Everything You Need to Know About Gestational Diabetes

Published October 2019

From Causes to Symptoms

During pregnancy, a woman’s body has to make adaptions for her baby to get the nourishment needed to grow. The placenta secretes hormones that render the mother resistant to insulin, which reduces the uptake of glucose by a mother’s body and ensures a continuous supply of nutrition to the growing baby, explains Northwestern Medicine Endocrinologist Emily D. Szmuilowicz, MD, MS, endocrine director of the Diabetes in Pregnancy

Program at Northwestern Medicine. “This is a normal change that happens in every pregnant woman,” she adds.

Gestational diabetes (GDM) develops in women who are unable to maintain normal glucose levels in the face of these metabolic changes that occur during normal pregnancy, namely among women who have an underlying predisposition towards developing diabetes. GDM occurs in 2 percent to 10 percent of women during pregnancy, and some studies suggest the rate may be even higher.

Testing for Gestational Diabetes

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

Are overweight or obese
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

Typically GDM causes no symptoms. Your care team will generally perform routine screening for GDM at 24 to 28 weeks of pregnancy, although this may be performed earlier for women at high risk of diabetes.

“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.

With effective treatment, the risks of complications are significantly reduced.

— Emily D. Szmuilowicz, MD

Additionally, research has shown that the mother’s blood glucose level during pregnancy influences the future risk of both obesity and glucose intolerance in her 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 percent to 90 percent of women,” says Dr. Szmuilowicz. Women are advised to eat three small to moderate-sized meals, and two to three snacks that are balanced in whole-grain carbohydrates, protein and unsaturated fats.

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

Woman are advised to check glucose levels fasting (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.

Collaborative care amongst your providers is important throughout pregnancy to help keep you and your baby healthy. For example, Northwestern Medicine OB/GYN and care teamswork with other specialists as needed to care for both of you. “I work collaboratively with obstetricians across Northwestern Medicine,” explains Dr. Szmuilowicz.

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.

“Overall, I think it’s important to look at the diagnosis as an opportunity to see a window into your future health, during an actionable time when you can make a meaningful difference in your long-term health,” says Dr. Szmuilowicz.