July 2019 Issue

Diabetes Management & Nutrition Guide: Exercise and Gestational Diabetes
By Jennifer Van Pelt, MA
Today’s Dietitian
Vol. 21, No. 7, P. 52

Physical activity can help prevent and treat this deleterious pregnancy complication.

Gestational diabetes is the most common medical problem for pregnant women, according to the Centers for Disease Control and Prevention. Annually, gestational diabetes occurs in up to 10% of pregnancies in the United States, and its prevalence is increasing. Typically presenting without symptoms, gestational diabetes develops during pregnancy in women who don’t already have diabetes, causing their blood sugar to rise above normal. Most women are now screened for gestational diabetes because it can increase risk of high blood pressure during pregnancy and the likelihood of a baby weighing 9 lbs or more, which heightens risk of a difficult vaginal birth or requires a cesarean section delivery. Babies born to mothers with untreated gestational diabetes are at increased risk of the following:

• preterm birth, resulting in breathing and other medical issues;
• hypoglycemia (low blood sugar), possibly leading to seizures;
• jaundice;
• hypertrophic cardiomyopathy (enlarged heart); and
• developing type 2 diabetes as a child or adult.

After giving birth, about 50% of women with gestational diabetes eventually develop type 2 diabetes; however, that risk decreases significantly if pregnancy weight is lost and a healthy body weight is achieved.

Professional Guidelines Summary
Research supports the benefits of exercise during pregnancy and for type 2 diabetes management. Therefore, it’s no surprise that exercise is a key intervention for managing gestational diabetes and its associated risks and complications. Dietary modifications coupled with exercise counseling are considered first-line treatments for gestational diabetes. In fact, guidelines endorse regular exercise for the prevention and management of gestational diabetes. In 2015, the American College of Obstetricians and Gynecologists recommended that pregnant women exercise for 20 to 30 minutes at a moderate intensity most or all days of the week and noted that regular exercise during pregnancy can reduce high blood sugar levels caused by gestational diabetes.1 In 2016, the American Diabetes Association (ADA) recommended the same amount and intensity of exercise for pregnant women with gestational diabetes or those at risk of developing gestational diabetes and noted that such exercise decreases the risk of developing the disease. Once gestational diabetes is diagnosed, the ADA recommends either aerobic or resistance training to improve glycemic control, and says that vigorous-intensity exercise decreases the likelihood of excess weight gain caused by gestational diabetes. The ADA also notes that exercise is safe to begin during pregnancy unless there are contraindications, but ideally regular exercise should begin before pregnancy to lower risk of developing gestational diabetes.2 Australian guidelines recommend that women with gestational diabetes do both aerobic and resistance exercise at a moderate intensity, a minimum of three times per week for 30 to 60 minutes per session.3

In late 2018, Canadian medical professionals released the most current and comprehensive guideline on exercise during pregnancy that includes recommendations for gestational diabetes. Their guideline endorses regular exercise during pregnancy to reduce complications, including gestational diabetes, and to optimize the health of the mother and infant. The guideline strongly recommends that pregnant women get at least 150 minutes of moderate-intensity exercise weekly over a minimum of three days per week, but also encourages daily physical activity. Both aerobic and resistance training activities are recommended to achieve maximum benefits; the guideline also notes that adding gentle yoga and/or stretching may be beneficial. Published evidence supports this recommended minimum amount and intensity to achieve clinically meaningful reductions in the risk of developing gestational diabetes. The Canadian researchers also noted that regular prenatal exercise decreased the risk of developing gestational diabetes, and that not exercising during the first trimester increased the risk of developing gestational diabetes, as well as other complications.4

Guidance for Clients
Typically, women who have exercised regularly for most of their lives or are currently athletic will continue their dedication to exercise throughout their pregnancy. Encourage them to learn about their family history of diabetes and get screened for gestational diabetes. A healthy pregnant woman who exercises regularly still may develop gestational diabetes.

For sedentary clients who are planning a pregnancy, encourage them to establish a regular exercise routine that includes at least moderate-intensity aerobic and strength training combined with yoga or stretching on most days of the week. Depending on their baseline fitness level, initial exercise sessions may need to be lower intensity, with gradual increases in intensity. In general, moderate intensity is considered the equivalent of walking briskly for 30 minutes or more daily. Clients can gauge their intensity by assessing their breathing rate—during moderate-intensity exercise, breathing rate should increase such that one can talk somewhat comfortably, but an extended conversation or singing is difficult after a few sentences or verses. Some fitness trackers monitor heart rate and can be used to track exercise intensity.

For pregnant clients, exercise guidance will depend on their prenatal fitness level, any physical limitations, and medical contraindications. To prevent gestational diabetes or minimize its complications, encourage clients to start or maintain exercise in accordance with guidelines. In general, walking and water exercise are appropriate for almost any pregnant woman, regardless of their fitness level, unless they’re confined to bedrest for medical reasons. For those with lower body joint problems and other physical limitations, chair exercise, walking on flat surfaces, and water exercise are good options. Walking is a good aerobic activity, but should be supplemented with resistance training using light weights or resistance bands. Most strength training movements can be adapted to perform seated, if needed. Many yoga studios and fitness facilities offer prenatal yoga classes that can be a beneficial addition to a pregnancy exercise program to prevent and manage gestational diabetes. Prenatal yoga classes also are available in DVD format or online.

In addition, for those clients diagnosed with gestational diabetes, postpartum exercise is important in preventing the development of type 2 diabetes. Incorporating the new baby into daily exercise activities can help with motivation and maintenance of a regular exercise program. For example, once clients are cleared to resume exercise beyond walking, encourage them to participate in “Mommy and Me” exercise classes and brisk walking with a stroller or baby carrier.

With the increasing prevalence of gestational diabetes, raising awareness for screening and communicating the value of regular physical activity in its prevention and management is important for all nutrition professionals who work with prenatal, pregnant, and postpartum clients.

— Jennifer Van Pelt, MA, is a certified group fitness instructor and health care researcher in the Lancaster, Pennsylvania, area.

References
1. ACOG Committee opinion no. 650: physical activity and exercise during pregnancy and the postpartum period. Obstet Gynecol. 2015;126(6):e135-e142.

2. Colberg SR, Sigal RJ, Yardley JE, et al. Physical activity/exercise and diabetes: a position statement of the American Diabetes Association. Diabetes Care. 2016;39(11):2065-2079.

3. Padayachee C, Coombes JS. Exercise guidelines for gestational diabetes mellitus. World J Diabetes. 2015;6(8):1033-1044.

4. Mottola MF, Davenport MH, Ruchat SM, et al. 2019 Canadian guideline for physical activity throughout pregnancy. Br J Sports Med. 2018;52(21):1339-1346.