Dr. Tanya Lee, H.BSc, ND

What is it?

Gestational diabetes mellitus (GDM) is a condition that is screened and diagnosed in the 2nd trimester, effecting about 5-10% of all pregnancies.1,2 This condition is rapidly increasing in North America, partly due rising trends of overweight/obese individuals, which translate to rising numbers of overweight and obese women of childbearing age, However there are other risk factors other than body weight that contribute to the development of GDM.

What can happen if I have it?

Having GDM affects both mother and baby – higher than average birth weights in children born to mothers with GDM increase the risk for complications during vaginal deliveries, such as shoulder dystocia, and therefore are typically delivered via C-section. There is also risk of neonatal jaundice, newborn hypoglycemia at birth, as well as risk of early labour, stillbirth, miscarriage and development of high blood pressure.1,2   Women with GDM and their children are at higher risk for developing type 2 diabetes later in life.1 These factors are why it’s important to recognize that the prevention of GDM is essential to a planned pregnancy and to consult with your healthcare professional to see if you’re at risk.

Who is likely get develop it?

There are a number of risk factors that have been recognized in the development of GDM – women who have a higher body-mass-index have a higher risk for developing GD. Ethnicity also plays a role – women of Hispanic, Native American, African and Asian decent have higher risk of developing GD.1

What can I do to prevent it?

There are a number of studies that outline factors that can help prevent the onset of gestational diabetes. It has been found that lifestyle factors such as implementing physical activity and dietary changes can reduce risk of GDM by 18%, but these factors have a greater effect if started before 15 weeks of pregnancy.3

  • Diet has been found to play an extremely important role in the prevention of GDM. Applying dietary strategies before and even early on in pregnancy have shown to have a significant part in preventing GDM.3 A diet full of nutrients from whole foods, such as fruits, vegetables, legumes, whole grains, good fats (such as olive oil), high fibre, and the reduction in red and processed meats and sodium, as outlined in the Mediterranean diet and the DASH diets, has been found to reduce the risk of GDM.4 High consumption of red meat for iron can increase risk of GDM than those who predominantly consume non-red meat sources of iron.2
    Also, it is important to recognize that staying away from foods higher on the Glycemic Index (GI) (as in foods that quickly and drastic spike blood sugars after eating), such as white starches (white flour foods – bagels, white breads), can dramatically reduce your risk of developing GDM.2 Whole grains such as oats, legumes, brown rice, are lower on the GI and are encouraged.
  • Regular physical activity before and during pregnancy may decrease risk of GDM by 28%, compared to those who do not exercise.5 Anywhere between lower intensity exercises, such as yoga and flexibility exercises, to higher intensity exercises such as aerobics, jogging, and strength training are safe and beneficial to pregnancy.6 Contact sports should be avoided. There are currently no set exercise guidelines specific to GDM, however the combination between resistance training and aerobic exercises better manage blood glucose levels, and should be performed at a minimum of 30-60 minutes 3 times a week.6
  • A couple of nutritional supplements have been studied for the prevention of GDM, and should be recommended by a trained healthcare professional before use. Vitamin D deficiency is associated with poor glucose control and has been found to improve outcomes when supplemented to correct the deficiency.2
    Myo-inositol is a nutrient found in both animals and plants sources of foods as well as naturally made by the liver. This supplement, when introduced in the first trimester of pregnancy, can also reduce the incidence of GDM in high risk women.2,7

The research on GDM prevention is promising, however there is no set regime on how to properly implement these strategies to prevent the onset of GDM. A recent study found that an outlined specific dietary and physical activity regime from trained professionals had a lower risk of developing GDM than those who received standard care.8 It is clear that screening and treatment for vitamin D deficiency, as well as implementing a whole-food diet (such as Mediterranean or DASH diets), low glycemic index foods, and regular aerobic exercise and resistance training are essential to the prevention of GDM.

HCM HSDr. Tanya Lee, N.D. received her Honours Bachelor of Science degree in Biochemistry and Biomedical Sciences from McMaster University, and was trained as a Naturopathic Doctor at the Canadian College of Naturopathic Medicine.  Dr Lee practices full-time between two clinics located in Toronto and Milton Ontario and has been voted Milton’s favourite Naturopath in 2013 and 2014.   Her primary care practice focuses on family medicine, treating a wide variety of conditions such as hormonal (endocrine) disorders, fertility, digestive problems, cardiovascular disease, diabetes, insomnia and fatigue.  She has a special interest in the treatment of autoimmune diseases, paediatric and perinatal health.  Tanya offers her clinical knowledge to a number of publications, including the Natural Path.


  • Kampmann U et. al Gestational diabetes: A clinical update. World J Diabetes. 2015 Jul 25;6(8):1065-72
  • Castorino K. et. al. A review of prevention strategies for gestational diabetes: is there a missing X-factor? Minerva Endocrinol. 2016 Dec;41(4):433-44
  • Song C et. al. Lifestyle intervention can reduce the risk of gestational diabetes: a meta-analysis of randomized controlled trials. Obes Rev. 2016 Oct;17(10):960-9
  • Izadi V et. al Adherence to the DASH and Mediterranean diets is associated with decreased risk for gestational diabetes mellitus. 2016 Oct;32(10):1092-6.
  • Russo LM et. al. Physical activity interventions in pregnancy and risk of gestational diabetes mellitus: a systematic review and meta-analysis. Obstet Gynecol. 2015 Mar;125(3):576-82
  • Padayachee C, Coombes JS. Exercise guidelines for gestational diabetes mellitus. World J Diabetes. 2015 Jul 25;6(8):1033-44
  • Celentano C et. al. Myo-Inositol Supplementation to Prevent Gestational Diabetes Mellitus. Curr Diab Rep. 2016 Mar;16(3):30.
  • Koivusalo SB et. al. Gestational Diabetes Mellitus Can Be Prevented by Lifestyle Intervention: The Finnish Gestational Diabetes Prevention Study (RADIEL): A Randomized Controlled Trial. Diabetes Care. 2016 Jan;39(1):24-30.
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