Gestational Diabetes

Gestational Diabetes Mellitus (GDM) is a type of diabetes that occurs during the second or third trimester of  pregnancy. It occurs when pregnancy hormones make it harder for your body to use insulin effectively. Insulin is a hormone that helps regulate the amount of glucose (sugar) in your blood. In most cases individuals with gestational diabetes did not have diabetes before their pregnancy; however after giving birth, the diabetes usually goes away.

During pregnancy, your body needs to produce more insulin to keep blood sugar levels within a healthy range. If your body cannot make enough insulin, your blood glucose levels rise, leading to gestational diabetes. Elevated glucose levels may also result in glucose being detected in your urine during prenatal visits.

When blood sugar levels remain high for a prolonged period, they can affect both you and your baby. Babies may grow larger than expected, which can increase the likelihood of a cesarean birth and/or complications during labour and birth.  After birth, babies born to individuals with GDM may experience low blood sugar and often require closer monitoring and support.

Pregnant individuals who are diagnosed with GDM are at higher risk of developing Type 2 diabetes in their future.  You can reduce the risk of developing GDM by managing your weight, eating healthily and keeping active before and during pregnancy.

Symptoms for GDM may include increased thirst, urination and hunger along with blurred vision. 

However, if you are having any of these symptoms it does not mean you have diabetes. Speak with your care provider if you have any of these symptoms so that you can decide together whether you should be tested for GDM. Your health care provider may offer you a glucose tolerance test between 24-28 weeks of pregnancy. This test involves fasting, taking a blood sample, drinking a high glucose (sugary) drink, and then having a blood sample taken again to assess your body's ability to handle glucose. The result of this test helps to diagnose GDM.

If you're pregnant and have diabetes or have been diagnosed with gestational diabetes, please check out this patient conversation guide published by Ontario Health to help you have informed conversations with your health care provider.

For more information about risk factors for gestational diabetes, screening processes, and management, please see the links below.

• Canadian Diabetes Association - Gestational diabetes: what it means for you and your baby

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• HealthyFamiliesBC - Special health concerns during pregnancy

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• HealthLinkBC - Gestational diabetes: causes, symptoms, diagnosis and treatment

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• Pregnancy Info - Glucose testing - screening for gestational Diabetes

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• The MotHERS Podcast - Diabetes in Pregnancy (featuring Dr. Laura Gaudet)

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• Diabetes.ca - Gestational diabetes

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• Centers for Disease Control and Prevention - Gestational Diabetes and Pregnancy

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• Ontario Health - Diabetes in Pregnancy Quality Standard