Topic Overview

What is gestational diabetes?

If your blood sugar level first becomes too high when you are pregnant, you have gestational diabetes. It usually goes back to normal after the baby is born.

High blood sugar can cause problems for you and your baby. Your baby may grow too large, which can cause problems during delivery. Your baby may also be born with low blood sugar. But with treatment, most women who have gestational diabetes are able to control their blood sugar and give birth to healthy babies.

Women who have had gestational diabetes are more likely than other women to develop type 2 diabetes later on. You may be able to prevent or reduce the severity of type 2 diabetes by staying at a healthy weight, eating healthy foods, and increasing your physical activity.

What causes gestational diabetes?

The pancreas makes a hormone called insulin. Insulin helps your body properly use and store the sugar from the food you eat. This keeps your blood sugar level in a target range. When you are pregnant, the placenta makes hormones that can make it harder for insulin to work. This is called insulin resistance.

A pregnant woman can get diabetes when her pancreas cannot make enough insulin to keep her blood sugar levels within a target range.

What are the symptoms?

Because gestational diabetes may not cause symptoms, you need to be tested for the condition. You may be surprised if your test shows a high blood sugar. It is important for you to be tested for gestational diabetes, because high blood sugar can cause problems for both you and your baby.

Sometimes a pregnant woman who has symptoms has been living with another type of diabetes without knowing it. If you have symptoms from another type of diabetes, they may include:

• Increased thirst.
• Increased urination.
• Increased hunger.
• Blurred vision.

Pregnancy causes most women to urinate more often and to feel more hungry. So having these symptoms does not always mean that a woman has diabetes. Talk with your doctor if you have these symptoms, so that you can be tested for diabetes at any time during pregnancy.

How is gestational diabetes diagnosed?

The Canadian Diabetes Association recommends that all women who are not already diagnosed with diabetes be tested for gestational diabetes between the 24th and 28th weeks of pregnancy.¹

How is it treated?

Some women with gestational diabetes can control their blood sugar level by changing the way they eat and by exercising regularly. These healthy choices can also help prevent gestational diabetes in future pregnancies and type 2 diabetes later in life.

Treatment for gestational diabetes also includes checking your blood sugar level at home and seeing your doctor regularly.

You may need to give yourself insulin shots to help control your blood sugar. This insulin adds to the insulin that your body makes.

A pill called metformin is used for type 2 diabetes that some doctors are using to treat women who have gestational diabetes.

Frequently Asked Questions

Cause

During pregnancy, an organ called the placenta develops in the uterus. The placenta connects the mother and baby and makes sure the baby has enough food and water. It also makes several hormones. Some of these hormones make it hard for insulin to do its job—controlling blood sugar—so the mother's body has to make more insulin to keep sugar levels in a safe range. Gestational diabetes develops when the organ that makes insulin, the pancreas, cannot make enough insulin to keep blood sugar levels within a target range.

Symptoms

Because gestational diabetes does not cause symptoms, you need to be tested for the condition. This is usually done between the 24th and 28th weeks of pregnancy. You may be surprised if your test shows a high blood sugar. It is important for you to be tested for gestational diabetes, because high blood sugar can cause problems for both you and your baby.

Sometimes, a pregnant woman has been living with diabetes without knowing it. If you have symptoms from diabetes, they may include:

• Increased thirst.
• Increased urination.
• Increased hunger.
• Blurred vision.

Pregnancy causes most women to urinate more often and to feel more hungry, so having these symptoms does not always mean that a woman has diabetes. Talk with your doctor if you have these symptoms, so that you can be tested for diabetes.

What Happens

Most women find out they have gestational diabetes after being tested between the 24th and 28th weeks of their pregnancy. After you know you have gestational diabetes, you will need to make certain changes in the way you eat and how often you exercise to help keep your blood sugar level within a target range. As you get farther along in your pregnancy, your body will continue to make more and more hormones. This can make it harder and harder to control your blood sugar. If it is not possible to control your blood sugar with food and exercise, you may also need to give yourself shots of insulin. Some doctors are using a pill called metformin to treat women who have gestational diabetes.

Diabetes: Giving Yourself an Insulin Shot

Just because you have diabetes does not mean that your baby will have diabetes. Most women who have gestational diabetes give birth to healthy babies. If you are able to keep your blood sugar level within a target range, your chances of having problems during pregnancy or birth are the same as if you didn't have gestational diabetes.

Sometimes a mother or her baby has problems because of high blood sugar. These problems include:

• High blood pressure in the mother caused by pre-eclampsia.
• A baby that grows too large. If a developing baby (fetus) receives too much sugar, the sugar can turn into fat, causing the baby to grow larger than normal. A large baby can be injured during vaginal birth and may need to be delivered surgically (C-section).
• After the baby is born, the baby's blood sugar level may drop too low, and he or she may need to be given extra sugar.
• Babies can also develop other treatable problems after birth, including low blood calcium levels, high bilirubin levels, and too many red blood cells.

Most of the time, gestational diabetes goes away after a baby is born. But if you have had gestational diabetes, you have a greater chance of having it in a future pregnancy and of developing type 2 diabetes. Up to 30 out of 100 women who develop gestational diabetes will develop diabetes within 15 years.²

Each year, up to 20 out of 100 pregnant women in Canada will develop gestational diabetes.²

What Increases Your Risk

You have an increased chance of developing gestational diabetes if:¹

• You are 35 or older when you become pregnant.
• You have had gestational diabetes before.
• You have given birth to a large baby (generally more than 4 kg (9 lb).
• You are obese (your body mass index[BMI] is 30 or higher).
• You are a member of a racial group or ethnic group that has a high risk of diabetes, such as First Nations, Hispanic, South Asian, Asian, or African.
• You have polycystic ovary syndrome.
• You have a dark skin rash called acanthosis nigricans on the back of your neck or in folds on your body.
• You take corticosteroid medicine.

When to Call a Doctor

Call 911 or other emergency services right away if:

• You passed out (lost consciousness) or you suddenly become very sleepy or confused. You may have low blood sugar.

  Learn about emergency care for low blood sugar.

• You are sleepy, confused, or breathing very fast, or if your breath smells fruity. You may have very high blood sugar.

Call a doctor right away if:

• Your blood sugar is 17.0 mmol/L or higher (or it is higher than the level your doctor has set for you).

Call a doctor if you:

• Are sick and having trouble controlling your blood sugar.
• Have had vomiting or diarrhea for more than 6 hours.
• Often have problems with high or low blood sugar levels.
• Have trouble knowing when your blood sugar is low.
• Have questions or want to know more about gestational diabetes.

Who to see

Your family doctor, general practitioner, or obstetrician can diagnose and treat gestational diabetes. You may be referred to a doctor who specializes in high-risk pregnancies (perinatologist).

After you are diagnosed with gestational diabetes, you may be referred to other health professionals who can help you understand what gestational diabetes means. These may include:

• A certified diabetes educator (CDE). A CDE is a registered nurse, registered dietitian, doctor, pharmacist, or other health professional who has training and experience in caring for people who have diabetes. A CDE can help you understand how to take care of yourself and help you adjust to living with gestational diabetes.
• A registered dietitian. All women who have gestational diabetes need to see a registered dietitian for help choosing the best foods. Follow-up visits with a dietitian are helpful if you need to change your eating habits.

Examinations and Tests

Experts debate whether all pregnant women need to be tested for gestational diabetes. But most doctors routinely test all pregnant women who are in their care. The Canadian Diabetes Association recommends that all women who are not already diagnosed with diabetes be tested for gestational diabetes between the 24th and 28th weeks of pregnancy.¹

Tests during pregnancy

If you have gestational diabetes, your doctor will check your blood pressure at every visit. You will also have certain tests throughout your pregnancy to check your and your baby's health. These tests include:

• Home blood sugar monitoring. Testing your blood sugar at home every day helps you know if your blood sugar level is within a target range. You may need to give yourself insulin shots to help control your blood sugar. Some doctors are using a pill called metformin to treat women who have gestational diabetes.
• Fetal ultrasound. This test may be used to estimate the age, weight, and health of your baby. The ultrasound test also can measure the size of your baby's head and abdomen. This measurement along with other information can be used to help your doctor decide on your care. If your doctor thinks your baby is bigger than normal for his or her gestational age and your blood sugar is high, then your doctor may decide you need to start taking insulin or diabetes pills. Taking insulin when you have gestational diabetes will help keep your blood sugar in a target range, which can stop your baby from growing too big. Keep in mind that ultrasounds cannot always accurately estimate how much your baby weighs or whether there are other problems.
• Non-stress test. A non-stress test can help you know how well your baby is doing by checking your baby's heartbeat in response to movement.

Some doctors may recommend you have a hemoglobin A1c (glycosylated hemoglobin) or a similar test every month during your pregnancy. The A1c test estimates your average blood sugar level over the previous weeks to months.

Gestational Diabetes: Checking Your Blood Sugar

Tests during labour and delivery

During labour and delivery, you and your baby will be monitored very closely.

• Fetal heart monitoring is used to see how well your baby is doing while you are in labour.
• Blood sugar tests are done regularly to make sure your blood sugar level is within a target range.

Tests after delivery

After your baby is born, your blood sugar level will be checked several times. Your baby's blood sugar level will also be checked several times within the first few hours after birth.

Follow-up

Even though your gestational diabetes will probably go away after your baby is born, you are at risk for gestational diabetes again and for type 2 diabetes later in life. Up to 30 out of 100 women who develop gestational diabetes will develop diabetes within 15 years.²

You will have a follow-up glucose tolerance test 6 weeks to 6 months after your baby is born.¹ If the results of this test are normal, you will still need to be tested for type 2 diabetes at least every 3 years. Even if your sugar level is normal, you are at increased risk of developing diabetes in the future. Eating healthy foods and getting regular exercise can help prevent type 2 diabetes.

If you want to get pregnant again, you should be tested for diabetes both before you become pregnant and early in your pregnancy.

Treatment Overview

Finding out that you have gestational diabetes can be scary. It can be reassuring to know that most women who have gestational diabetes give birth to healthy babies and that you are the most important person in promoting a healthy pregnancy.

Treatment for gestational diabetes involves making healthy choices. Most women who make changes in the way that they eat and how often they exercise are able to keep their blood sugar level within a target range. Controlling your blood sugar is the key to preventing problems during pregnancy or birth.

You, your doctor, and other health professionals will work together to develop a treatment plan just for you. You do not need to eat strange or special foods. But you may need to change what, when, and how much you eat. You also do not need to start a fancy exercise program or join an expensive gym. Walking several times a week can really help your blood sugar.

The lifestyle changes you make now will help you have a healthy pregnancy and prevent diabetes in the future. As you start making these changes, you will learn more about your body and how it reacts to food and exercise. You may also notice that you feel better and have more energy.

During pregnancy

Treatment for gestational diabetes during pregnancy includes:

• Eating a balanced diet. After you find out that you have gestational diabetes, you will meet with a registered dietitian to create a healthy eating plan. You will learn how to limit the amount of carbohydrate you eat as a way to control your blood sugar. You may also be asked to write down everything you eat and to keep track of your weight. In general, it is not a good idea to diet while you are pregnant. Talk to your doctor about how much weight you should gain during pregnancy. If you are overweight or obese, your doctor may recommend that you eat less and gain less weight than other pregnant women. Overweight or obese women have a higher risk for high blood pressure and a blood circulation problem called pre-eclampsia.
• Getting regular exercise. Regular, moderate exercise during pregnancy helps your body use insulin better and helps control your blood sugar level. If you have never exercised regularly or were not exercising before you became pregnant, talk with your doctor before you start exercising. Low-impact activities, such as walking or swimming, are especially good for pregnant women. You may also want to try special exercise classes for pregnant women.
• Checking blood sugar levels. An important part of treating gestational diabetes is checking your blood sugar level at home. Every day, you will do a home blood sugar test one or more times. It may be overwhelming to test your blood sugar so often. But knowing that your level is within a target range can help put your mind at ease. Talk to your doctor about how often to test your blood sugar.
• Monitoring fetal growth and well-being. Your doctor may want you to monitor fetal movements called kick counts and let him or her know if you think your baby is moving less than usual. You may also have fetal ultrasounds to see how well your baby is growing. You may have a non-stress test to check how well your baby's heart responds to movement.
• Getting regular medical checkups. Having gestational diabetes means regular visits to your doctor. At these visits, your doctor will check your blood pressure and test a sample of your urine. You will also discuss your blood sugar levels, what you have been eating, how much you have been exercising, and how much weight you have gained.
• Taking insulin shots. The first way to treat gestational diabetes is by changing the way you eat and exercising regularly. If your blood sugar levels are still too high after changing the way you eat and exercising regularly, you may need insulin shots. Insulin can help lower your blood sugar level without harming your baby. Some doctors are using a pill called metformin to treat women who have gestational diabetes.

Most doctors will recommend that you breast-feed, if possible, for the health benefits for you and your baby. For example, breast-feeding can help keep your child at a healthy weight, which may reduce his or her chances of developing diabetes. It provides antibodies to strengthen your baby's immune system, and it lowers your baby's risk for many types of infections. And it may lower your chances of developing diabetes later in life.

Breast-Feeding: Should I Breast-Feed My Baby?

Breast-Feeding: Planning Ahead

During labour and delivery

Most women who have gestational diabetes are able to have their babies vaginally. Just because you have gestational diabetes does not mean that you will need to have a caesarean section (C-section).

Because a baby that has grown too large can be difficult to deliver safely, your doctor will do fetal ultrasounds to check the size of your baby. If your doctor thinks that your baby is in danger of being too large, he or she may decide to induce labour or do a C-section.

During labour and delivery, you and your baby are monitored closely. This includes:

• Checking your blood sugar level regularly. If your level gets too high, you may be given small amounts of insulin through a vein (intravenously, or IV). If your level drops too low, you may be given IV fluid that contains glucose.
• Checking your baby's heart rate and how well your baby's heart responds to movement. Fetal heart monitoring helps your doctor know how your baby is doing during labour. If the baby is large or does not seem to be doing well, you may need to have a C-section to deliver your baby.

After delivery

After delivery, you and your baby still need to be monitored closely.

• For the first few hours, your blood sugar level may be tested every hour. Usually blood sugar levels quickly return to normal.
• Your baby's blood sugar level will also be watched. If your blood sugar levels were high during pregnancy, your baby's body will make extra insulin for several hours after birth. This extra insulin may cause your baby's blood sugar to drop too low (hypoglycemia). If your baby's blood sugar level drops too low, he or she may need extra sugar, such as a sugar water drink or glucose given intravenously.
• Your baby's blood may also be checked for low calcium, high bilirubin, and extra red blood cells.

What to think about

Most of the time, the blood sugar levels of women who have gestational diabetes return to normal in a few hours or days after delivery.

If you have had gestational diabetes, you are at risk for having it again in a future pregnancy. You are also at risk of type 2 diabetes, a permanent type of diabetes. The healthy choices and changes you made during your pregnancy, if continued, will help you prevent diabetes in the future. If you are worried about type 2 diabetes in yourself or in your child, talk to your doctor about your concerns.

Prevention

In some women, gestational diabetes cannot be prevented. But you may be able to lower your chance of getting gestational diabetes by staying at a healthy weight and not gaining too much weight during pregnancy. Regular exercise can also help keep your blood sugar level within a target range and prevent gestational diabetes.

If you have had gestational diabetes, you are at risk for having it again in a future pregnancy. You are also at risk for type 2 diabetes, a permanent type of diabetes. One of the best ways to prevent developing gestational diabetes again is to stay at a healthy weight.

If you have had gestational diabetes, avoid medicines that increase insulin resistance, such as nicotinic acid and glucocorticoid medicines (for example, prednisone and dexamethasone).

Home Treatment

You are the most important person in determining whether you will have a healthy pregnancy. Gestational diabetes, like any form of diabetes, cannot be successfully treated with medicines alone.

Your doctor, diabetes educator, registered dietitian, and other health professionals can help you learn how to care for yourself and protect your baby from problems. If you learn as much as you can about gestational diabetes, you will have the knowledge you need to have a healthy pregnancy. As you understand how food and exercise affect your blood sugar, you can better control your blood sugar level and help prevent problems from gestational diabetes.

Home treatment for gestational diabetes includes changing the way you eat, exercising regularly, and checking your blood sugar.

Eating healthy foods

Changing what, when, and how much you eat can help keep your blood sugar level in a target range. After you are diagnosed with gestational diabetes, you will meet with a registered dietitian to decide on an individualized healthy eating plan. Your dietitian may ask you to write down everything you eat and to keep track of your weight. He or she will also teach you how to count carbohydrate in order to spread carbohydrate throughout the day. For more information, see:

Gestational Diabetes: Counting Carbs.

Getting regular exercise

Regular, moderate exercise during pregnancy helps your body use insulin better, which helps control your blood sugar level. Often, exercising and eating well can treat gestational diabetes.

If you have never exercised regularly or were not exercising before you became pregnant, talk with your doctor before you start exercising. Exercise that does not place too much stress on your lower body—such as using an arm ergometer, a machine that just works your arm muscles; or riding a recumbent bicycle, a type of bike with a seat that looks like a chair—are especially good for pregnant women. You may also want to try special exercise classes for pregnant women or other low-impact activities such as swimming or walking.

If exercise and changing the way you eat keep your blood sugar within a target range, you will not need to take diabetes medicine. If you need to take insulin, make sure you have a quick-sugar food, such as 3 to 4 glucose tablets or 3 pieces of hard candy, with you when you exercise in case you have symptoms of low blood sugar. Symptoms of low blood sugar include sweating, blurred vision, and confusion. If you think that your blood sugar is low, stop exercising, check your blood sugar level, and eat the snack.

Checking your blood sugar

An important part of treating gestational diabetes is checking your blood sugar level at home. Every day, you will do a home blood sugar test one or more times. It may be overwhelming to test your blood sugar so often. But knowing that your level is within a target range can help put your mind at ease. Talk to your doctor about how often to test your blood sugar.

Gestational Diabetes: Checking Your Blood Sugar

Other aspects of your care

• If changing the way you eat and exercising do not control your blood sugar level, you may need to take daily insulin shots.
• If you were overweight before you became pregnant, do not try to lose weight while you are pregnant. Ask your doctor how much weight you should gain during your pregnancy.
• Your doctor may have you check kick counts and let him or her know if you think your baby has been moving less than usual.
• If you take insulin, it can cause your blood sugar to drop below the target range. Even though very low blood sugar is rare in women who have gestational diabetes, it is important to know the symptoms of low blood sugar and have glucose or sucrose tablets or solution or quick-sugar foods with you at all times. For more information, see:

Gestational Diabetes: Dealing With Low Blood Sugar.

Medications

Most women can treat gestational diabetes by changing the way they eat and exercising more often. If these changes do not keep your blood sugar level within a target range, you may need to take insulin. You may also need to take insulin if your doctor thinks that your baby is getting too large.

If you need to take insulin, your doctor will teach you how to give yourself an insulin shot.

Gestational Diabetes: Giving Yourself Insulin Shots.

Some doctors are using a pill called metformin to treat women who have gestational diabetes.

What to think about

Insulin is the primary medicine used to treat gestational diabetes. Insulin is only used if you cannot control your blood sugar level by eating well and exercising regularly.

How much insulin you need depends on how much you weigh and on how close you are to your due date. Some women need more insulin as they get closer to their delivery date, because the placenta makes more and more hormones that make it harder and harder for insulin to do its job. In rare cases, a woman with gestational diabetes has to stay in the hospital for a short time to get her blood sugar level within a target range.

Other Treatment

All pregnant women need to take prenatal vitamins. If you want to take other types of vitamins, talk with your doctor. Do not take more of any vitamin than would be found in the approved prenatal vitamins.