. Insulin, a hormone made in your pancreas, helps your body move glucose from the blood into the cells, where it's used for energy.

During pregnancy, your body produces more hormones and goes through other changes, such as weight gain. These changes can make it more difficult for your body to use insulin properly. Most pregnant women can make more insulin to help move glucose from the blood into the cells. Gestational diabetes develops if the pancreas isn't able to produce enough insulin during pregnancy. Without enough insulin, glucose stays in the blood and the levels rise.

Risk factors for gestational diabetes

Gestational diabetes can happen during any pregnancy, but it's more likely in pregnant women who have certain risk factors. The more risk factors you have, the higher your chance of the disease. Gestational diabetes is more likely in women who:

  • Are overweight or obese before becoming pregnant
  • Gained excess weight during the first part of pregnancy
  • Do not exercise
  • Had gestational diabetes in a past pregnancy
  • Gave birth to a baby who weighed 9 pounds or more
  • Have high blood pressure, high cholesterol or high triglyceride levels
  • Have certain other medical issues, such as polycystic ovarian syndrome (PCOS), heart disease or metabolic syndrome
  • Have a family history of diabetes
  • Are African American, Hispanic, Asian American, Native American or Pacific Islander
  • Are pregnant with more than one baby

How common is gestational diabetes?

The Centers for Disease Control and Prevention (CDC) estimates that gestational diabetes affects 2% to 10% of pregnancies in the United States each year.

Gestational diabetes symptoms

Gestational diabetes doesn't tend to cause symptoms. Some women may have mild signs of gestational diabetes, such as feeling thirstier or urinating more often than normal.

Gestational diabetes testing and diagnosis

All pregnant women should be checked for gestational diabetes. Your healthcare provider will likely test you between weeks 24–28 of pregnancy. However, if you have certain risk factors, you may be tested earlier in pregnancy. Gestational diabetes is diagnosed with blood tests. Your healthcare provider may test you using these methods:

  • One-step approach: You’ll need to fast for at least eight hours and then drink 75 grams of glucose. You’ll have your blood sugar levels checked at fasting, at one hour after drinking the liquid and at two hours after drinking the liquid. Your healthcare provider may diagnose you with gestational diabetes if your blood sugar is:
    • Fasting: 92 mg/dL or higher
    • One hour after drinking 75g of glucose: 180 mg/dL or higher
    • Two hours after drinking 75g of glucose: 153 mg/dL or higher
  • Two-step approach: You don’t have to fast for this test. It is typically done in two steps to confirm a diagnosis. First, you’ll drink a liquid that contains glucose. One hour later, you will have your blood drawn. If your blood sugar reading is 130 mg/dL or more, your healthcare provider will likely have you take a three-hour oral glucose tolerance test at another time before they diagnose you with gestational diabetes.

Gestational diabetes treatment

Your healthcare provider will likely recommend that you follow a treatment plan to bring your blood glucose levels to a healthy range. Following your care plan is a must because it can improve your chance of having a healthy pregnancy and baby. Treatment may involve the following:

  • Testing your blood sugar at home. Your healthcare provider will let you know what your target blood glucose range is and how often to check your blood sugar.
  • Following a gestational diabetes diet. Your provider may suggest you work with a registered dietitian who can create a healthy eating plan for you. They can also teach you how to eat the right amount of food at the right times.
  • Being physically active. Moderate-intensity aerobic exercise, such as brisk walking, can help reduce blood glucose levels. Ask your provider which exercises are safe for you and if there are any special precautions you should take.
  • Keeping up with checkups. See your healthcare provider as often as directed. They'll monitor your health and your baby's development.

If a healthy eating plan and regular exercise aren't enough to manage your blood glucose levels, you may need insulin injections. In some cases, your healthcare provider may prescribe a different diabetes medicine to take by mouth.

When blood glucose levels are too high, gestational diabetes can lead to health consequences for both moms and babies. Know that there are ways to help you reach your target blood glucose levels and reduce your risk of problems. Work closely with your healthcare provider and follow your treatment plan to improve your chances of having a healthy pregnancy and protect the health of your baby.

Clinically reviewed and updated, June 2021.

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