What is gestational diabetes?

Gestational diabetes mellitus (or GDM) is a type of diabetes that develops for the first time during pregnancy.

By: Sarah Kilch Gaffney
March 23, 2021

Diabetes mellitus includes a number of conditions that affect the way your body utilizes blood sugar (also called glucose). There are several different types of diabetes, including type 1, type 2, and prediabetes, as well as gestational diabetes, which occurs during pregnancy. Our bodies produce a hormone called insulin, which helps maintain blood sugar levels, and diabetes develops when there is not enough insulin produced or when the insulin present is not effective enough. With any type of diabetes, your blood sugar levels can get too high, which can lead to a number of health issues.

What is gestational diabetes and how is it determined?

Gestational diabetes mellitus (or GDM) is a type of diabetes that develops for the first time during pregnancy. According to the March of Dimes, about 7 percent of pregnant women in the United States develop GDM.

Most providers will screen for GDM when you are between 24 and 28 weeks along. If you are at higher risk for GDM, discussed below, your provider may want to do the screening earlier. The glucose screening test typically involves consuming a very sweet drink (which does not taste good, but often tastes better if you drink it chilled) and then having your blood sugar levels tested an hour later. Be sure you follow the instructions from your provider precisely. A blood sugar level lower than 140 mg/dL is usually considered normal on this test and indicates that your body can effectively respond to an increased demand for insulin.

Gestational diabetes mellitus (or GDM) is a type of diabetes that develops for the first time during pregnancy.

If your glucose screening test comes back negative—congratulations! If your screening test comes back positive, it does not necessarily mean that you have GDM, but your provider will want to do a different glucose tolerance test to confirm. This glucose tolerance test takes a bit longer (usually around three hours). Again, make sure you follow the exact instructions from your provider.

What are the symptoms of gestational diabetes?

Possible symptoms include increased thirst and frequency of urination, but screening is especially important because most women do not experience symptoms.

What are the risk factors for gestational diabetes?

Some factors may make it more likely that you could develop GDM, but even women who have no risk factors can develop GDM during pregnancy, so it is very important to follow screening recommendations and report any concerning symptoms to your provider.

While there is no surefire way to prevent GDM, there are some things you can do to reduce your chances of developing it.

These factors may put you at higher risk for GDM:

  • Overweight or obese and not physically active
  • Previous GDM or prediabetes diagnosis
  • Polycystic ovarian syndrome (PCOS)
  • High blood pressure or heart disease
  • Older than 25
  • Diabetes in an immediate family member like a parent or sibling
  • Previously had a baby weighing more than nine pounds
  • Black, Hispanic, American Indian or Asian American

Is there any way to prevent GDM?

While there is no surefire way to prevent GDM, there are some things you can do to reduce your chances of developing it. Starting your pregnancy at a healthy weight, keeping pregnancy weight gain within a healthy range, eating nutritious foods (as much as you’re able; it can be very hard if you are experiencing common pregnancy symptoms like nausea, vomiting, and food aversions), and staying active are all important for preventing GDM.

What complications can occur with GDM?

If left untreated or if not carefully managed, GDM can cause major issues for both you and your baby. Of particular concern with GDM, if your blood sugar levels are uncontrolled, your baby can grow too large, resulting in a condition called macrosomia (when your baby weighs more than 8 pounds, 13 ounces). This can result in complications like:

  • Shoulder dystocia (when your baby’s shoulder gets stuck during delivery)
  • Other birth injuries and trauma
  • Increased risk of hemorrhage for mom
  • C-section delivery due to size or other complications

Other complications can include:

Complications specific to your baby can include:

  • Stillbirth
  • Jaundice
  • Serious breathing problems
  • Low blood sugar
  • Obesity and diabetes later in life

What does treatment look like?

As with most pregnancy complications, if you’re diagnosed with GDM, your provider will probably want to see you more frequently to check on you and your baby. You will also likely have more frequent blood work and ultrasounds.

If you’re struggling with your dietary planning and choices, talking to a registered dietician or someone who specializes in managing diabetes can be helpful.

Treatments for GDM are aimed at controlling your blood sugar and reducing the likelihood of complications for you and your baby, and may include lifestyle changes (like diet and exercise), monitoring your blood sugar, and possibly medication. Medication interventions may include oral blood sugar medications or insulin injections. If you’re struggling with your dietary planning and choices, talking to a registered dietician or someone who specializes in managing diabetes can be helpful. According to the Mayo Clinic, 10-20 percent of women with GDM require insulin therapy to control their blood sugar.

It’s important to follow your providers’ instructions for managing your GDM carefully, and to attend all of your prenatal care appointments, even if you’re feeling OK.

What happens after delivery?

While GDM often goes away after delivery, women who have been diagnosed with GDM are at higher risk of developing type 2 diabetes later in life (which is why it’s important to let your primary care provider know about any pregnancy complications like GDM). According to the CDC, women who develop GDM during pregnancy should be tested for diabetes between 6-12 weeks after delivery, and then every one to three years.

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About the author

Sarah Kilch Gaffney is a writer, brain injury advocate, and homemade-caramel aficionado. She lives in Maine with her family, and you can find her work at www.sarahkilchgaffney.com.

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