Management of Gestational Diabetes Through Exercise and Nutrition
A report released by the CDC in 2015 revealed that nearly half (47%) of all pregnant women gain more than recommended during pregnancy (1). The study’s co-author, Dr. Andrea Sharma, an epidemiologist with the U.S. Centers for Disease Control and Prevention’s Maternal and Infant Health Branch stated, “This is a concern because gaining too much weight has health consequences for both mothers and infants(2)”. Gestational diabetes mellitus (GDM) is one of these concerns.
GDM complicates a significant number of pregnancies and unfortunately, studies demonstrate an overall upward trend (3). Possible adverse infant outcomes include macrosomia, hypogylcemia, arrhythmia, hypocalcemia, jaundice and birth trauma (6). In the most extreme cases, it continues to be a cause of perinatal and maternal morbidity and mortality (3).
The consequences of GDM do not end with labor and delivery. Women diagnosed with GDM are at a higher risk for developing diabetes mellitus (DM) in the future. These women are also more likely to exhibit characteristics of insulin resistance syndrome which is associated with cardiovascular disease.
Their offspring, unfortunately, have greater health risks as well. Children born to mothers with GDM are more likely to become obese later in life and have an abnormal glucose tolerance in adolescence or early adulthood in comparison to offspring of normoglycemic women (6).
There are certain risk factors that make some women more susceptible to GDM; including advanced maternal age, family history of type 2 diabetes mellitus, beginning pregnancy overweight, as well as glucose intolerance during pregnancy (6). In addition, recent research has shown that excessive weight gain (in early pregnancy especially), may contribute to increased risk of GDM. Women who gain greater than the recommended weight gain during pregnancy tend to have trouble losing it postpartum. In fact, it is estimated that these women retain twice as much weight following labor and delivery as women who gained within the recommended guidelines (6). As indicated, GDM and excessive weight gain combined set women up for a myriad of health concerns both pre- and postnatally.
A 2005 article published in the journal Clinical Diabetes states, “Approximately 4% of pregnant women in the United States have diabetes. Eighty-eight percent have GDM (450,000 women per year), and the remaining 12% have either type 1 (12,000) or type 2 (50,000)” (5). While these numbers are concerning, this can be viewed as an amazing opportunity for education, intervention and improved health outcomes if the necessary support is in place. Women can benefit immensely from education and non-medical management (in the form of diet and exercise) whenever possible. With the goal of improving pregnancy outcomes, the short and long-term health of mom and baby and the health of future generations, we must recognize the importance of early detection, education and health promotion. Pregnancy Fitness Educators have the capacity to provide eduction and safe fitness instruction thereby, affecting change.
To counteract this cycle of poor health outcomes for both mom and baby, physical activity (PA) and nutrition should be considered as first line defense. A 2011 study “Exercise during pregnancy improves maternal glucose screen at 24–28 weeks: a randomized controlled trial” demonstrated that a moderate prenatal PA program improves levels of glucose tolerance (6). Researchers studied 83 healthy pregnant women and assigned each randomly into a control or exercise group. The exercising women participated in a 35–45 minute session three times per week (two land aerobic sessions, one aquatic session). This program was conducted from the beginning of pregnancy (weeks 6–9) through until the end of the third trimester (weeks 38–39). As the 50 g maternal glucose screen (50 g MGS) has become a standard component of detecting GDM, it was utilized as part of the data collection (6).
The researchers found significant differences between the study groups on the 50 g MGS and values corresponding to the Exercise Group (EG) were better than the Control Group (CG). Additionally, there were no differences in maternal weight gain and no cases of GDM in the EG as opposed to an increase in weight and three cases of GDM in the CG (6). Synthesizing this data as well as that from other similar studies, the researchers concluded that a “moderate exercise programme during pregnancy improves the level of glucose tolerance” (6). Based on the slight difference in maternal weight gain and cases of GDM, they also concluded that exercise could be considered a protective factor. While promising, they recognized the need for more random control trials (RCTs).
In another study, “Prevention of Gestational Diabetes: Feasibility Issues for an Exercise Intervention in Obese Pregnant Women,” researchers set out to determine if individualized exercise programs could positively impact the health of obese pregnant women and prevent GDM. This RCT followed 50 obese pregnant women, 25 women participated in an individualized exercise program, while the other 25 received routine care. Using the “Pregnancy Physical Activity Questionnaire”, the average weekly expenditure of kilocalories was assessed.
The exercising group utilized individualized programs with an energy expenditure goal of 900 kcal/week; whereas the control group received routine obstetric care. At each of the times mentioned (baseline and 20, 28, and 36 weeks’ gestation), fasting insulin, glucose and HOMA-IR were assessed. Additionally, a 2-h 75-g oral glucose tolerance test was performed at baseline and 28 weeks (4). Overall, the study found that there was some evidence of efficacy, as there was increased physical activity in the exercising group at some time points during pregnancy (28 and 36 weeks in particular).
In addition, women in the exercising group achieved adequate activity at 20 weeks and at 28 weeks were considerably more likely to achieve greater than 900 kcal/week of exercise-based activity. The data revealed no difference in HOMA-IR between the intervention and control groups. At 28 weeks, fasting glucose was lower in the exercising group than the control group, and at 36 weeks, insulin was lower in the exercising group (4).
Researchers concluded that exercise alone might not be sufficient during pregnancy to affect insulin resistance. They also wondered about the sensitivity of HOMA-IR as an assessment tool to measure the impact of exercise on insulin resistance. Ultimately, they hypothesized that a combined dietary and exercise intervention might have a greater impact on insulin resistance and therefore, a greater chance at preventing GDM (4).
A 2011 article, “Gestational diabetes mellitus: Non-insulin management” in the Indian Journal of Endocrinology and Metabolism suggests that medical nutrition therapy (MNT) is the cornerstone of therapy for woman with GDM (3). The article stresses the importance of quality nutrition throughout pregnancy for optimal growth and development of baby. According to the authors, to manage GDM with MNT, calories and nutrients must be manipulated and restricted strategically in order to achieve optimal glucose levels. They stress the importance of MNT design by a dietician to best reach not only glycemic goals, but nutrition and weight goals as well. This is a challenge as the dietician simultaneously needs to ensure adequate nutrition for not only the woman, but the developing fetus (as stressed previously).
According to the article, “trials have proven that almost up to 80– 90% cases of GDM can be effectively managed with MNT (3). Unfortunately, “there is very little information available to allow evidence-based recommendations regarding specific nutritional approaches such as total calories and nutrient distribution to the management of GDM” (3).
This form of therapy is a self-management therapy and requires significant involvement from the care team to prove successful including initial education and ongoing support to assist the woman in making lifestyle modifications. Assessment data must be collected throughout treatment to measure weight, glucose, to review food records and make modifications as needed. It is vital that the woman feels supported throughout this treatment and pregnancy to increase adherence and ultimately, health for herself and baby. The study suggests that pharmacological treatment be utilized if NMT proves ineffective.
Based on the information presented here, it is clear that both exercise and nutrition play important roles in the prevention and management of GDM. However, more research is needed. More RCTs are needed to discern the best physical activity prescription and more information is needed to provide evidence-based recommendations regarding specific nutritional approaches for management of GDM. Greater access and dissemination of evidence based information will help to further this cause and influence recommendations for the management of GDM.
Despite guidelines, the importance of an individualized plan for each woman cannot be underestimated, should be considered and incorporated when creating a treatment plan. In addition, the woman’s motivation will impact the success of whatever approach is taken — PA, MNT, pharmacological methods or a combination. The provider’s role and involvement cannot be underestimated as women will require ongoing education, monitoring, support and follow-up.
With the goal of improving pregnancy outcomes, the short and long-term health of mom and baby and the health of future generations, we must synthesize all of this information and utilize it well. Providers have the opportunity to promote health, provide education, to detect and early and treat holistically in an effort to reduce GDM and the associated poor health outcomes. Pregnancy Fitness Educators have the capacity to provide eduction, support and safe fitness instruction which can be an important component of most treatment programs.
1. Deputy, N.P., Sharma, A. J., Kim, S.Y. “Gestational weight gain — United States 2012 and 2013.” Center for Disease Control and Prevention: Morbidity and Mortality Report (64) 43. 2015: 1215–1220.
2. Haelle, T. “Many women gain too much weight while pregnant, study finds.” Health Day: News for Healthier Living (2015). Web 23 Mar 2015.
3. Magon, Navneet, and V. Seshiah. “Gestational diabetes mellitus: non-insulin management.” Indian Journal of Endocrinology and Metabolism 15.4 (2011): 284–293. PMC. Web. 12 June 2016.
4. Callaway, L.K, Colditz, P.B., Byrne, N.M., Lingwood, B.E., Rowlands, I.J., Foxcroft, K., et al. “Prevention of gestational diabetes: Feasibility issues for an exercise intervention in obese pregnant women.” Diabetes Care, 33(7). 2010: 1457–1459.
5. Harris, G.D., White R.D. “Diabetes management and exercise in pregnant patients with diabetes.” Clinical Diabetes 23(4). 2005: 165–168.
6. Barkat, R., Cordero, Y., Coteron, J., Luaces, M., & Montejo, R. (2012). Exercise during pregnancy improves maternal glucose screen at 24–28 weeks: a randomised controlled trial. British Journal of Sports Medicine, 46(9), 656–661.