What Is Gestational Diabetes (GD)?

close up of a woman's hands using a blood sugar monitoring device

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What Is Gestational Diabetes (GD)?

Gestational diabetes (GD), also called gestational diabetes mellitus (GDM), is high blood glucose (sugar) levels during pregnancy. Normally, the body produces insulin and effectively uses it to regulate the blood's sugar level. In diabetes, this system is disrupted. Gestational diabetes is distinguished from other forms of diabetes in that the disease is diagnosed for the first time in pregnancy. GD usually goes away soon after delivery, though it increases the risk for type 2 diabetes later in life.

Worldwide, it's estimated that GD occurs in 7% to 10% of pregnancies. About 6% to 9% of pregnant women in the U.S. develop gestational diabetes. These rates have skyrocketed in recent decades, hand-in-hand with the obesity epidemic. In fact, between 2000 and 2010, the occurrence of gestational diabetes in America increased by 56%.

Symptoms

Sometimes, symptoms of GD are noticeable. However, many pregnant women with gestational diabetes only experience mild symptoms, while others do not perceive any symptoms at all. For this reason, routine screening is done during routine prenatal care to catch this often silent disease.

Common symptoms of gestational diabetes include:

  • Blurred vision
  • Fatigue
  • Frequent urination
  • Increased thirst
  • Nausea
  • Vaginal, bladder, and/or skin infections

Diagnosis

GD usually begins after the midpoint of pregnancy (20 weeks or later). Signs of the condition can be detected in both urine and blood. When sugar shows up in prenatal urine screenings, further testing may be indicated. Additionally, all patients are routinely screened for this complication during prenatal care. Patients at high risk for GD may be specifically tested earlier in pregnancy to catch the disease early.

Risk factors for gestational diabetes include the following:

  • Advanced maternal age (many researchers put this at 35 or older)
  • Excessive weight gain in pregnancy
  • History of having a large baby (greater than 9 pounds)
  • Family history of diabetes
  • Lack of physical activity
  • Overweight or obesity
  • Previous gestational diabetes or prediabetes
  • Polycystic ovary syndrome
  • Race (Black, Asian, Latinx, and Indigenous women may be at greater risk)

Testing for GD is often done when you are around five to six months pregnant.

In the U.S., universal prenatal screening is performed via blood testing between 24 and 28 weeks of gestation.

Usually, a glucose screening test is done first, which is known as the glucose challenge test or (GCT). You will be given a sugar drink containing 50g of sugar and then your blood will be drawn an hour later to see how well your body processes glucose over time. If the screening test is positive, it does not mean you have GD but it does mean you are at an increased risk. So, you'll get a glucose tolerance test (GTT), also called a glucose tolerance test. The second test is more comprehensive and monitors the blood sugar levels over 3 hours via multiple blood draws.

Causes

While the risk factors above are considered to be contributing factors, the exact causes of gestational diabetes are still being researched. What is known is that pregnancy is associated with insulin resistance due to placental secretion of various diabetogenic hormones. In most pregnant women, their bodies compensate for this insulin resistance by making more insulin to keep blood sugar levels in check.

However, some pregnant women are not able to produce enough insulin or their bodies become too resistant to insulin for it to be able to control sugar levels. Gestational diabetes develops during pregnancy when the pancreas cannot compensate for insulin resistance, which results in high levels of glucose in the blood.

When your body is unable to make and use insulin effectively in pregnancy, it is called gestational diabetes. When you don't have that ability to use insulin, you cannot properly maintain normal glucose levels in your blood.

Types

Gestational diabetes is diabetes that begins after the pregnancy has started. This condition develops in the second half of pregnancy. The disease of gestational diabetes is not the same as pre-existing diabetes in pregnancy, although symptoms and complications overlap. Women who had diabetes prior to pregnancy are diagnosed as having pre-existing diabetes, rather than gestational diabetes.

There are two main types of non-pregnancy-related diabetes. Type 1 diabetes first appears primarily in children and young adults and involves an inability to make insulin. Type 2 diabetes, which is when the body becomes insulin resistant, usually develops in adulthood.

Impact

Whichever type of diabetes a woman has, the disease needs to be treated during the pregnancy in order to prevent possible complications for the baby and mother. If properly treated, the likelihood of a healthy pregnancy is high. Alternatively, poorly controlled gestational diabetes (or pre-existing diabetes) can have serious consequences.

Because your body isn't able to process insulin and your blood sugar goes up, your baby's blood sugar also goes up. This forces your baby's pancreas to work harder to reduce their blood sugar. Added energy (sugar) is stored as fat. The extra fat can lead to macrosomia, or a very large baby, which is typically considered to be over nine pounds and often makes delivery more difficult.

Other potential problems caused by gestational diabetes include:

  • Increased risk of cesarean section
  • Excessive weight gain in pregnancy
  • Future diabetes
  • High blood pressure (preeclampsia)
  • Low blood sugar (hypoglycemia)
  • Preterm birth
  • Stillbirth
  • Tearing or damage to the vagina and/or perineum during labor

A baby who is born after a pregnancy with gestational diabetes has a greater risk of low blood sugar or hypoglycemia. These babies may have more breathing difficulties at birth. Later in life, these babies are at a greater risk for obesity and developing type 2 diabetes.

Treatment

Treatment for gestational diabetes will be started immediately upon diagnosis. The goal is to keep your blood sugar low and steady to give you and your baby the best shot at a healthy pregnancy and birth. Your treatment will usually include some of the following:

  • Diet: Limiting highly refined carbohydrates (sugars) in favor of nutrient-rich fruits, vegetables, whole grains, and lean proteins is key. A nutritionist or your doctor can help you learn how to make healthy dietary choices that keep your blood sugar at acceptable levels. This advice will include how to plan meals and snack well.
  • Exercise: While intense physical activity is not recommended in late pregnancy, light to moderate exercise is encouraged. An active lifestyle can help keep GD in check.
  • Blood sugar monitoring: Your doctor will advise you on how often you need to test your blood sugar through finger pricks, but it is typically several times a day. You will be taught how to do this on your own.
  • Medication, including insulin injections: Not everyone will need to use insulin. Many people are able to control blood sugar with diet and exercise alone. Your practitioner will monitor your blood sugar to determine if you need additional help from insulin injections.

A Word From Verywell

A diagnosis of gestational diabetes can be scary, but with proper care, you and your baby can stay healthy. In most cases, GD goes away soon after the postpartum period, however around 50% of women who had gestational diabetes will go on to develop type 2 diabetes later in life. Eating healthy and maintaining an active lifestyle are effective ways of staving off (and managing) this chronic condition.

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Article Sources
Verywell Family 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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