What is gestational diabetes?
During pregnancy, some women develop high blood sugar levels. This condition is known as gestational diabetes mellitus (GDM) or gestational diabetes. Gestational diabetes typically develops between the 24th and 28th weeks of pregnancy.
It’s estimated to occur in 2 to 10 percent of pregnancies in the United States, according to the Centers for Disease Control and Prevention.
If you develop gestational diabetes while pregnant, it does not mean that you had diabetes before or will do so later in your pregnancy. However, gestational diabetes increases your risk of developing type 2 diabetes in the future.
If managed poorly, it can increase your child’s risk of developing diabetes and increase the risk of complications for you and your baby during pregnancy and delivery.
What are the symptoms of gestational diabetes?
It is rare for gestational diabetes to cause symptoms. If you experience symptoms, they will likely be mild. These may include:
- blurred vision
- extreme thirst
- extreme need to pee
What causes gestational diabetes?
The exact cause of gestational diabetes is unknown, but hormones likely play a role. When you’re pregnant, your body produces greater amounts of hormones, including:
- human placental lactogen (hPL)
- hormones that increase insulin resistance
These hormones affect your placenta and help you maintain your pregnancy. Over time, the amount of these hormones in your body increases. They can start to make your body resistant to insulin, the hormone that regulates your blood sugar.
Insulin helps the glucose in your blood flow into cells where it is used for energy. During pregnancy, your body naturally becomes slightly insulin resistant so there is more glucose in your bloodstream to pass to the baby. If insulin resistance becomes too strong, your blood sugar levels may rise abnormally. This can cause gestational diabetes.
Who is at risk for gestational diabetes?
The risk of developing gestational diabetes is higher if:
- women over the age of 25 who became pregnant
- those with high blood pressure
- have a family history of diabetes
- they were overweight before getting pregnant
- gaining more than your normal weight while pregnant
- expecting multiple babies
- has previously given birth to a baby weighing more than 9 kilograms
- have had gestational diabetes in the past
- have had an unexplained miscarriage or stillbirth
- has been on glucocorticoids
- have polycystic ovary syndrome (PCOS), acanthosis nigricans, or other conditions associated with insulin resistance
- African, Native American, Asian, Pacific Islander, or Hispanic
How is gestational diabetes diagnosed?
The American Diabetes Association (ADA) encourages doctors to regularly screen pregnant women for signs of gestational diabetes. If you do not have a known history of diabetes and normal blood sugar levels at the start of your pregnancy, your doctor will screen you for gestational diabetes when you are 24 to 28 weeks pregnant.
Some doctors may start with a glucose test. No preparation is required for this test.
You will drink a glucose solution. An hour later you will get a blood test. If your blood sugar level is high, your doctor may do a three-hour oral glucose tolerance test. This is considered a two-stage test.
Some doctors skip the glucose test altogether and only do a two-hour glucose tolerance test. This is considered a one-step test.
one step test
- Your doctor will start by testing your fasting blood sugar level.
- They will ask you to drink a solution containing 75 grams (g) of carbohydrates.
- They’ll test your blood sugar level again in an hour and two hours.
- fasting blood sugar level greater than or equal to 92 milligrams per deciliter (mg/dL)
- An hourly blood glucose level greater than or equal to 180 mg/dL
- Two-hour blood glucose level greater than or equal to 153 mg/dL
- You will not need to fast for the two-step test.
- They will ask you to drink a solution containing 50 g of sugar.
- They test your blood sugar an hour later.
If your blood sugar level is greater than or equal to 130 mg/dL or 140 mg/dL at this point, they’ll perform a second follow-up test on a different day. The threshold for determining this is decided by your doctor.
- During the second test, your doctor will start by testing your fasting blood sugar level.
- They will ask you to drink a solution containing 100 g of sugar.
- They test your blood sugar after one, two, and three hours.
They will diagnose you with gestational diabetes if you have at least two of the following values:
- fasting blood sugar level greater than or equal to 95 mg/dL or 105 mg/dL
- An hourly blood glucose level greater than or equal to 180 mg/dL or 190 mg/dL
- Two-hour blood glucose level greater than or equal to 155 mg/dL or 165 mg/dL
- Three-hour blood glucose level greater than or equal to 140 mg/dL or 145 mg/dL
Should I also be worried about type 2 diabetes?
The ADA also encourages doctors to screen women for type 2 diabetes early in pregnancy. If you have risk factors for type 2 diabetes, your doctor will test you for the condition at your first prenatal visit.
These risk factors include:
- be overweight
- to be sedentary
- having low levels of good (HDL) cholesterol in your blood
- having high levels of triglycerides in your blood
- Having a family history of diabetes
- have a past history of gestational diabetes, prediabetes, or symptoms of insulin resistance
- Having previously given birth to a baby weighing more than 9 pounds
- African, Native American, Asian, Pacific Islander, or Hispanic
Are there different forms of gestational diabetes?
Gestational diabetes is divided into two classes.
Class A1 is used to describe gestational diabetes that can only be controlled by diet. A2. People with second-class gestational diabetes will need insulin or oral medications to control their condition.
How is gestational diabetes treated?
If you’ve been diagnosed with gestational diabetes, your treatment plan will depend on your blood sugar levels throughout the day.
In most cases, your doctor will recommend testing your blood sugar before and after meals and managing your condition by eating healthy and exercising regularly.
In some cases, they may also add insulin injections if needed. According to the Mayo Clinic, only 10 to 20 percent of women with gestational diabetes need insulin to control their blood sugar.
If your doctor recommends monitoring your blood sugar levels, they may provide you with a special glucose monitor.
They can also give you insulin injections until you give birth. Ask your doctor to properly time your insulin injections and exercise in relation to your meals to avoid low blood sugar.
Your doctor can also tell you what to do if your blood sugar levels are too low or consistently higher than they should be.
What should I eat if I have gestational diabetes?
A balanced diet is key to proper management of gestational diabetes. In particular, women with gestational diabetes should pay special attention to their carbohydrate, protein and fat intake.
Eating regularly – every two hours – often – can help control your blood sugar levels.
Carbs should only make up 40 to 50 percent of your calories each day. Aim to get 20 to 25 percent of your calories from protein and 25 to 35 percent of your calories from fat.
Pregnant women should aim for 120 to 195 g of carbohydrates daily. This should be spread out as about 3 meals and 2 meals a day as a snack. Proper separation of carbohydrate-rich foods will help prevent blood sugar spikes.
Your doctor will help you determine how many carbohydrates you should consume each day. They may also recommend that you see a registered dietitian to assist with meal plans.
Healthy carb options include:
- whole grains
- brown rice
- beans, peas, lentils, and other legumes
- starchy vegetables
- low sugar fruits
Pregnant women should eat at least 60 g of protein each day. Good sources of protein include lean meats and poultry, fish and tofu.
Healthy fats to include in your diet include unsalted nuts, seeds, olive oil and avocado. If you have gestational diabetes, get more tips on what to eat – and avoid – here.
What complications are associated with gestational diabetes?
If your gestational diabetes is poorly managed, your blood sugar levels may remain higher than they should throughout your pregnancy. This can cause complications and affect your child’s health. For example, when your baby is born, he may have:
- high birth weight
- difficulty breathing
- low blood sugar
- shoulder dystocia, which causes the shoulders to get stuck in the birth canal during labor
There may also be a higher risk of developing diabetes later in life. That’s why it’s so important to take steps to manage your gestational diabetes by following your doctor’s recommended treatment plan.
What is the outlook for gestational diabetes?
After giving birth, your blood sugar should return to normal. But developing gestational diabetes increases your risk of type 2 diabetes later in life. Ask your doctor how you can reduce your risk of developing these conditions and related complications.
Can gestational diabetes be prevented?
It is not possible to completely prevent gestational diabetes. However, adopting healthy habits can reduce your chances of developing the condition.
If you are pregnant and have one of the risk factors for gestational diabetes, try eating a healthy diet and exercising regularly. Even light activities such as walking can be beneficial.
If you are planning to become pregnant in the near future and you are overweight, one of the best things you can do is work with your doctor to lose weight. Even losing a small amount of weight can help reduce your risk of gestational diabetes.
American Diabetes Association. (2018). 2. Classification and Diagnosis of Diabetes: Standards of Medical Care in Diabetes-2018.
American Diabetes Association. (2018). Standards of medical care in diabetes 2018.