What Is Gestational Diabetes?

Gestational Diabetes: Symptoms, Causes, Treatment

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Gestational diabetes mellitus, often called gestational diabetes, is a common condition in which a person’s blood sugar (glucose) levels increase during pregnancy.

While there are some risk factors that make gestational diabetes more likely, it can also occur in pregnant people with no risk factors.

The American Diabetes Association estimates that gestational diabetes occurs in 10% of pregnancies in the United States.

As long as the condition is detected early and treated, people with this form of diabetes can have healthy pregnancies and deliver healthy babies.

Here’s what you need to know about gestational diabetes.

Pregnant person testing blood sugar

Guido Mieth / Getty Images

Signs and Symptoms

Gestational diabetes generally does not have any symptoms. If a person does have symptoms, they are usually mild and similar to those experienced by people with other forms of diabetes.

If you have gestational diabetes, you may:

  • Feel more hungry and/or thirsty than usual
  • Need to urinate more frequently
  • Feel sick to your stomach and throw up
  • Have blurry vision
  • Lose weight even though you have not changed your eating habits or activity levels

Some symptoms that could be caused by gestational diabetes are also common in pregnancy, such as needing to pee more often and feeling nauseated (morning sickness).

It’s important to talk to your doctor if you have any symptoms that worry you.

Causes

Gestational diabetes occurs when a pregnant person’s blood sugar (glucose) levels get too high (hyperglycemia). Multiple factors, including genetics and changes in the body that are unique to pregnancy, contribute to the development of the condition.

The Placenta and Blood Sugar

During pregnancy, the placenta provides a fetus with the nutrients necessary for it to grow and thrive. This special organ also produces hormones, some of which can cause insulin resistance.

Insulin resistance means that insulin (a hormone) is unable to take glucose from the blood and give it to the body’s cells to use for energy.

Insulin resistance usually happens around 20 to 24 weeks of pregnancy, which is why screenings for gestational diabetes occur at this time.

The pancreas will generally produce more insulin to compensate for hormonal insulin resistance, but some pregnant people’s bodies cannot keep up with insulin production. This leads to elevated blood sugar and a diagnosis of gestational diabetes.

Genetics

Gestational diabetes is thought to be caused by a combination of genetic and environmental risk factors. A genetic predisposition has been suggested because the condition tends to run in families.

Many people who are diagnosed with gestational diabetes have a close family member (a parent or sibling) who also had the condition or who has another form of diabetes (such as type 2 diabetes).

If you have a genetic predisposition to gestational diabetes, it does not mean that you will definitely get the condition while you are pregnant. Other factors, such as your age, weight, activity level, diet, previous pregnancies, and smoking, also contribute to your risk.

Weight

Gaining more weight than is recommended during pregnancy has also been linked to gestational diabetes—particularly in people who were overweight when they became pregnant.

Your doctor will talk to you about your weight goals during your pregnancy. While it’s normal and necessary to gain weight when you are pregnant, your weight goals might be different if you have gestational diabetes.

Diagnosis

Screening for gestational diabetes usually occurs around 20 to 24 weeks of gestation. If you are at an increased risk for gestational diabetes, your doctor might test you for the condition earlier.

Glucose Challenge Test

The main test for gestational diabetes is the glucose challenge. This test is the first step of a two-part approach to diagnosing gestational diabetes.

50g Test (Part 1)

You do not need to fast for the glucose challenge. When you arrive for the test, you will consume 50 grams (g) of a sugary drink. After one hour, a sample of your blood will be taken to test your blood sugar levels.

If your blood sugar is elevated (greater than 140 mg/dl), you will need to return for the second part of the diagnostic process.

100g Test (Part 2)

The next step in testing for gestational diabetes is the oral glucose tolerance test (OGTT). You will need to fast before the test, which involves having a drink that contains 100g of glucose.

Your blood will be taken three times—at one, two, and three hours after you finish the drink.

If two or more of your results meet or exceed the thresholds in the reference range (see the table below), you will be diagnosed with gestational diabetes.

Reference Range for Three-Hour Oral Glucose Tolerance Test for Gestational Diabetes
 Normal Abnormal
Fasting less than 95 mg/dl 95 mg/dl or greater
1 hour less than 180 mg/dl 180 mg/dl or greater
2 hour less than 155 mg/dl 155 mg/dl or greater
3 hour less than 140 mg/dl 140 mg/dl or greater

75g Glucose Tolerance Test

Your doctor might also use the 75g oral glucose tolerance test. You will need to fast for eight hours before the test.

When you arrive, you will drink a 75g glucose beverage. Then, your blood sugar will be tested every 60 minutes for two hours.

A fasting blood sugar of 92 mg/dl or more, 180 mg/dl or more at one hour, or 153 mg/dl or more at two hours indicates gestational diabetes.

Treatment

Managing your blood sugar levels will be a priority if you have gestational diabetes. Your ultimate goal will be to make sure that your blood sugar levels are equal to those of pregnant people who do not have gestational diabetes.

There are several ways to control your blood sugar levels while you are pregnant. Your doctor will help you come up with a treatment plan that meets your needs.

Monitoring and Controlling Blood Sugar

If you have gestational diabetes, you will need to monitor your blood sugar and work on controlling it.

Getting and keeping your blood sugars in a healthy range will mean regularly testing your blood sugar levels, changing your diet, and getting regular physical activity (unless your doctor advises against it).

It will also help if you can work with a registered dietitian or certified diabetes care and education specialist. They can teach you about diabetes self-management, including meal planning, blood sugar testing, and medication management (if needed).

Testing Your Blood Sugar

The first step in keeping your blood glucose levels in a healthy range is knowing what they are. You can keep track of your blood sugar levels by regularly testing them with a glucometer.

You can use a glucometer to prick your finger and get a small drop of blood to place on a test strip that will tell you what your blood glucose level is.

The American Diabetes Association (ADA) suggests that your blood glucose levels fall within certain ranges, depending on when you test them:

  • Before a meal (pre-prandial): 95 mg/dl or less
  • One hour after a meal (postprandial): 140 mg/dl or less
  • Two hours after a meal (postprandial): 120 mg/dl or less

Note, however, that the ADA’s guidelines might not be exactly right for your situation. Your doctor might suggest blood sugar goals for you that are more or less strict than what the ADA recommends.

Insulin

Some people with gestational diabetes need to take a medication called insulin to keep their blood sugar in a healthy range.

There are different types of insulin, but most come with a needle that you will use to give yourself an injection at specific times, such as before you eat.

Needing to take insulin to treat gestational diabetes does not mean that you have “failed” at keeping your blood glucose levels controlled with diet and exercise. It just means that your body needs extra help.

Your doctor or diabetes educator will make sure that you have all the information that you need to use insulin safely. You will learn about insulin storage, injection technique, target blood sugars, and the risk of hypoglycemia.

If you have any questions or concerns about your treatment plan, do not hesitate to speak up.

Nutrition

If you have gestational diabetes, your provider will likely want you to try making some changes to your diet that can help you control your blood sugar levels more effectively.

One of the first steps is to learn about how carbohydrates affect your blood glucose levels.

Carbohydrates

Foods with a lot of carbs impact your blood sugar levels more than any other type of food. You’ll find carbohydrates in starches (bread, pasta, crackers, chips, whole grains, cereals), starchy vegetables (potatoes, corn, peas, etc.), dairy, fruit, legumes, and sugary foods (cookies, cakes, candies).

Everyone responds to carbohydrates differently. You’ll need to figure out how different carbs affect your body when you are working on managing gestational diabetes.

Meal Planning

An effective gestational diabetes meal plan lets you enjoy the pleasure of eating, nourishes your body, and helps keep your blood sugar levels in a healthy range.

It’s important that each plan is individualized, but there are certain key concepts that apply to most situations. Dietary management of gestational diabetes generally includes:

  • Carbohydrate counting (reading labels, measuring food, following a consistent carbohydrate diet)
  • Combining carbohydrates with protein and healthy fat to reduce blood sugar spikes (e.g., Greek yogurt with blueberries and chopped nuts, or whole-grain bread with roasted vegetables and cheese)
  • Choosing fiber-rich carbohydrates (low-sugar fruits, vegetables, whole grains, legumes) to optimize nutrition and reduce blood sugar spikes
  • Reducing intake of processed carbohydrates and desserts that increase blood sugars quickly (cookies, cakes, candy, sweetened beverages—including green juice or smoothies, even if no sugar is added)
  • Limiting foods that are high in saturated and trans fat (fried foods, cakes, cookies, pastries)

Exercise

Getting regular physical activity during pregnancy can have many benefits, but can be especially helpful if you have gestational diabetes.

Exercise can help combat insulin resistance by increasing the utilization of glucose, as well as increasing insulin sensitivity.

Talk to your doctor before you start an exercise routine—especially if you were not already exercising regularly before you got pregnant.

Risk Factors

Certain risk factors—such as your age, weight, and ethnicity—make it more likely that you will be diagnosed with gestational diabetes.

It’s also possible to get the condition even if you do not have any risk factors.

Your chances of getting gestational diabetes are increased if you:

  • Have a history of gestational diabetes in previous pregnancies
  • Have a family history of diabetes
  • Are of certain ethnicities (African, Asian, Hispanic, Native American, or Pacific Island descent)
  • Are overweight or obese
  • Have a sedentary lifestyle
  • Are having or have had a large baby (nine pounds or greater in a previous pregnancy)
  • Are over the age of 25
  • Have a history of high blood pressure
  • Have a history of heart disease
  • Have polycystic ovarian syndrome (PCOS)

Coping

Pregnancy already comes with many changes, and it can be overwhelming to add even more if you have gestational diabetes.

The lifestyle changes that you might be making—like adjusting your diet, getting more exercise, checking your blood sugar, and giving yourself insulin—are necessary to make sure that your pregnancy, labor, and delivery go well.

If you are feeling overwhelmed, it might help to keep in mind that gestational diabetes usually goes away shortly after you give birth.

You do not have to do it alone. Look to the people in your life who can offer support, and ask for help when you need it.

Lean on your medical team for advice, and be sure to talk to them when you have questions or concerns.

Many people find that working with a mental health professional helps them adjust to the changes of pregnancy and parenting even if they do not have a diagnosis like gestational diabetes.

After Delivery

If you are diagnosed with gestational diabetes, it will increase your risk of getting type 2 diabetes in the future. That said, the lifestyle changes that you made during your pregnancy can reduce your risk.

The ADA recommends that people with gestational diabetes get tested for prediabetes and type 2 diabetes at four to 12 weeks after they give birth. Testing should include use of the 75g oral glucose tolerance test and clinically appropriate non-pregnancy diagnostic criteria.

People who have gestational diabetes will also need lifelong screening for prediabetes and type 2 diabetes every three years.

If you are diagnosed with prediabetes after you have given birth, your doctor will want you to keep up with lifestyle changes that can help control your blood sugar levels, such as following a nutritious diet, exercising, reducing stress, and managing your weight.

A Word From Verywell

Being diagnosed with gestational diabetes can be overwhelming, especially since it means you will need to make changes on top of those you are already experiencing with pregnancy. It is key that you work on making these changes to ensure that you and your baby stay healthy and that your labor and delivery go well.

Every person who is pregnant gets screened for gestational diabetes, but if you have certain risk factors, your doctor might want you to do the test sooner.

If you are found to have high blood sugar levels, your doctor will ask you to make changes to your diet and physical activity levels to see if it helps. You will also need to regularly check your blood sugar levels. Some people need to take insulin to keep their blood glucose in control.

Gestational diabetes usually goes away after you give birth. However, your risk of being diagnosed with prediabetes or type 2 diabetes in the future is increased. You’ll need to be tested regularly to make sure that if you do develop these conditions, you can start treating them.

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8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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