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, it is important for you to be tested for gestational diabetes.
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 doesn't 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 using the oral glucose tolerance test . footnote 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. Diabetes medicines may be used to control gestational diabetes in some women.
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Frequently Asked Questions
Learning about gestational diabetes:
Living with gestational diabetes:
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.
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 level. 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 doesn't always mean that a woman has diabetes. Talk with your doctor if you have these symptoms so that you can be tested for diabetes.
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 or take diabetes medicine.
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 .
What Increases Your Risk
You have an increased chance of developing gestational diabetes if: footnote 1
- You are 35 or older when you become pregnant.
- You have had gestational diabetes before.
- You have given birth to a baby who weighed 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 had passed out (lost consciousness), or if you suddenly become very sleepy or confused. (You may have very low blood sugar, called hypoglycemia .)
Call a doctor if:
- You are sick and cannot control your blood sugar.
- You have been vomiting or have had diarrhea for more than 6 hours.
- You have a blood sugar level that stays higher than the level the doctor has set for you, for example, 17.0 mmol/L for two or more readings.
- You have blood sugar that stays lower than the level the doctor has set for you, for example, 4.0 mmol/L for two or more readings.
- You have symptoms of low blood sugar, such as:
- Feeling nervous, shaky, and weak.
- Extreme hunger and slight nausea.
- Dizziness and headache.
- Blurred vision.
Check with your doctor if:
- You often have problems with high or low blood sugar levels.
- You have questions or want to know more about gestational diabetes.
Who to see
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 using the oral glucose tolerance test. footnote 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 helps you know if your blood sugar level is within a target range.
- 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.
- 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 glycated hemoglobin) or a similar test every month during your pregnancy. The A1c test estimates your average blood sugar level over the previous 2 to 3 months.
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.
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.
You may have a follow-up glucose tolerance test 6 weeks to 6 months after your baby is born. footnote 1 If the results of this test are normal, experts recommend you get 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, it is a good idea to be tested for diabetes both before you become pregnant and early in your pregnancy.
Most women who have gestational diabetes give birth to healthy babies. 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. And 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.
Treatment for gestational diabetes during pregnancy includes:
- Eating balanced meals. 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. You will learn more about the range of weight gain that is good for you and your baby. Going on a diet during pregnancy is NOT recommended.
- Getting regular exercise. The Society of Obstetricians and Gynaecologists of Canada recommends doing 30 minutes of continuous exercise at least 4 times a week. footnote 2 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 diabetes medicine and 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 too high, you may need insulin shots or diabetes medicine.
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, 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.
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. Also, it may lower your chances of developing diabetes later in life.
- Breast-Feeding: Should I Breast-Feed My Baby?
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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).
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 may 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.
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. The Society of Obstetricians and Gynaecologists of Canada (SOGC) recommends doing 30 minutes of continuous exercise at least 4 times a week. footnote 2
If you have never exercised regularly or were not exercising before you became pregnant, talk with your doctor before you start exercising. For women who did not exercise before they became pregnant, the SOGC recommends starting with 15 minutes of continuous exercise 3 times a week. Slowly work up to 30-minute sessions 4 times a week. footnote 2 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 glucose or sucrose tablets or solution, 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.
Other aspects of your care
- As you get closer to your due date, you may have a harder time staying in your target blood sugar range. You may need to take insulin or diabetes medicine.
- 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.
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 or diabetes medicine, for example glyburide or metformin. You may also need to take insulin if your doctor thinks that your baby is getting too large.
If you need to take insulin, you will learn how to give yourself an insulin shot.
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 Places To Get Help
- Canadian Diabetes Association Clinical Practice Guidelines Expert Committee (2013). Diabetes and pregnancy section of Canadian Diabetes Association 2013 clinical practice guidelines for the prevention and management of diabetes in Canada. Canadian Journal of Diabetes, 37(Suppl 1): S168–S183. Also available online: http://guidelines.diabetes.ca.
- Davies GA, et al. (2003). Exercise in pregnancy and the postpartum period. Joint SOGC/CSEP Clinical Practice Guideline No. 129. Journal of Obstetrics and Gynaecology Canada, 25(6): 516–522.
Other Works Consulted
- American College of Obstetricians and Gynecologists (2001, reaffirmed 2010). Gestational diabetes. ACOG Practice Bulletin No. 30. Obstetrics and Gynecology, 98: 525–538.
- American College of Obstetricians and Gynecologists (2005, reaffirmed 2012). Pregestational diabetes mellitus. ACOG Practice Bulletin No. 60. Obstetrics and Gynecology, 105(3): 675–685.
- American College of Obstetricians and Gynecologists (2009). Postpartum screening for abnormal glucose tolerance in women who had gestational diabetes mellitus. ACOG Committee Opinion No. 435. Obstetrics and Gynecology, 113(6): 1419–1421.
- American College of Obstetricians and Gynecologists (2011). Screening and diagnosis of gestational diabetes mellitus. ACOG Committee Opinion No. 504. Obstetrics and Gynecology, 118(3): 751–753.
- American Diabetes Association (2015). Standards of medical care in diabetes—2015. Diabetes Care, 38(Suppl 1): S1–S93.
- Canadian Diabetes Association (2011). Testing for type 2 diabetes after gestational diabetes mellitus (GDM). Available online: http://www.diabetes.ca/diabetes-and-you/healthy-guidelines/protecting-mothers/.
- Canadian Diabetes Association Clinical Practice Guidelines Expert Committee (2013). Canadian Diabetes Association 2013 clinical practice guidelines for the prevention and management of diabetes in Canada. Canadian Journal of Diabetes, 37(Suppl 1). Also available online: http://guidelines.diabetes.ca.
- Cunningham FG, et al. (2010). Diabetes. In Williams Obstetrics, 23rd ed., pp. 1104–1125. New York: McGraw-Hill.
- U.S. Preventive Services Task Force (2014). Screening for gestational diabetes mellitus. http://www.uspreventiveservicestaskforce.org/uspstf/uspsgdm.htm. Accessed January 16, 2014.
Primary Medical Reviewer Kathleen Romito, MD - Family Medicine
Thomas M. Bailey, MD - Family Medicine
Adam Husney, MD - Family Medicine
Specialist Medical Reviewer Lois Jovanovic, MD - Endocrinology
Current as ofFebruary 11, 2015
Current as of: February 11, 2015
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