Gestational Diabetes

Pregnant belly with two arms around it - pregnant woman and her partner holding her belly from behind - Gestational Diabetes

Have you heard of Gestational Diabetes before? Gestational Diabetes (GDM) can be simplified to diabetes diagnosed during pregnancy. It’s more common than you may think and the risk of developing GDM depends on many factors.


What is Gestational Diabetes (GDM)?

GDM can be defined as having high blood sugar (glucose) levels during pregnancy (3).  Unlike type-1 diabetes GDM and type-2 diabetes develop over time. The difference between GDM and type-2 diabetes is that GDM develops during pregnancy.


Symptoms of Gestational Diabetes:

Other than the established risk factors, high blood glucose levels are the only sign of GDM (3). Individuals who experience obvious symptoms of high blood sugar during pregnancy may have undiagnosed type-2 diabetes that developed before pregnancy (3).


Causes of Gestational Diabetes:

The hormones produced by the placenta during pregnancy decrease insulin activity in your body; this is called insulin resistance (4). Insulin is a hormone that helps control the amount of glucose in your blood. If insulin activity decreases, your pancreas needs to produce extra insulin to keep your blood glucose levels within their normal range (4).

 However, if your pancreas can’t produce extra insulin, your blood glucose levels will rise. High blood glucose leads to the development of diabetes during pregnancy. Additionally, there are other risk factors that increase the chances of developing GDM.


Risk Factors of Gestational Diabetes:

    • Age during pregnancy: 35+ years (5)
    • High risk groups (Indigenous, Hispanic, African, Asian, Arab, South Asian)(5)
    • Corticosteroid medication use (ex: cortisone, prednisone, hydrocortisone, etc.) Which treat conditions such as allergies, asthma, psoriasis, IBD, eczema, etc. (2).
    • Pre-diabetes (5)
    • Previously diagnosed with GDM (5)
    • Given birth to a baby over 4kg (9lbs) (5)
    • Have a parent or sibling with type-2 diabetes (5)
    • Polycystic Ovarian Syndrome (PCOS) (5)
    • Acanthosis Nigricans (dark patches of skin in body folds) (5)
    • Pregnancy with twins; this can increase glucose intolerance (3)

How is Gestational Diabetes Diagnosed?

You may be wondering: if there aren’t any symptoms how will I know if I have diabetes during my pregnancy? All pregnant women should be screened at 24-28 weeks pregnant, and women at high risk should be screened at less than 20 weeks (5). The test given is called the glucose challenge screening but is otherwise known as the oral glucose test. In Canada there are 2 versions: the 2 step (preferred) or the 1 step (alternative). 


2 Step (non-fasting):

This test is done non-fasted, meaning you can eat before the exam if desired (1). When you get there:

    • You are given a 50g glucose (sugar) load (drink)(1).
    • 1 hour later your blood glucose is measured (1). 
      • If the value comes back below a certain level no more testing is required (1).
      • If the value comes back above a certain level gestational diabetes is diagnosed (1).
    • However, if the value is within a certain range your blood glucose level will be measured 3 more times:
      • First, blood glucose is measured after fasting. Then you are given a 75g glucose (sugar) load (1).
      • Blood glucose will be measured two more times: 1 hour after the glucose load, then 2 hours after the glucose load (1).
    • Gestational diabetes is diagnosed if any of the last 3 blood glucose values meet or exceed specific values. 

    1 Step (Fasting):

    This test is done after fasting. 

      • Blood glucose is measured before the glucose load. Then you are given a 75g glucose (sugar) load (1). 
      • Blood glucose will be measured two more times: 1 hour after the glucose load, then 2 hours after the glucose load (1).
        • Gestational diabetes is diagnosed if any of the 3 blood glucose values meet or exceed specific values (1). 

      How to reduce Your Risk of Developing GDM

      Did you know that 3-20% of pregnant women develop diabetes during pregnancy? There are things you can do to minimize your risk of developing GDM – or if you have GDM there are ways to maintain it. What’s most important is that you work with your primary health care provider and a dietitian.


      Managing Gestational Diabetes

      It’s important that GDM is managed because it can increase the risk of complications during pregnancy and birth. In addition, there is an increased risk of developing type-2 diabetes after giving birth. Management of GDM can reduce these risks. So, how can it be managed?

        • Eating low glycemic foods such as fruit, whole grains, and oatmeal (4).
        • Increasing fibre during pregnancy
          • Fiber slows carbohydrate absorption which means there won’t be a spike in your blood glucose
        • Being physically active on a regular basis (4)
        • Monitoring blood glucose (4)
        • Taking medication (4)

      Monitoring blood glucose and taking medication isn’t always necessary. Your primary healthcare provider will know what’s right for you. They will also tell you how much activity and what kind of activity is appropriate. 

      Working With a Dietitian

      In addition to your primary healthcare provider, a dietitian can help you maintain or reduce your risk of developing GDM. Dietitians can work with you and your primary health care provider to establish a personal dietary plan that is based on your individual needs.


      Unmanaged GDM

      Unmanaged GDM can lead to health problems during and after your pregnancy that can affect both you and your baby. It can:

        • Increase your risk for developing type-2 diabetes after pregnancy (5).
        • Increase the risk of your baby being over 4kg (9lbs). This can cause serious complications during birth (5).
        • Lead to an increased risk of your baby developing type-2 diabetes, and being born with malformations (5).
        • Increase the risk of miscarriage and stillbirth (5).


      Final Notes from The Nest

      Gestational Diabetes should be taken seriously. While there may be no symptoms associated with Gestational Diabetes (GDM) all pregnant women are given the oral glucose test to determine their risk. GDM can be prevented or maintained through diet and exercise, however, working closely with your primary health care provider and dietitian is strongly encouraged. It is suggested to work with a dietitian to get the best nutrition advice for your individual health needs. Additionally, you will have the best chance at decreasing your risk for developing GDM or maintaining your GDM if you have proper dietary advice throughout your pregnancy.

        Article Written by Spencer Wentzell

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        1. Berger, H., Gagnon, R., & Sermer, M. (2016). Diabetes in pregnancy. Journal of Obstetrics and Gynaecology Canada, 38(7). 
        2.  Dresden , D. (2020, March 18). Corticosteroids: Types, side effects, and how they work. Medical News Today. Retrieved March 21, 2022, from 
        3. Freeze, C., & Royall, D. (2018, July 6). Gestational diabetes. Gestational Diabetes Background. Retrieved March 21, 2022, from 
        4. Gestational diabetes. National Diabetes Services Scheme – An Australian Government Initiative . (n.d.). Retrieved March 21, 2022, from 
        5.  Managing your blood sugar . Diabetes Canada. (n.d.). Retrieved March 21, 2022, from