Exercise as it relates to Disease/Physical activity interventions to improve Gestational Diabetes Mellitus and pregnancy outcomes
Please Note: This article has been written entirely in the context of one article, and as a result only relates to exercise as a treatment.
Gestational Diabetes Mellitus
Gestational Diabetes Mellitus is a form of diabetes that occurs only during pregnancy. It is the most common metabolic condition experienced due to pregnancy and one of the most common pregnancy complications. It is very similar to type II diabetes as it is characterised by an inability to cope with the extra demand for insulin that results during pregnancy, which causes abnormally high blood glucose levels. In a normal pregnancy, the pregnant mother's blood glucose levels will elevate, a mechanism designed to ensure adequate energy is supplied to the developing foetus. As a result, a pregnant mother will experience a large increase in insulin resistance (200-250%), and therefore a 2-4 fold increase in insulin production. For reasons that are still relatively unknown, some women experience a breakdown in this pathway and do not experience the expected increase in insulin production, and a diabetic state occurs.
Gestational diabetes substantially increases the risk of adverse health effects for both the mother and the child including:
- Increased risk of macrosomia
- low birth weight
- higher chance of caesarean deliveries and the associated health implications
- increased risk of type II diabetes later in life for both the mother and the child
- perinatal morbidity
There is no cure for gestational diabetes, however it can be controlled. To manage it, excess glucose must be removed from the blood which can be achieved by:
- altering the diet to include fewer carbohydrates (grains and sugars)
- increasing physical activity
- pharmaceutical interventions
- insulin injections
Exercise as a Treatment
Until recently, using exercise as a treatment strategy was thought to be risky for the mother and foetus. However there is evidence to suggest that supervised exercise intervention can be an effective treatment option. The evidence provided was published by Reuben Barakat and his colleagues from the University of Madrid, and the University of Granada in Spain. It was published in the British Journal of Sports Medicine, in January 2013. This can be considered a very strong article. It is a randomised control study, one of the strongest forms of research, and it is published in a reputable medical journal. It also had an adherence to exercise rate of >95%, which is a very good completion rate for this type of research.
The authors followed 210 pregnant women who had been diagnosed with Gestational Diabetes. The vast majority of these women led sedentary lifestyles and were untrained prior to falling pregnant. Participants completed a resistance based training session, 3 times per week up until the end of the third trimester. Each session lasted 50–55 minutes and involved a light aerobic warm-up and resistance based exercises including:
Activities were targeted at the whole body, and participants were instructed to work between 10-12 on a 20 point RPE (rate of perceived exertion) scale (“fairly light” to “somewhat hard”, 4-6 on a 10 point scale). The women who completed the exercise were compared to 218 women who received “normal care”, but no exercise intervention.
The women in the exercise group showed improvements in:
- Oral Glucose Tolerance Test (OGTT) score (~6% lower)
- 38% less Caesarean deliveries
- 58% less Macrosomic births
- approximately 12% less maternal weight gain
There also appears to be long term benefits for the child. There is evidence that the children of mothers with gestational diabetes are at higher risk of obesity and the related health concerns such as metabolic disease and cardiovascular disease. Exercise during pregnancy appears to neutralise some of these risks, although the mechanism for this reduction is at this time unknown.
Criticisms and Concerns
Although this article is strong, it is not without faults. The research base is quite narrow, it only looked at one form of exercise, moderate intensity resistance training. There was no comparison to other common forms of diabetes management, such as pharmaceutical interventions, or specialised diet plans. Therefore there may be more effective management solutions, there may be more effective types of exercise, or exercise could be combined with other treatments for optimum efficacy. More comprehensive research should be undertaken in an attempt to discover the most effective type, frequency and intensity of exercise, and how exercise influences other forms of treatment, in either a positive or a negative way.
According to the authors, it is clear that physical activity can be used to minimise the effects of gestational diabetes, and it should be considered by all health professionals working with these women. It can reduce the risks of complications affecting the mother, the safety of the pregnancy, and the long term wellbeing of the child. Women should be made aware of the potential health benefits of physical activity through education campaigns, and planned and supervised exercise programs should be offered whenever possible.
If professionally planned and supervised exercise programs are unavailable, women need to be aware of the potential risks of exercising while pregnant.
The American College of Sports Medicine, f Sports Medicine Australia, and The Royal College of Obstetricians and Gynaecologists from the United Kingdom have all created guidelines for exercising safely while pregnant. A brief summary of these guidelines are:
- It is safe to continue any form of exercise completed prior to falling pregnant.
- It is safe and beneficial to start a new exercise program.
- Exercise intensity should be kept at ‘moderate’, as according to the RPE scale.
- Weight bearing and aerobic exercises are both safe.
- As the pregnancy progresses, changes in the centre of gravity and laxity of the ligaments caused by hormonal changes will increase the risk of falls and joint injuries - Avoid unstable activities such as ballistic weight lifting, and jumping.
- Avoid contact activities such as judo, boxing, kickboxing, or contact sports.
- Exercise should be ceased, and medical help sought if any of the following is experienced:
- Uterine contractions
- Vaginal bleeding
- Amniotic fluid discharge
- Sudden swelling of the hands, face, and ankles
- Back or pelvic pain
- Decreased foetal movements
- Temperature regulation may be impaired, creating the possibility of overheating. Avoid exercise in hot environments.
- Avoid exercises performed while lying on the back. It may impinge the blood flow to the foetus.
- Seek medical advice prior to starting an exercise program, all pregnancies are different, you may be at elevated risk of illness or injury.
- Barakat R, Pelaez M, Lopez C, Lucia A, Ruiz JR. Exercise during pregnancy and gestational diabetes-related adverse effects: A randomised controlled trial. Br J Sports Med 2013;47(10):630-636.
- Golbidi S, Laher I. Potential mechanisms of exercise in gestational diabetes. Journal of Nutrition and Metabolism 2013;2013:1-16.
- Blackburn S. Maternal, Fetal & Neonatal Physiology: A clinical Perspective. 4th ed. 3251 Riverport Lane, Maryland Heights: Saunders; 2013.
- Morris E. CAESAREAN SECTION. Royal College of Obstetricians and Gynaecologists 2009 October, 2009;7(1).
- Sibbald B, Roland M. Understanding Controlled Trials: Why Are Randomised Controlled Trials Important? BMJ: British Medical Journal 1998;316(7126):201-201.
- Burguet A. Long-term outcome in children of mothers with gestational diabetes. Diabetes and Metabolism 2010;36(6):682-694.
- Raul Artal, M.D., James F. Clapp, III, M.D., and Daniel V. Vigil, M.D., FACSM. Exercise During Pregnancy. Available at: https://www.acsm.org/docs/current-comments/exerciseduringpregnancy.pdf. Accessed 09/29, 2015.
- Sports Medicine Australia. Exercise in Pregnancy. Available at: http://sma.org.au/wp-content/uploads/2009/10/WIS-ExPreg.pdf, 2015.
- Royal College of Obstetricians and Gynaecologists. Recreational Exercise and Pregnancy: Information for you. 2006; Available at: https://www.rcog.org.uk/globalassets/documents/patients/patient-information-leaflets/pregnancy/recreational-exercise-and-pregnancy.pdf. Accessed 09/29, 2015.