Effect of Exercise on the Resting Metabolic Rate and Substrate Utilization in Women with Gestational Diabetes Mellitus: Results of a Pilot Study.

Regular physical activity during pregnancy has a positive effect on the mother and fetus. However, there is scarce data regarding the effect of exercise in pregnancies complicated by gestational diabetes mellitus (GDM). The aim of the present parallel, non-randomized, open-label, pilot, clinical study was to examine the effect of two exercise programs on the resting metabolic rate (RMR) and substrate utilization in pregnancies complicated by GDM, compared with usual care (advice for the performance of exercise). Forty-three pregnant women diagnosed with GDM between the 24th and 28th gestational week, volunteered to participate. Three groups were formed: Usual care (n = 17), Walking (n = 14), and Mixed Exercise (n = 12). The Usual care group was given advice on maintaining habitual daily activities without any additional exercise. The Walking group exercised regularly by walking, in addition to the habitual daily activities. Finally, the Mixed Exercise group participated in a program combining aerobics and strength exercises. Training intensity was monitored continuously using lightweight, wearable monitoring devices. The Walking and Mixed Exercise groups participated in the training programs after being diagnosed with GDM and maintained them until the last week of gestation. RMR and substrate utilization were analyzed using indirect calorimetry for all participants twice: between 27th and 28th gestational week and as close as possible before delivery. No differences were observed between groups regarding body composition, age, and medical or obstetrical parameters before or after the exercise programs. RMR was increased after the completion of the exercise interventions in both the Walking (p = 0.001) and the Mixed Exercise arms (p = 0.002). In contrast, substrate utilization remained indifferent. In conclusion, regular exercise of moderate intensity (either walking, or a combination of aerobic and strength training) increases RMR in women with GDM compared to the lack of systematic exercise. However, based on the present, pilot data, these exercise regimes do not appear to alter resting substrate utilization.

TIMER: A Clinical Study of Energy Restriction in Women with Gestational Diabetes Mellitus.

Medical nutrition therapy is an integral part of gestational diabetes mellitus (GDM) management; however, the prescription of optimal energy intake is often a difficult task due to the limited available evidence. The present pilot, feasibility, parallel, open-label and non-randomized study aimed to evaluate the effect of a very low energy diet (VLED, 1600 kcal/day), or a low energy diet (LED, 1800 kcal/day), with or without personalized exercise sessions, among women with GDM in singleton pregnancies. A total of 43 women were allocated to one of four interventions at GDM diagnosis: (1) VLED (n = 15), (2) VLED + exercise (n = 4), (3) LED (n = 16) or (4) LED + exercise (n = 8). Primary outcomes were gestational weight gain (GWG), infant birth weight, complications at delivery and a composite outcomes score. Secondary outcomes included type of delivery, prematurity, small- for-gestational-age (SGA) or large-for-gestational-age (LGA) infants, macrosomia, Apgar score, insulin use, depression, respiratory quotient (RQ), resting metabolic rate (RMR) and middle-upper arm circumference (MUAC). GWG differed between intervention groups (LED median: 12.0 kg; VLED: 5.9 kg). No differences were noted in the type of delivery, infant birth weight, composite score, prevalence of prematurity, depression, RQ, Apgar score, MUAC, or insulin use among the four groups. Regarding components of the composite score, most infants (88.4%) were appropriate-for-gestational age (AGA) and born at a gestational age of 37-42 weeks (95.3%). With respect to the mothers, 9.3% experienced complications at delivery, with the majority being allocated at the VLED + exercise arm (p < 0.03). The composite score was low (range 0-2.5) for all mother-infant pairs, indicating a "risk-free" pregnancy outcome. The results indicate that adherence to a LED or VLED induces similar maternal, infant and obstetrics outcomes.

Guidelines for Medical Nutrition Therapy in Gestational Diabetes Mellitus: Systematic Review and Critical Appraisal.

BACKGROUND: Medical nutrition therapy is the cornerstone of gestational diabetes mellitus treatment. However, guidelines often present contradictory guidance to health care practitioners. OBJECTIVE: To systematically review and critically appraise medical nutrition therapy guidelines for treating patients with gestational diabetes mellitus. DESIGN: We searched Medline, the Cochrane Library, Guidelines International Network, and Google Scholar to retrieve clinical practice guidelines (CPGs) for medical nutrition therapy in gestational diabetes mellitus from professional or governmental organizations, published in English, between January 1, 2007, and November 24, 2018. CPGs were reviewed and appraised using the Appraisal of Guidelines, Research, and Evaluation II instrument. RESULTS: Of 1,286 retrieved articles, 21 CPGs fulfilled the inclusion criteria. CPGs of the Academy of Nutrition and Dietetics, Diabetes Canada, and Malaysia Health Technology Assessment Section received the greatest overall scores and the highest scores concerning rigor of recommendations development. Many CPGs failed to involve multidisciplinary teams in their development, including patients, and often, dietitians. Applicability of the recommendations was low, lacking facilitators and tools to enhance implementation. Many CPGs demonstrated low editorial independence by failing to disclose funding and competing interests. More medical nutrition therapy recommendations were incorporated in the Academy of Nutrition and Dietetics and Malaysia Health Technology Assessment Section CPGs. The Malaysia Health Technology Assessment Section, Diabetes Canada, Academy of Nutrition and Dietetics, and Endocrine Society guidelines were recommended by the review panel herein without modifications. Overall, the CPGs suggested the consumption of adequate protein and the selection of foods with low glycemic index, divided into three main meals and two to four snacks. Weight gain recommendations were mostly based on the Institute of Medicine body mass index thresholds. CONCLUSIONS: With few exceptions, the main developmental limitations of the appraised CPGs involved low rigor of recommendations development, lack of multidisciplinary stakeholder involvement, low applicability, and inadequate editorial independence. This indicates a need for developing more clear, unbiased, practical, and evidence-based CPGs.

Guidelines for exercise during normal pregnancy and gestational diabetes: a review of international recommendations.

OBJECTIVE: Τo summarize and present the main guidelines for exercise during normal pregnancy and pregnancy complicated by gestational diabetes mellitus (GDM). METHODS: Relevant guidelines were retrieved through the electronic databases PubMed (MEDLINE), CENTRAL (Cochrane), and Embase; reference sections of the retrieved publications; proceedings of the main congresses in the field; and websites of relevant organizations published during the years 2000-2018. RESULTS: All guidelines recommend aerobic training from 60 to 150 min/week, with an upper limit of 30 min/day. Exercise is safe, even on a daily basis. Resistance exercise is suggested by five national guidelines (Australia, Canada, Denmark, Norway, and the UK). Discrepancies exist regarding the recommended intensity of exercise. Canada, Japan, Spain, and the UK use both objective (heart rate and maximum oxygen consumption) and subjective criteria (Borg's Scale and talk test) to determine the effectiveness and safety of exercise. Only Canada provides specific recommendations, according to the woman's age and level of physical condition. Women with GDM on no insulin treatment do not need to take extra precautions during exercise. However, due to their condition of hyperglycemia, they must comply with the recommendation issued for type 2 diabetes. The prescription and supervision of exercise should be carried out in a similar way as for uncomplicated pregnancies. Finally, women with GDM on insulin treatment need to follow the same recommendations as for those for pregnant women with type 1 diabetes. CONCLUSION: Health professionals must be informed about the correct planning and execution of physical exercise programs so as to safely achieve the maximum effectiveness of exercise-induced health-related benefits in pregnant women.

Regulation of basal metabolic rate in uncomplicated pregnancy and in gestational diabetes mellitus.

Basal metabolic rate (BMR) is one of the major components of total energy expenditure (TEE). It is affected by various factors, such as body weight, body composition, age, race/ethnicity, gender, biochemical parameters, physical activity, and health status. Gestational diabetes mellitus (GDM) is the most common metabolic disorder during pregnancy and it increases the risk for health complications, such as stillbirth, diabetes mellitus, and cardiovascular disease in later life. Both BMR and GDM have been linked with gestational weight gain (GWG), a fact suggesting a possible association between them. However, assessing BMR is a complex procedure, which becomes more complicated when additional parameters, such as pregnancy and GDM, are taken into consideration. The present review summarizes the current knowledge on factors affecting BMR and its regulation in relation to pregnancy and GDM. Future research addressing these associations should thoroughly consider other factors that affect BMI when designing such studies and/or discussing the BMR outcome results.

Comments on gestational diabetes mellitus: from pathophysiology to clinical practice.

Gestational diabetes mellitus (GDM) is a topic of major interest, as it affects up to 16% of pregnant women and may lead to adverse pregnancy outcomes, which, however, are preventable by appropriate treatment. The aim of the present study was to discuss basic concepts and to critically appraise recent updates on practical issues in the field of GDM. GDM pathophysiology, long-term complications including "fetal programming" and GDM diagnosis are discussed, while clinical practice guidelines on follow-up, medical nutrition therapy, oral hypoglycemic agents and insulin treatment are also reviewed. GDM comprises a serious yet preventable public health problem and prevention by lifestyle changes, early detection and adequate treatment can lead to better health outcomes for both mothers with GDM and their offspring.