What is Gestational Diabetes?
Gestational diabetes (GD) is a type of diabetes that affects between 3-20% of pregnant women.1 Pregnant women with GD are unable to produce enough insulin to regulate the body’s blood sugar levels.2 Insulin, is a hormone that allows blood sugar to enter the cells of the body and the body uses the sugar for energy. During pregnancy, many pregnant women produce more insulin because there are changes in the body that make the mother more resistant to her own insulin. Many women are able to compensate and produce more insulin to keep their blood sugar levels normal. However, some pregnant women are unable to produce enough insulin and their blood sugar rises, a condition known as gestational diabetes. Elevated blood sugar levels may cause health problems for mother and baby.3
In most cases, women who experience gestational diabetes will develop it between the second and third trimesters and may find that the diabetes goes away after giving birth.1,3
Contributing Risk Factors and Causes of Gestational Diabetes
There are several risk factors that may help predict whether a woman will develop gestational diabetes:
- A family history of diabetes2
- A previous pregnancy where you were diagnosed with gestational diabetes or gave birth to a very large baby2
- Being 35 years old or older2
- Aboriginal, African, Hispanic, South Asian, or Asian ethnic background2
- Obesity or having a BMI that was greater than 30 before you became pregnant4
- Use of corticosteroids (drugs for treating arthritis) during pregnancy2
Studies of indigenous Canadian peoples have indicated that women in First Nations communities are significantly more likely to develop gestational diabetes than non-Aboriginal women.4 In one study, the rate varies from 3.7% in non-Aboriginal women to 8% to 18% in Aboriginal women, especially those who are of First Nations decent.5
Women can reduce their risk of developing GD with lifestyle changes such as eating a healthy diet and staying active before and during their pregnancy.2,3
Gestational Diabetes Symptoms
Pregnant women who have gestational diabetes may not even know they have it until they are tested for it. GD typically doesn’t have any symptoms, in some cases, some pregnant women may notice they are thirstier than usual or having to use the bathroom more frequently.4 These signs of gestational diabetes are often mild and may even be attributed to simply being part of pregnancy.
Gestational Diabetes Testing
Pregnant women are offered a test to screen for gestational diabetes between week 24 and 28 of their pregnancy—typically when GD would develop.3 If your medical history indicates you’re at risk for GD, the test may be offered earlier than 24 weeks and then repeated later in the pregnancy to ensure that both baby and mother are healthy.
The screening test is often referred to as a glucose challenge, and its goal is to learn how well your body handles sugars while you’re pregnant.2 Your doctor will give you a sugary beverage to drink. After an hour, your blood sugar will be tested. If it’s at a normal level, you will not require any further testing, as you will not be considered at risk for gestational diabetes.2
If your blood sugar is very high (>11.1mmol/L) after the glucose challenge, you will be diagnosed with gestational diabetes. If your blood sugar is high (7.8-11.0mmol/L) after the glucose challenge, you will have a second test called the 2-hour glucose tolerance test. While the first glucose challenge can be done at any time of day and does not require any fasting, the second test is done in the morning and does require you to abstain from eating or drinking beforehand.2 This second test mimics the first; you’ll drink a glucose drink and your blood sugar will be tested an hour later and then another hour later. If your blood sugar level remains elevated above a certain number after both tests, you have tested positive for gestational diabetes.2
Risks of Having Gestational Diabetes
Even though gestational diabetes is common, it does come with risks to both the mother and the baby:
- Elevated blood sugar may cause preeclampsia in the mother, which is high blood pressure during pregnancy.1
- A mother with GD may deliver a very large baby with a high birth weight, which may increase the need for a caesarian section delivery.1,5
- Infants whose mothers have gestational diabetes are at risk for low blood sugar levels after birth and jaundice.5
While many women will find that their blood sugar levels return to normal after their babies are born, about 50% of women with GD will develop type 2 diabetes sometime in their life.3 Babies born to mothers with gestational diabetes are at risk of developing diabetes as well.5
Managing Gestational Diabetes
While learning that you have gestational diabetes can be upsetting, it doesn’t mean you have to stop living your life or enjoying your pregnancy. There’s a lot you can do to manage your GD. Make sure you attend all your prenatal appointments to track your baby’s growth and development and talk to your doctor about a GD treatment plan that’s personalized for you:
- You should regularly check your blood sugar to ensure that your glucose levels are in a range that is healthy for you and your baby.
- Ask your doctor to refer you to a registered dietitian who can provide guidance on eating a healthy diet.3
- Staying active and exercising while pregnant is important. It can lower your blood sugar and make you less sensitive to insulin so that your body won’t need as much.3 Talk to your doctor about how to exercise safely while pregnant.
While many women who have gestational diabetes can manage it with a healthy diet and exercise, lifestyle changes may not be enough. About 30% of women who develop GD will need to take insulin to help the manage their blood sugar.5 Insulin is safe to take during pregnancy and pregnant women will need to continue to monitor their diet, stay active, and check their glucose levels.6