Measles Information

Pregnant woman testing her blood sugar at home.
Pregnant woman testing her blood sugar at home.

Everything You Need to Know About Gestational Diabetes

From Causes to Symptoms

During pregnancy, your body your body changes to make sure your baby (or babies in twin and multiple pregnancies) gets the nourishment needed to grow.

Your placenta passes oxygen and nutrients to your baby. It also secretes hormones that make you resistant to insulin. Insulin helps regulate the amount of glucose (sugar) in your blood and ensures a continuous supply of nutrition to your growing baby.

Gestational diabetes mellitus (GDM) occurs when pregnant people are unable to maintain normal glucose levels in the face of these hormonal changes that occur during normal pregnancy.

GDM occurs in more than 8% of pregnant people in the U.S.

Northwestern Medicine Endocrinologist Emily D. Szmuilowicz, MD, MS, director of the Diabetes in Pregnancy Program at Northwestern Medicine, shares what you need to know about GDM.

Testing for Gestational Diabetes

Typically, GDM causes no symptoms. However, it can cause pregnancy complications, including large babies, which can mean difficult deliveries, and risk that the children will have issues managing their blood sugar, which is why it’s important to test for it.

Your care team will generally perform routine screening for GDM at 24 to 28 weeks of pregnancy, although this may be performed earlier if you are at high risk of diabetes. The test involves drinking a small sugary beverage and then getting your blood drawn after one hour to see how your body responded to the increase in glucose. You are not supposed to walk around during this hour, as exercise can decrease your blood sugar levels. If your blood sugar levels are still high after this hour, your care team may recommend a second glucose test, during which you wait three hours instead of one before getting your labs drawn.

There are many well-known factors that increase your risk for developing GDM. You may be at higher risk if you:

  • Have excess weight or obesity
  • Are physically inactive
  • Had GDM in a previous pregnancy
  • Have a personal history of prediabetes
  • Are more than 25 years old
  • Had a very large baby (9 pounds or more) in a previous pregnancy
  • Have high blood pressure, a history of heart disease or polycystic ovary syndrome (PCOS)
  • Are a member of a higher-risk ethnic group
  • Have a family history of diabetes, particularly in a first-degree relative
  • Have a twin or multiples pregnancy (Gestational diabetes is two to three times more common in twin and multiples pregnancies, as you typically have multiple placentas or a larger placenta.)

Implications of GDM

“GDM is a quintessential example of the concept of pregnancy as a ‘window’ into a woman's future health,” says Dr. Szmuilowicz. “The metabolic stress of pregnancy enables an underlying predisposition to diabetes to become known at a young age, when a woman may be able to enact the lifestyle modifications that could stave off future disease.” As a result, the diagnosis of GDM has important implications for the long-term health of the mother.

Additionally, research has shown that the mother’s blood glucose level during pregnancy influences the future risk of both obesity and glucose intolerance in their child. This means they may be more likely to have prediabetes.

Managing Gestational Diabetes

The mainstay of treatment for GDM is medical nutrition therapy, which is “sufficient for 80% to 90% of pregnant people,” says Dr. Szmuilowicz. This involves making sure you are eating the proper amount of carbohydrates and balancing them with protein and unsaturated fats.  

“We emphasize the need to pair protein with carbohydrates at meals and snacks to help blunt the after-meal carbohydrate-induced rise in glucose levels,” says Dr. Szmuilowicz.

People with GDM are advised to check glucose levels with a fasting finger prick (before breakfast), and one hour after each meal. When glucose goals are not met through nutrition therapy alone, insulin therapy is introduced and frequently adjusted based on glucose monitoring.

“Fortunately, with effective treatment, the risks of complications are reduced,” adds Dr. Szmuilowicz.

Typically, GDM goes away after you deliver your baby, but your care team will likely check your glucose levels at a postpartum visit to ensure that your blood sugar levels have returned to normal.

Bottom Line

Changes throughout pregnancy are normal ― and necessary ― for your baby to grow. Your care team will routinely screen you for GDM during pregnancy. Care for GDM is important for you and your baby not just during pregnancy, but also for your and your baby’s long-term health.

Take a diabetes risk assessment.