What You Need to Know About Gestational Diabetes

This form of diabetes only affects pregnant women.

Medically reviewed in January 2020

You’ve probably heard of type 1 and type 2 diabetes—and maybe even prediabetes—but did you know there’s another form of the disease that can develop during pregnancy? It’s called gestational diabetes (GD). An estimated 2 to 10 percent of pregnancies are affected by this condition.

Understanding gestational diabetes
When you eat, your body produces a hormone, called insulin, which helps move the sugars from your food that ends up in your blood into your cells so they can be used as energy.

Pregnancy produces hormones that make a woman insulin resistant. Insulin is a hormone that your body uses to regulate blood sugar and use that sugar for energy. Most women will make more insulin during pregnancy to compensate, but some are unable to produce enough insulin, causing higher blood sugar levels leading to GD. Like type 2 diabetes, being overweight increases the risk for gestational diabetes, as does excessive weight gain during pregnancy.

“I think gestational diabetes, in some ways, as being a manifestation of modern life. That it has the hallmarks of type 2 diabetes where there's resistance to insulin and there's high glucose levels in the moms,” says Bruce Chen, MD, of the Fetal Diagnostic Institute of the Pacific in Honolulu. “But it's not a permanent condition, and it's caused by the normal physiology of pregnancy.”

GD is usually diagnosed towards the end of the second trimester, between the 24th and 28th week of pregnancy, although women with certain risk factors may develop it earlier.

Some women are at greater risk
In the U.S., all expectant mothers should be screened for GD, usually between 24 and 28 weeks of pregnancy. The test is a two-stage process. During the first test, women drink a sugary drink and then give a blood sample an hour after finishing the drink. If the woman’s blood glucose levels are in the normal range, she won’t need further testing. If the test shows high blood glucose, the woman will need to go back for a longer test that requires her to fast beforehand and will assess her blood sugar levels several times before and after drinking another sugary drink.

Any pregnant woman can develop the condition, but some are more likely to be diagnosed than others, including those who:

  • are older than 25
  • are overweight (BMI above 25)
  • developed GD in a previous pregnancy
  • delivered a baby that weighed more than nine pounds
  • have a family history of type 2 diabetes or personal history of prediabetes
  • have polycystic ovarian syndrome (PCOS)
  • are of African American, Hispanic/Latino, Native American, Alaska Native, Native Hawaiian or Pacific Islander descent

Women with close relatives who developed gestational diabetes are more likely to develop the condition themselves, suggesting that genetics may also play a role.

Having one or more risk factor doesn’t guarantee a woman will get GD during pregnancy. “Moms can modify their risk by watching what they eat, staying active, and keeping the weight down,” says Dr. Chen.

Complications that may arise
Uncontrolled GD can increase the risk for several complications, such as:

  • preeclampsia, or high blood pressure during pregnancy
  • having a large baby that weighs more than nine pounds, which can make delivery more difficult
  • having a cesarean delivery, or C-section
  • preterm delivery
  • infants born with low blood sugar

Even with treatment, some babies will still grow very large, weighing more than nine pounds, which may require a cesarean delivery, or C-section.

Keeping GD under control
For many women, GD can be managed with diet and exercise. Women are usually asked to monitor their blood glucose levels and will report numbers to healthcare providers to determine an appropriate eating plan. Pregnant women, regardless of GD status are usually recommended to do at least 150 minutes of moderate-intensity exercise (such as brisk walking) weekly during pregnancy, but you should check with your doctor about what type and amount of exercise are right for you.

In Chen’s practice, women typically eat three moderately sized meals a day and three snacks between meals. “We're taking the whole meal plan and spreading it out more evenly through the day, so you don't get huge loads of carbohydrates,” he explains. He also notes that the composition of those meals may be different than a woman is used to. “Most people in the U.S. are eating 50, 60% carbs in their meals. We try to get 30% carbs, 40% protein, 30% fat.”

If diet and exercise aren’t enough to manage GD, healthcare providers may prescribe insulin or other pregnancy-safe drugs to keep blood glucose in check.

Long-term outlook
Any medications or special eating plans women take to manage gestational diabetes are temporary. Treatment ends when the condition resolves after delivery.

“It's remarkable,” Chen says. “As soon as delivery happens and the placenta is out, glucose control is restored very quickly, in a matter of hours.”

Keep in mind however that while GD is temporary, it’s also a predictor for future health concerns for both women and their children. Women who are diagnosed with gestational diabetes are also at increased risk of developing type 2 diabetes and heart disease later in life. Babies born to women with GD are also more likely to be obese and develop type 2 diabetes.

“The statistics vary based on which population you look at,” says Chen, “but the general statistic I like to quote is that five years out from a pregnancy with gestational diabetes, about 15 percent of women will be type 2 diabetics. And 15 years out, 50 percent of them will be.”

If you had GD with one pregnancy, you can reduce your risk of developing type 2 diabetes later in life by returning to a healthy weight after pregnancy and maintaining a healthy lifestyle.

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