Gestational diabetes is when blood glucose levels are abnormally high during pregnancy due to the body developing a resistance to insulin.

Without treatment, the condition may harm the person and the baby. After the baby is born, symptoms of gestational diabetes usually disappear.

This article discusses what gestational diabetes is, its causes, and how to treat it.

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Gestational diabetes is a condition where blood glucose levels are too high during pregnancy. The signs of gestational diabetes usually begin around the 20–24th week of pregnancy in the second trimester. A doctor usually tests for the condition between the 24th and 28th week of pregnancy.

Excessive levels of glucose in the bloodstream could cause complications for the pregnant person and their unborn baby. This is why it is important that a doctor diagnoses gestational diabetes promptly to ensure blood glucose levels are kept stable.

Around 3%–8% of pregnant people in the United States will develop gestational diabetes.

Blood sugar levels usually return to normal levels after the baby is born, though 50% of people who experience gestational diabetes may develop type 2 diabetes in the future.

Gestational diabetes is a condition that makes a person resistant to insulin. They still produce insulin, but that insulin is no longer effective at reducing blood sugar levels.

Hormones released from the placenta interfere with how well insulin is able to store glucose in fat and muscle cells, so the level of glucose rises in the blood.

All pregnant people will experience some insulin resistance during pregnancy. They are usually able to produce additional insulin to compensate for insulin resistance.

However, people with gestational diabetes do not produce enough insulin to overcome the state of insulin resistance.

Gestational diabetes does not typically cause symptoms. But the condition may cause increased feelings of thirst and a person may notice they are needing to urinate more than usual.

If anyone notices symptoms during pregnancy that are causing them concern, no matter how subtle, they should contact their doctor. People’s experiences of pregnancy vary, and the changes could be a normal part of the pregnancy’s progression, but if a person is worried, contacting a doctor should put their mind at ease.

The goal of treatment is to manage blood glucose levels, usually through changes in lifestyle.

Dietary recommendations

The American Diabetes Association (ADA) recommend a healthful diet for managing blood glucose levels.

Pregnant people in general should aim for:

  • 175 g of carbohydrate
  • 71 g of protein (minimum amount)
  • 28 g of fiber

After receiving a gestational diabetes diagnosis, a person should limit saturated fats and avoid trans fats altogether.

A healthful diet for diabetes includes:

  • foods high in fiber, such as whole-grain pasta or brown bread
  • fish or poultry instead of fatty and processed meats
  • plenty of vegetables and whole fruits
  • unsalted nuts, seeds, and legumes
  • avoiding sweets or foods high in added sugar

The Centers for Disease Control and Prevention (CDC) suggest a person can keep track of what they are eating by keeping track of how many carbohydrates they are eating and implementing the “plate method,” which includes filling half the dinner plate with non-starchy vegetables.

Learn more about counting carbs here.

If someone feels overwhelmed about making food choices after receiving a gestational diabetes diagnosis, they may find talking to a relevant healthcare professional helpful.

Learn more about healthful diets for gestational diabetes here.

Physical activity

Regular physical activity is another important component of managing blood glucose levels. It is important a person speaks with their doctor before increasing physical activity, especially when they are pregnant.

Medication

When lifestyle changes are not working, doctors may prescribe medication to keep a person’s blood glucose levels under control. These medications may include insulin.

According to the American Diabetes Association, a doctor will recommend a pregnant person monitor their blood glucose throughout their pregnancy. If the person is prescribed insulin they may need to measure their blood glucose more frequently to ensure the dose is correct and remains effective.

Healthy glucose levels for women with gestational diabetes are:

  • less than 95 milligrams per deciliter (mm/dL) before meals
  • under 140 mm/dL an hour after eating
  • under 120 mm/dL two hours after eating

Doctors will check for gestational diabetes between the 24th and 28th weeks of pregnancy. They will use blood tests to measure blood glucose levels.

The tests may involve a one- or two-step glucose tolerance test.

The one-step glucose tolerance test requires fasting overnight. A doctor draws blood the next day to get a baseline reading. The person then consumes a drink containing 75 grams (g) of glucose. A doctor draws blood 1 hour later, then waits another hour for a second draw.

The two-step glucose challenge test does not require fasting. Instead, a person consumes a 50 g-glucose drink, with a doctor drawing blood 1 hour later.

If the reading is abnormal, a person may need to do a 3-hour oral glucose tolerance test. This test requires fasting. The person consumes a 100-gram glucose dose and a doctor draws their blood at 1 hour, 2 hours, and 3 hours after the dose.

Having overweight or obesity is a risk factor for gestational diabetes. A person is also at risk if they gain too much weight during pregnancy.

Some other risk factors for gestational diabetes include:

  • a family history of diabetes
  • previously giving birth to an infant greater than 9 pounds
  • having a baby at or after age 25
  • having pre-diabetes

Gestational diabetes does not typically cause birth defects, as this condition occurs starting in the second trimester. Most of the possible complications are manageable.

Examples of possible complications of gestational diabetes for a baby include:

  • early birth
  • high birth weight
  • low blood glucose after birth
  • breathing problems
  • miscarriage or stillbirth

Gestational diabetes may also increase the risk of preeclampsia. This is a condition that causes high blood pressure. It can be life-threatening for the pregnant person and the unborn baby.

People who develop preeclampsia may require an early delivery, which could involve a doctor performing a cesarean delivery.

A person may also be at risk of type 2 diabetes in later life after developing gestational diabetes, so it is important they are mindful of what the symptoms of diabetes are.

Learn more about symptoms of diabetes here.

Living with overweight or obesity increases the risk of gestational diabetes. Eating a healthful diet and making time for regular physical activity are important for maintaining a healthy weight during pregnancy.

However, a person should discuss any potential changes to their diet or physical activity level with a doctor, especially while pregnant.

Learn more about preventing gestational diabetes here.

Gestational diabetes refers to high blood sugar levels during pregnancy. The condition is usually symptomless, but some people could feel thirsty or notice they urinate more often.

People who live with overweight or obesity are at a greater risk of developing gestational diabetes and should be mindful of symptoms while pregnant.

With appropriate treatment, gestational diabetes is a manageable condition. But if left untreated it could lead to serious complications, such as preeclampsia.

In most people, blood sugar levels return to normal after the baby is born. Nevertheless, a person should be mindful of diabetes symptoms as 50% of people who experience gestational diabetes may go on to develop type 2 diabetes.