What is Gestational Diabetes?

Gestational diabetes (also known as gestational diabetes mellitus or GDM) is defined as a condition found in women who exhibit high blood sugar levels during their pregnancy. GDM has few symptoms and is diagnosed by a simple blood screening required by your OB at or around your 24th week of pregnancy.

A blood test will detect any abnormal increase in your glucose levels. GDM affects between 3-5% of pregnancies and develops around the second trimester between 24 and 28 weeks and typically goes away following delivery.

It is important to note no specific cause has been identified, however medical specialists believe hormones produced during pregnancy interfere with the ability of insulin to manage blood sugar.

Under normal circumstances, the stomach and intestines digest carbohydrates in the foods we eat and turn them into a sugar called glucose. After digestion, glucose is released into the blood stream, becoming a potential energy source for the entire body. In order for glucose to efficiently leave the bloodstream and be changed into energy, insulin, a hormone produced by the pancreas, is necessary.

If your pancreas cannot increase insulin production to counteract the increased level of hormones produced when pregnant, blood sugar levels will rise which means you have gestational diabetes. When someone has diabetes, their body is either not making enough insulin or their cells cannot use it the way they should, causing hyperglycemia, which is a build-up of high glucose levels in the blood.

Although the actual cause of GDM is not yet known, it begins when your body is not able to make and use all of the insulin it needs for pregnancy.

Women with GDM usually produce plenty of insulin. However, the effect of the insulin is partially blocked by other hormones made in the placenta, a condition known as insulin resistance.

In some pregnant women, the pancreas is unable to make the additional insulin to overcome this resistance, resulting in gestational diabetes.

Following Delivery and your future healthcare

Most women with gestational diabetes, will see blood sugar levels return to normal shortly after the baby is born; however, there is a chance GDM may return in future pregnancies. In addition, a relationship seems to exist between women who did have GDM and the development of type 2 diabetes. It is important for women with gestational diabetes to talk with their health care providers about their future risk of diabetes. Often, basic lifestyle changes, combined with consistent medical care may help to prevent type 2 diabetes from developing later down the road.

Symptoms of Gestational Diabetes

Most women with gestational diabetes do not experience noticeable symptoms and are unaware that they have the condition until they are tested. Because symptoms can go unrecognized and women who develop gestational diabetes usually have normal blood sugar levels during the first trimester, it is important that all pregnant women are screened for gestational diabetes between the 24th and 28th weeks of their pregnancy. Some women with gestational diabetes may experience the typical symptoms that people living with diabetes are familiar with due to high levels of glucose being built-up in the bloodstream.

These can include:

  • Increased tiredness or fatigue (Caused by the body being unable to convert glucose into energy)
  • Frequent urination (High glucose levels increase blood flow to the kidneys)
  • Frequent or persistent bladder, vaginal, or skin infections (High glucose levels can cause a weakened immune system defense)
  • Excessive thirst (Due to dehydration from increased urination)
  • Extreme hunger (When glucose is not able to get into the cells from lack of insulin, the body suffers from a depletion of energy, causing hunger)
  • Losing weight despite an increase in appetite (Weight loss occurs because the body is breaking down fats and proteins to make up for a perceived energy deficit)
  • Blurry vision (Increased blood volume causes swelling of the lens of the eye)
  • Nausea or vomiting (From the disruption of the body’s glucose and insulin balance)

Pregnancy in general causes many women to urinate more frequently, feel hungrier and become fatigued, so having these symptoms does not necessarily mean a woman has gestational diabetes. Because gestational diabetes cannot be diagnosed based on a pregnant woman’s symptoms, glucose testing must be done in order to detect it. For many, the first symptom of gestational diabetes is not passing the glucose tolerance test.

Cause and Risk Factors with Gestational Diabetes

No one is exactly sure what causes GDM, but it most likely is due to high levels of certain hormones produced by the placenta during pregnancy. These hormones block the action of insulin, which can then lead to GDM. GDM poses risks to both woman and baby. Since GDM does not occur until after the first trimester of pregnancy, generally birth defects are not a concern. However, there are risks if blood sugars remain too high or are uncontrolled. High blood sugar levels may cause a baby to grow bigger than expected.

This is a condition called macrosomia. A large baby can cause a more difficult delivery. After delivery, babies born to mothers with uncontrolled GDM may have trouble breathing due to immature lungs. A baby could also have a fast drop in his blood sugar level after birth, or be born with jaundice.

Children born to mothers with GDM are more likely to become overweight or obese, and have a higher risk of developing type 2 diabetes later in life. There are also risks to you when you have GDM. Because of the possible complications of birthing a large baby, Cesarean-section deliveries are more common. If you have high blood sugar levels, you also have increased risk of preeclampsia, a serious condition that can develop during pregnancy that causes high blood pressure, swelling, and protein in the urine.

You are more likely to develop GDM in future pregnancies, and there is also a higher risk of developing type 2 diabetes later in life. The best thing you can do to prevent these risks to you and your baby is to control your blood sugar levels by working with your doctor and health care team.

Gestational Diabetes Treatment

Woman with Gestational Diabetes and Nurse

If you are diagnosed with GDM, there are several steps you can take to control your blood sugar levels. The better blood sugar control you have, the less risk there is to both you and your baby.

The most important step is to eat a healthy, balanced diet. Your doctor may refer you to a registered dietitian, who will help you plan three meals and 2-3 snacks per day. It is important to eat meals and snacks at regular times and to try not to skip meals. Balanced meals that contain certain amounts of protein, carbohydrates, and fat keep blood sugar levels as close to normal as possible. Eating less sugar and sweet foods like cookies, candy, and snacks will also help lower blood sugar levels. Your dietitian will encourage you to stop drinking any beverage that contains sugar, such as sweetened tea or coffee, carbonated beverages, or juice drinks.

Regular activity and exercise is also important. You doctor will advise what type of exercise schedule you should follow, but typically 30 minutes per day of activity such as walking, biking, or swimming is good and may help to lower blood sugar levels. If you’ve never exercised before, start with an easy 5-10 minute walk and gradually increase your activity. Be sure to follow your doctor’s specific exercise recommendations.

Your doctor’s office will either regularly test your blood sugar levels or teach you to do this yourself at home. Test your blood sugar in the morning before you eat breakfast and two hours after meals to help your doctor keep track of your progress. Testing your blood sugar helps you and your doctor know that your treatment plan is working.

If your blood sugar levels remain high even with healthy eating and activity, your doctor may prescribe insulin. Your doctor’s office will teach you how to inject insulin to help keep your blood sugar levels normal.

Pregnant woman injecting insulin

Gestational Diabetes Complications

Following a treatment plan administered by your health care professional can help prevent the complications associated with gestational diabetes. The key to managing and avoiding complications is carefully controlling blood glucose levels as soon as the diagnosis is made.

GDM generally does not cause birth defects, as it typically affects the mother in late pregnancy after the baby’s body has been formed. However, if left untreated, other serious complications can occur for both mother and baby.  In gestational diabetes, insulin does not enter the placenta, but the extra glucose your body is producing does, which causes the pancreas of the fetus to produce more insulin in an attempt to use the glucose. Since the baby cannot use all of this extra energy, the additional glucose is converted into fat causing the baby to grow excessively large, a condition known as macrosomia. At birth, these babies also have a high risk of breathing problems and have very low blood glucose levels (hypoglycemia). Later in life, they have an increased risk for developing childhood and adult obesity and type 2 diabetes.

Other possible complications if gestational diabetes is left untreated include:

For the mother:

  • Hypertension (high blood pressure)
  • Preeclampsia (pregnancy-induced hypertension associated with swelling of the face, hands and legs)
  • Increased risk of cesarean section delivery

For the baby:

  • Shoulder dystocia (birth trauma caused by the baby being born larger than normal)
  • Prolonged newborn jaundice (excessive amounts of bilirubin causing yellowing of eyes and skin)
  • Low blood calcium and magnesium levels (causing muscle cramps and spasms)
  • Respiratory distress syndrome
  • Increased risk of stillbirth

Questions to ask your doctor

It is important that you have a complete understanding of GDM and its potential effects on you and your baby. Following are a list of questions to discuss with your doctor that will assist you in avoiding complications and delivering a healthy baby:

  • What type of diet plan and exercise plan will I be on and how strictly do I need to follow them?
  • What other health professionals or specialists will be involved in my care; i.e. a dietitian, diabetes educator or neonatologist.
  • Will I need insulin injections?
  • Will gestational diabetes harm my baby’s development?
  • What are my risks of developing hypertension and preeclampsia?
  • Could my baby become a diabetic later in life?
  • What is my risk of remaining diabetic after delivery or developing the condition again down the road?

Gestational Diabetes Prevention

Pregnant woman holding apple and glucose meter

If you have a brother, sister, or parent with diabetes, your risk of gestational diabetes (GDM) during pregnancy increases. You can decrease your risk of GDM by exercising, losing weight if necessary, and eating healthy foods.

One of the most important things you can do is to increase your daily activity. Aim for at least 30 minutes of activity most days, or 150 minutes of activity per week if approved by your doctor. Activity includes walking, exercise classes, hiking, or even playing outside with your kids. If you can’t be active for 30 minutes at one time, break it up. For example, park your car in the back of the parking lot and walk an extra few minutes to and from work. Use the stairs instead of the elevator, and take a 5 minute walk at lunch.

If you’re overweight, losing even 5-10% of your weight can help reduce your risk of GDM. A 180 pound woman could lose 9-18 pounds and improve her health for pregnancy. The less body fat you carry, the less likely you are to develop GDM.

The foods you choose can help you lose weight, and eating a healthy, balanced diet will also decrease your risk of developing GDM. Replace sweetened beverages such as juice drinks, sweetened tea, or soda with water. Snack on fruit instead of candy or chips. Add vegetables to your lunch and dinner meals so you eat fewer calories and get nutrients. Choose foods lower in fat by grilling instead of frying chicken or fish and use lower fat dairy products.

Foods high in fiber, such as vegetables, fruit, legumes (dried beans and peas like lentils, garbanzo beans, or kidney beans), and whole grains can also decrease your risk of GDM.2 Look for the word “whole” in the first ingredient on a food label for breakfast cereal, breads, and crackers to get the most fiber.

Common Questions about Gestational Diabetes

What tests will I need to have during my pregnancy?

A glucose screening test and possibly a glucose tolerance test. If you are diagnosed with gestational diabetes, you may have to check your own blood sugar and check for urine ketones.

What is the glucose screening test?

A glucose screening test involves drawing blood to evaluate your fasting blood glucose level. You must have nothing to eat or drink for at least 8-12 hours prior to the test. A normal range for fasting blood glucose is 70-99 mg/dL. If the test comes back elevated and you have other risk factors such as a family history of diabetes or previous history of gestational diabetes it is recommended that you have a glucose tolerance test.

What is the glucose tolerance test?

There are two types of glucose tolerance tests, a 1-hour and 3-hour test. The initial 1-hour screening test measures your blood glucose one hour after consuming 50 grams of oral glucose; this may be evaluated at any time of day regardless of when you have last eaten. If your blood glucose is greater than 130 mg/dL, the next step is a 3-hour diagnostic test.
The 3-hour glucose tolerance test involves drinking 100 grams of oral glucose after fasting for 8-12 hours the night before. Blood is drawn after fasting, then at 1, 2, and 3 hour increments after consuming the oral glucose. Two or more elevated blood test results are required for a positive diagnosis of gestational diabetes.

How can gestational diabetes affect me and my baby?

Gestational diabetes develops in the second trimester of pregnancy after the baby??s body has been formed so major birth defects are not typically a result of gestational diabetes.
However, poorly controlled blood sugars can harm you and your baby. You may be at risk for high blood pressure during your pregnancy. Your baby may have macrosomia which means being larger than normal for gestational age, this can put the baby at risk for obesity and type 2 diabetes. Your baby also may have low blood sugar or be at risk for breathing problems after birth.

Will I have to have a cesarean?

The diagnosis of gestational diabetes alone is not an indication for a cesarean. However, the increased occurrence of a larger than average birth weight baby or delivery complications may increase the need for a cesarean delivery.

What can I do to control my gestational diabetes?

Follow the guidelines of your doctor to keep your blood sugar within the target range, eat a healthy diet, get regular physical activity and maintain a healthy weight throughout your pregnancy.

Why is diet so important?

Following a healthy diet can help to keep your blood sugars in the target range and prevent complications of gestational diabetes. Foods that contain carbohydrates raise the blood sugar so it is important to keep your carbohydrate intake consistent throughout the day. It is also advised to limit sugary foods and drinks while at the same time increase your intake of complex carbohydrates and fiber.

What happens after my baby is born?

After your baby is born, you will have your blood sugar checked after delivery and again 6-12 weeks later.

Will I have diabetes after my baby is born?

Gestational diabetes typically goes away after delivery however you may be at increased risk for gestational diabetes in subsequent pregnancies and for developing type 2 diabetes in the future.