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Gestational diabetes mellitus

February 9, 2021

Gestational diabetes mellitus - featured image

Dietitian Philippa Bredenkamp from Mindful Eating Dietitian Consultancy shares insightful information on Gestational Diabetes Mellitus. Gestational Diabetes Mellitus (GDM) is a condition in which a woman without diabetes develops high blood sugar levels or glucose intolerance which is onset or first recognised during pregnancy.

Philippa forms part of our network of allied health professionals at our Busamed Modderfontein Private Hospital.

Briefly, what is gestational diabetes?

Gestational diabetes is a form of diabetes that develops for the first-time during pregnancy. The reason why this happens is that your body cannot produce enough insulin to handle the effects of a growing baby and changing hormone levels or the insulin that your body does make does not work properly. Insulin helps your body control the level of glucose (sugar) in your blood. If your body cannot produce enough insulin or the insulin does not work effectively, your blood sugar levels will rise.

What are the symptoms?

This is one of the issues with Gestational Diabetes Mellitus (GDM), as you often do not have any noticeable symptoms and many women may in fact be shocked to find out that they even have gestational diabetes. Therefore, according to the American College of Obstetricians and Gynaecologists, pregnant woman should be screened for GDM between 24 and 28 weeks of pregnancy as often a high blood glucose level from a blood test is the only sign of GDM.

Is gestational diabetes serious?

GDM should be taken seriously to prevent it from becoming serious. If treated properly there are minimal complications and the outcomes are actually similar to non-GDM pregnancy. However, if not treated properly the high level of blood glucose will pass through the placenta to the baby, which will lead to a large baby, together with a host of other complications. Untreated GDM can also lead to a greater likelihood of developing high blood pressure during the pregnancy.

If diabetes is prevalent in my family, am I more likely to get it during pregnancy?

Definitely. Having a family history of diabetes is a well-known risk factor for GDM.

Does having gestational diabetes mean I will be diabetic for the rest of my life?

Not necessarily as in most cases GDM goes away after the baby is born. However, having GDM does increase your risk of developing Type 2 diabetes later in life as approximately 50% of women who have had GDM will develop type 2 diabetes within 10-20 years. If you have another pregnancy, there is a very high chance of developing GDM again. Eating well and being active can reduce your risk of developing type 2 diabetes in the future. Depending on your risk factors, you will also need to be checked for type 2 diabetes again every 1 to 3 years.

How is gestational diabetes treated?

The best way to ensure your that your blood glucose levels are controlled are with a well calculated menu, physical activity (if your doctor has said it is safe for you to exercise), strict monitoring of your blood glucose levels and as a very last resort medication.

At our practice we are able to successfully control our client’s blood sugar levels by calculating an individualized menu as well as asking them to keep a food-blood glucose diary. That way we can see what food causes issues with their blood glucose. It is very important to ensure you have a dietitian helping you manage your menu and blood sugar readings, as I have seen each person is so different. For example, I can have one client who can have ½ a cup of brown rice and their blood glucose remains within normal range, while another can have that exact same ½ cup brown rice, yet it will increase their glucose.

Here are some very simple guidelines to follow if you are experiencing high blood sugar levels during your pregnancy and are yet to consult with a medical professional:


  • Have small regular meals.
  • Move your breakfast to morning snack time and your morning snack to breakfast time (in the early morning, due to your hormones, you are not able to handle a lot of food without your blood glucose spiking – thus a smaller meal first thing in the morning helps to prevent this spike).
  • Have a small amount of complex carbohydrate at each meal (It is VERY important not to have no carbohydrates while pregnant as the ketones that your body makes when you deprive it of carbohydrates pose a threat to foetal development).
  • Try to have a protein or fat at each meal to reduce the GI of the meal.
  • Avoid all refined sugars (sweets, chocolate, biscuits, desserts, cold-drinks, fruit juices).

Blood Glucose Testing

When testing your blood glucose, during GDM you should always aim for it to be below 8mmol/L.


The American College of Obstetricians and Gynaecologists recommends 30 minutes of moderate-intensity aerobic exercise at least 5 days a week or a minimum of 150 minutes per week. Research shows that nutrition plus physical activity may be more effective than diet alone in controlling blood glucose levels in GDM, and I have certainly seen this in practice.
What are the effects on my baby if I have gestational diabetes?

If one’s blood glucose levels are well controlled the effects should be minimal. However if the GDM is uncontrolled, the risk to the baby can include being too large in size, having low blood sugar after birth which would likely lead to admission into the NICU as well as increased risk of being overweight and/or developing type 2 diabetes later on in life.

Will gestational diabetes affect the type of birth I will have?

If the mothers blood glucose has being uncontrolled and baby has become too large, this will make it difficult to have a normal vaginal delivery.

What advice can you give expectant mothers who have been diagnosed with GDM?

The other most important piece of information I would want moms with GDM to know is that your blood glucose can become worse as the pregnancy goes a long. This happens because your hormone levels are increasing, which makes the insulin resistance worse, which leads to higher glucose levels. Get yourself to a dietitian who works with GDM to give you the knowledge you need.

Our hospitals that offer maternity units include:
Busamed Hillcrest Private Hospital
Busamed Harrismith Private Hospital
Busamed Modderfontein Private Hospital

If you have any health-related concerns, please consult with your doctor or seek appropriate medical advice. The above information does not serve as an online diagnosis, and we do not accept responsibility for loss or damaged suffered by the reader as result of the above.

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