Exercising throughout pregnancy has numerous benefits, to include: increased prenatal comfort; decreased risk of prenatal complications such as gestational diabetes (GDM) and preeclampsia; decreased risk of cesarean delivery; improved fetal tolerance to labor and stress; and decreased length of labor.
ACOG recommends the minimum of 150 minutes of moderate intensity exercise per week throughout the duration of pregnancy. This recommendation is the same recommendation that the CDC makes for all adults.
Risk Factors with Gestational Diabetes
Risk factors associated with GDM include: high maternal age; family history of type 2 diabetes; over-weight prior to pregnancy; glucose intolerance during pregnancy; and potentially excessive maternal weight gain during early pregnancy. Low muscle strength is associated with a higher incidence of insulin resistance in type 2 diabetes, so may also be a factor for Gestational Diabetes GDM.
So, if someone has these risk factors, or is concerned that they may develop gestational diabetes, is there something we can do to try to reduce the risk? Potentially! In this article we will be discussing how exercise can help reduce the occurrence of GDM! There are other factors that would help such a nutrition and lifestyle, but we will be focusing on exercise.
Exercise to Reduce Your Risk: What Does Research Show?
In one study by Barakat et al, they had 83 pregnant women participate in a fitness program 3 times per week for 35-45 minutes (105-135 minutes per week, so below the ACOG recommendation). The women began the program in their first trimester (weeks 6-9) and completed the program in the end of the third trimester (38-39 weeks). The program was 2 days of resistance training focused workouts and 1 day of water based aerobic activity. The study found that there was a significant difference in the occurrence of GDM when comparing the exercise group (0 had GDM) to the control group (3 had GDM). But this is a small study!
In a systematic review by Davenport et al, they looked at 106 studies that had 273,182 pregnant women studied to review how exercise-only interventions influenced prenatal complications such as Gestational Diabetes GDM, preeclampsia, and hypertension.
The studies they reviewed were considered to be low quality due to the high risk of bias, but found that in 46 random controlled trials (RCTs) with 14,923 pregnant women, that there was a 24% decreased occurrence of Gestational Diabetes GDM in women who exercised. When they analyzed the studies based on studies that had exercise-only interventions, this decreased risk increased to 38%!
Specific Guidance to Reduce Your Risk with Exercise
Now that we understand that exercise can help decrease the risk of GDM, what specific guidance do we have on exercising to prevent it? Is there specific types of exercises that are more beneficial? What about when to exercise; are there certain times during pregnancy when exercise is most beneficial to prevent GDM?
The higher the intensity, the better for prevention of Gestational Diabetes GDM: moderate to vigorous intensity levels of exercise. Exercising at this intensity three days per week for at least 30 minutes seems to be enough to reduce the risk, with a combination of aerobic and resistance training. Although exercising almost everyday would be preferred for at least 20-45 minutes per session.
Since low muscle strength can be associated with insulin resistance, incorporating resistance training could help to decrease the risk of GDM by increasing muscular strength. Strength training could increase signaling proteins that prompt the clearance of glucose. Strength training increases the presence of GLUT 4, protein kinase B, and glycogen synthase that help with insulin sensitivity and glucose transportation.
Exercising regularly before pregnancy had the greatest reduction of risk but exercising the first half of pregnancy also greatly reduces the risk. The combination of both would be optimal.
In our fitness programming, we program resistance training with higher volume to meet both the aerobic and muscular strength demands during a workout. For example, we pair 12x squats with 10x alternating step ups for 3 rounds. This is a continuous effort that develops muscular endurance with resistance training. The heartrate is elevated throughout the entire effort, which would meet the program design to reduce the risk of Gestational Diabetes GDM.
In summary, exercising prior to pregnancy and in the first half at a moderate to vigorous intensity level could reduce your risk of gestational diabetes. Exercise type should be a combination of resistance training and aerobic activity, for at least 150 minutes per week. The decreased occurrence could be as much as 38% throughout pregnancy if you engage in regular exercise, which could be enough motivation to get through your next workout!
prenatal Fitness Programs
REFERENCES:
BARAKAT, 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.
COLBERG, S. R., CASTORINO, K., & JOVANOVIČ, L. (2013). PRESCRIBING PHYSICAL ACTIVITY TO PREVENT AND MANAGE GESTATIONAL DIABETES. WORLD JOURNAL OF DIABETES, 4(6), 256–262. HTTPS://DOI.ORG/10.4239/WJD.V4.I6.256
DAVENPORT, M. H., RUCHAT, S. M., POITRAS, V. J., GARCIA, A. J., GRAY, C. E., BARROWMAN, N., ... & JAMES, M. (2018). PRENATAL EXERCISE FOR THE PREVENTION OF GESTATIONAL DIABETES MELLITUS AND HYPERTENSIVE DISORDERS OF PREGNANCY: A SYSTEMATIC REVIEW AND META-ANALYSIS. BRITISH JOURNAL OF SPORTS MEDICINE, 52(21), 1367-1375.
McKayla J. Niemann, Larry A. Tucker, Bruce W. Bailey, Lance E. Davidson, "Strength Training and Insulin Resistance: The Mediating Role of Body Composition",Journal of Diabetes Research, vol. 2020, Article ID 7694825, 11 pages, 2020.https://doi.org/10.1155/2020/7694825