• Jen Bennett RD CDE

The DL on GDM - Gestational Diabetes!

Do you have questions about gestational diabetes? Maybe you’re pregnant right now and are wondering about how to get tested. Maybe you’ve done the gestational diabetes test and have been diagnosed with gestational diabetes. Either way, most women feel worried or stressed about gestational diabetes and we are here to set your mind at ease!


Gestational Diabetes or “GDM” is a type of diabetes (high blood sugars) that is diagnosed in pregnancy, in women who did not have diabetes before getting preggo! It’s usually diagnosed in the second or third trimester and between 3%-20% of pregnant women get diagnosed.

To break it down even further, it’s good to understand the role of certain hormones. Insulin is a hormone that helps the body regulate the level of sugar in the blood. There are many hormones that increase throughout pregnancy and make it hard for the body to produce enough insulin. This leads to higher than normal sugar levels and therefore, a diagnosis of GDM. After the baby is born though, and hormones go back to normal, the diabetes usually goes away.


There are risks for mom and baby if gestational diabetes is left untreated.

For mom, the problems include high blood pressure (or “preeclamsia”) and an increased risk of c-section (due to baby growing too large). Having GDM also increases the chances that GDM will occur in future pregnancies and/or that the mother will develop type 2 diabetes later in life. There are many ways to reduce the risk of type 2 diabetes that a dietitian can help with!

For baby, the problems include, baby growing too large (this is called “macrosomia”), birth traumas such as “shoulder dystocia” (which means the shoulder(s) gets stuck during delivery), and low blood sugars after birth, which can be dangerous.

However, saying this, mothers with GDM and their babies have access to lots of support which lowers these risks and leads to happy, healthy pregnancies, babies and outcomes! So fear not!


So how does one go about getting checked for GDM? Well, here in Canada, every woman can get screened for GDM between 24-28 weeks. You book an appointment at the lab and they give you an orange coloured drink that has 50 grams of sugar in it. Some people hate the taste, some people (like Jen!), don’t really mind it too much. You have to drink the beverage within 5 minutes, hang out for an hour, and then the lab draws some blood to see how much sugar is left in your blood. Here’s what the results mean:

<7.8 mmol/L would indicate that your blood sugars were within a normal range and you DO NOT have gestational diabetes.

7.8 mmol/L - 11.0 mmol/L would indicate that you need to do one more test called the Oral Glucose Tolerance Test (or an OGTT). It’s basically the same thing except you have to fast beforehand, drink another orange drink with 75 grams of sugar and get blood drawn before your drink (fasting sugar), and at 1 hour and 2 hours post-drink! If any of these three results come back higher than target, you would be diagnosed with GDM.

>11.1 mmol/L would indicate that you have gestational diabetes and a second test is not required.


If you are diagnosed with gestational diabetes, the cornerstone of management is nutrition therapy and physical activity (as able). Most women should be referred to a “diabetes-in-pregnancy” clinic and/or a registered dietitian. A dietitian can help you understand your nutrition requirements in pregnancy, considerations for blood sugar control and important weight gain guidelines for the duration of your pregnancy. They can also explain what types of activity benefit blood sugars, when to move your body and for how long.

In some situations, pregnancy hormones prevail over nutrition and lifestyle intervention, despite a person’s best effort, and medication may be required to lower blood sugars in order to keep mom and baby safe. This is a discussion you can have with your dietitian, prenatal care provider, and endocrinologist.


We’d like to get these common misconceptions out of the way and clear some things up!

Myth 1: Avoid carbohydrates if you get diagnosed with gestational diabetes.

Don’t do this!!! Carbohydrates are the best source of energy for you and your baby. Yes, carbohydrates have a direct effect on your blood sugars, but a dietitian can help you choose carbohydrate foods that are better for your blood sugars and which foods to pair them with to help stabilize your sugars throughout the day (to avoid spikes).


Myth 2: Mothers in smaller bodies do not get diagnosed with gestational diabetes.

There are several risk factors that increase a persons chance of developing GDM. These include age, being from a high-risk population group (African, Arab, Asian, Hispanic, Indigenous, or South Asian), having had GDM in a previous pregnancy or previously delivering a larger baby (>4 kg), having a parent or sibling with type 2 diabetes, or previously being diagnosed with polycystic ovarian syndrome (PCOS).

However, mothers can still be diagnosed with GDM, even without any of these risk factors. Remember, pregnancy hormones play a large role and women who are in smaller bodies, previously healthy and few or no risk factors can also be diagnosed.


Myth 3: You will need insulin no matter what.

Simply not true! Many many women can manage their GDM with diet and lifestyle without needing insulin injections or any oral medications. Sometimes it’s just a matter of learning which foods to eat more of and how best to incorporate activity!



We hope this information was helpful and cleared up a few confusing bits about gestational diabetes. As always, if you have more questions, book a free call with one of our registered dietitians.

References: Diabetes of Canada

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