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Your gestational diabetes questions, answered

If you’re anxious about gestational diabetes, you are not alone. Dr. Lorraine Lipscombe addresses commonly asked questions and misconceptions.

pregnant woman talking to doctor

Pregnancy is punctuated by milestones, appointments and ultrasounds. Weeks 24 to 28 mark the transition to your third trimester and are likely when you’ll book your glucose challenge test (GCT).
The GCT goes something like this: you’ll be given a 50 g bottle of super sweet beverage to drink up. One hour later, you’ll have your blood drawn and then be sent on your way. If you fail the screening, you may have to go back for a three-hour glucose tolerance test to see how your body responds to glucose over time. If the answer is “not well,” then you’ll likely be diagnosed with gestational diabetes mellitus (GDM).
GDM is a temporary condition that affects pregnant women in the second half of pregnancy. Around six to 10 percent of pregnant women will have GDM, making it one of the most common complications in pregnancy. It usually resolves after delivery, but one in five will develop Type 2 diabetes within 10 years of having GDM.
A GDM diagnosis is accompanied by a lot of questions, misconceptions and negative emotions. Dr. Lorraine Lipscombe, an endocrinologist and director of the division of endocrinology at Women’s College Hospital, sets the record straight.
Is every pregnant woman screened for gestational diabetes mellitus (GDM)?
Canadian guidelines recommend that all pregnant women get screened for GDM because its risk factors are common, making it difficult to isolate women who may be more at risk than others. Many of its risk factors are the same as Type 2 diabetes and are generally present before a woman becomes pregnant. These include weight, ethnicity [South Asian and Indigenous women], family history and inactivity. Other risk factors are pregnancy-specific, including the age of gestation [older than 35], excessive weight gain during pregnancy, carrying multiples and having a history of GDM.
If a woman has many of these risk factors, she’ll be screened earlier to make sure she doesn’t have Type 2 diabetes that wasn’t diagnosed before pregnancy.
Are there any signs that you may have gestational diabetes?
The signs of high blood glucose, including frequent urination and tiredness, are often non-specific and common during pregnancy, which is why screening is essential.
Does what you eat before the test affect your results?
It has not been shown that what you eat leading up to the glucose challenge test will affect your results. Having said that, if you eat, say, a slice of chocolate cake immediately before drinking that 50 g drink, it may affect your glucose response, which can necessitate follow-up screening.
How do eating habits early in early pregnancy affect your results?
What you eat during your pregnancy has not been shown to affect the likelihood of getting gestational diabetes. What has been shown to affect GDM is excess weight gain in pregnancy [more than the recommended amounts of 25 to 35 pounds for those with a BMI of 18 to 25; 11 to 20 pounds for a BMI between 30 and 40; eight to 10 pounds for those with a BMI greater than 40]. Studies have shown that a woman who gains more weight than recommended will have an increased risk of gestational diabetes.
What happens if you fail the glucose test?
If your glucose is above the threshold for the first test, there are two possibilities. If it is very high, then you likely won’t need to do a second set of testing – you’ll be diagnosed on the spot. If it’s only modestly high, then you’ll do the three-step test, which involves fasting and checking what happens before the drink, one hour after the drink and two hours after the drink.
How will gestational diabetes potentially affect your pregnancy?
While pregnancy is supposed to be a happy and hopeful time, a GDM diagnosis has implications for your health as well as the health of your offspring. The extra appointments, plus checking your blood sugar multiple times a day and watching what you eat make the experience difficult overall. Your health-care team is there to support you and make sure your pregnancy is healthy, especially if you’re meeting the blood-sugar guidelines.
You may also experience some anxiety about what this means for your health. We know that one in five women with gestational diabetes will develop Type 2 diabetes within 10 years. This can make women feel nervous or disappointed about what their future holds.
There is a silver lining – once you’ve been identified as having a higher risk of Type 2 diabetes, you’ll receive a lot of education around how you can lower that risk, as well as tips for long-term self-care including advice on healthy eating, scheduling regular physical activity and managing stress. Through personal glucose monitoring multiple times a day, you’ll also see real-time feedback around how food and exercise directly affects your blood sugar – it can be a positive, enlightening experience.
How will gestational diabetes affect my appointment schedule?
Your medical visits will increase during this time. In Canada, it’s recommended that all women diagnosed with gestational diabetes be referred to a diabetes specialist or endocrinologist, in addition to their primary prenatal-care physician. You’ll have to schedule extra appointments, including additional tests and ultrasounds, which can be more time-consuming. Many health-care teams are trying to combine diabetes and prenatal appointments to make it more convenient.
How long does gestational diabetes last?
For most women with gestational diabetes, around 70 percent, diabetes will go away soon after delivery. However, one in five will be diagnosed with Type 2 diabetes within 10 years. It’s important for women who have had gestational diabetes to continue living a healthy lifestyle to prevent Type 2 diabetes. Women should also have their blood sugar checked by their primary care physician every one to three years and if planning another pregnancy.
What does gestational diabetes mean for the birth of my baby?
If you’ve been identified as having high blood sugar, the risk is that the baby will grow too big, which presents an increased risk for complications during birth, including early labour, C-section delivery, shoulder dystocia, which happens when there’s difficulty delivering a large baby through the pelvis. If the condition is carefully managed, there’s no reason for you to worry about a complicated birth.
Many new moms are in survival mode with a newborn. How are they supposed to manage healthy lifestyle modifications on top of it all?
Once the baby is born and gestational diabetes goes away, maintaining a healthy lifestyle may become a second priority behind competing demands as a mother. It can be especially challenging for new moms to focus on their health while caring for an infant. The support of your family and friends can be helpful, but if you aren’t getting the support you need, talk to your diabetes health-care team. They may be able to help you find a support group for women in a similar situation.
Our ADAPT-M [Avoiding Diabetes After Pregnancy Trial in Moms] study is aimed at helping women adopt a healthier lifestyle. Those participating in the study receive individual counselling and frequent follow-up calls from health coaches to stay on track. Human nature is to put ourselves second when there’s someone relying on us, and our program teaches women to make their health a priority.
Dr. Lorraine Lipscombe, endocrinologist and director of the division of endocrinology, Women’s College Hospital
This information is provided by Women's College Hospital and is not intended to replace the medical advice of your doctor or healthcare provider. Please consult your healthcare provider for advice about a specific medical condition. This document was last reviewed on: November 25, 2019.
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  • Women's College Hospital