What Is Gestational Diabetes?
The body’s cells need glucose (sugar) to function properly. Glucose is converted into energy in the cells with the help of the hormone insulin. When there is inadequate insulin, or the body stops responding to the insulin that is produced, sugar can build up in the blood, resulting in diabetes. Pregnancy increases the body’s need for insulin, and women with gestational diabetes do not produce enough.
What Causes Gestational Diabetes?
Gestational diabetes affects nearly 10% of pregnancies, and it is not known why some women develop it while others don’t. Risk factors for developing gestational diabetes include:
- Being overweight/obese
- Having a high amount of abdominal fat
- Family history of diabetes
- Age 25 and older
- Previous pregnancy with gestational diabetes
- Being put on bed rest
- Certain ethnicities: Hispanic-American, African-American, Native American, South or East Asian, or Pacific Islander
- Having Polycystic Ovary Syndrome (PCOS) or a condition linked to problems with insulin
- Past problems with blood sugar or insulin, such as glucose intolerance, insulin resistance, or “prediabetes”
What Are the Symptoms of Gestational Diabetes?
Women are commonly tested for gestational diabetes during pregnancy because it usually has no signs or symptoms. When signs and symptoms do occur, they may be mild and include:
Complications of gestational diabetes include:
- Having a large baby (heavier than 9 pounds).
- This can be dangerous because the baby may not easily fit through the birth canal, causing injury to the baby and to the mother during delivery and complicating a normal delivery.
- A large baby can also necessitate a C-section.
- Early labor and delivery (premature delivery or a “preemie”)
- Respiratory distress syndrome in the baby
- Low blood sugar (hypoglycemia) in the baby upon delivery
- Jaundice (yellowing skin and eyes) in the baby in the days after delivery
- Future diabetes, both in the baby and the mother
- Increased risk for maternal infections
- Increased risk for preeclampsia in the mother, which causes high blood pressure and can be life-threatening for the mother and baby
How is Gestational Diabetes Diagnosed?
Diagnosing gestational diabetes can help reduce the risk of complications during pregnancy.
Women are usually tested for gestational diabetes at 24-28 weeks of pregnancy. Women who have risk factors for gestational diabetes may be tested sooner or more frequently.
There are 2 main ways to test for gestational diabetes:
- Glucose Challenge Test (also called glucose screening test): Blood is drawn 1 hour after drinking a liquid containing glucose (sugars). Fasting is not required for this test. If blood glucose is high (140 or more) the woman may need to have an oral glucose tolerance test while fasting.
- Oral Glucose Tolerance Test (OGTT): This test measures blood glucose after fasting for at least 8 hours. Blood is drawn, then the patient drinks the liquid containing glucose. Blood will then be drawn every hour for 2 to 3 hours in order to diagnose gestational diabetes.
What Is the Treatment for Gestational Diabetes?
Once a woman is diagnosed with gestational diabetes, a key to managing it is to learn to check blood sugar levels. People with diabetes may need to check their blood sugar often. Your doctor will advise you on choosing a blood sugar meter (glucometer) and instruct you how to check blood sugar levels at home. Most women with gestational diabetes are advised to check blood sugar levels four times daily: before eating in the morning, and 1-2 hours following breakfast, lunch, and dinner.
Often, gestational diabetes can be treated with dietary changes and exercise. In some cases, women will need insulin shots or other diabetes medications. The goal of treatment is to reduce the risk of complications such as a large baby (which can result in injury to the baby and/or mother during delivery).
Diet recommendations for women with gestational diabetes may include:
- Eating smaller, more frequent meals with healthy snacks in between
- Eating every few hours
- Avoid sweets and added sugars, including sweetened beverages (soda, juices)
- Eat lean proteins but avoid “high mercury” containing fish and seafood such as King mackerel, shark, swordfish, tilefish, tuna or marlin
- Consume complex carbohydrates such as whole grains, brown rice, quinoa, lentils, and beans
- Eat carbohydrates in moderation
- Limit or avoid fruits and fruit juices, which are high in sugar
- Limit dairy products, even low-fat dairy or “skim” milks
- Consume plenty of non-starchy vegetables such as lettuce, spinach, collard greens, kale, broccoli, tomatoes, onions, green beans, carrots, and mushrooms
Your doctor will discuss dietary changes and may suggest a meal plan to help maintain regular blood sugar levels. You may also consult with a dietician or diabetes specialist to help plan meals and learn about eating plans to help control your blood sugar levels during pregnancy.
Exercise may also help control blood sugar levels. Women who exercised before being diagnosed with gestational diabetes may usually continue their exercise routines unless advised to stop by their doctor. For those who did not exercise, consult your doctor. About 30 minutes of low-impact activity such as walking or swimming on most days is often advised.
About 15% of women with gestational diabetes will require insulin to reduce blood sugar levels. Insulin is administered by injection. Insulin therapy is generally preferred over other diabetes medications because it does not cross the placenta to the fetus. Oral diabetes medicines may be used as an alternative, but they do cross the placenta to the fetus and their effects on a fetus are unknown.
How Can Gestational Diabetes be Prevented?
It is unknown what causes some women to develop gestational diabetes, however, managing risk factors may help prevent it from occurring. Close monitoring by your doctor throughout your pregnancy is also a key to limiting your risk of gestational diabetes. Eat a balanced diet while limiting sweets and sugars, maintain a healthy weight, and exercise regularly before becoming pregnant and continue doing so while pregnant if possible.
What Is the Prognosis for Gestational Diabetes?
If a woman keeps blood sugar levels close to normal during pregnancy, the chances are good for a normal delivery. After delivery, gestational diabetes usually goes away and blood sugar levels return to normal, and insulin is no longer required.
Women with poor glucose control and their babies are at risk for complications such as having a large baby that complicates a normal delivery, premature delivery, neonatal hypoglycemia or respiratory problems, and increased risk of diabetes later in life.
About 20-to-50% of women who had gestational diabetes during pregnancy will develop type 2 diabetes within 10 years. Women who have had gestational diabetes will need to be checked regularly to see if it develops.
Health Solutions From Our Sponsors
Celeste Durnwald, MD. Patient education: Gestational diabetes (Beyond the Basics). 22 October 2019. 3 January 2020.
Diabetes Teaching Center at the University of California, San Francisco. Gestational Diabetes. 2020. 3 January 2020.
National Institute of Diabetes and Digestive and Kidney Diseases. Tests & Diagnosis for Gestational Diabetes. May 2017. 3 January 2020.
The doctors and editors at UpToDate. Patient education: Gestational diabetes (diabetes that starts during pregnancy) (The Basics). 2020. 3 January 2020.