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Rethinking Prenatal Exercise Trials: How Can We Improve Translation?

      Regular exercise is important to maintain health and reduce the risk of chronic disease in the general population. The greatest health benefits occur in sedentary individuals who incorporate small amounts of activity into their daily routine. Additional benefits of exercise for pregnant women include reduced rates of maternal and fetal complications, such as pre-eclampsia, gestational hypertension, gestational diabetes, Caesarean section, excessive gestational weight gain, and macrosomia.
      • Mottola M.F.
      • Davenport M.H.
      • Ruchat S.M.
      • et al.
      No. 367-2019 Canadian guideline for physical activity throughout pregnancy.
      The trial of supervised moderate to vigorous prenatal exercise by Mireia Pelaez and colleagues,
      • Pelaez M.
      • CGonzalez-Cerron S.
      • Montejo R.
      • Barakat R.
      Protective effect of exercise on pregnant women including those who exceed weight gain recommendations: randomized controlled trial.
      published in this issue of Mayo Clinic Proceedings, adds to this body of evidence. This single-center, randomized, controlled trial involved more than 300 women in which the control group received usual care while the group randomized to an intervention exercise program exercised three times per week for 24 weeks, in sessions lasting 60 to 65 minutes and of moderate to vigorous intensity. Women who participated in the prenatal exercise intervention were less likely to exceed the Institute of Medicine weight gain recommendations.
      • Pelaez M.
      • CGonzalez-Cerron S.
      • Montejo R.
      • Barakat R.
      Protective effect of exercise on pregnant women including those who exceed weight gain recommendations: randomized controlled trial.
      This was accompanied by a reduced risk of macrosomia and Caesarean section.
      • Pelaez M.
      • CGonzalez-Cerron S.
      • Montejo R.
      • Barakat R.
      Protective effect of exercise on pregnant women including those who exceed weight gain recommendations: randomized controlled trial.
      American
      ACOG Committee Opinion No. 650: Physical activity and exercise during pregnancy and the postpartum period.
      and Canadian
      • Mottola M.F.
      • Davenport M.H.
      • Ruchat S.M.
      • et al.
      No. 367-2019 Canadian guideline for physical activity throughout pregnancy.
      guidelines recommend that pregnant women without contraindications should exercise for at least 150 minutes per week. Unfortunately, many women fall short of these recommendations, and activity levels decrease as pregnancy progresses.
      • Borodulin K.
      • Evenson K.R.
      • Herring A.H.
      Physical activity patterns during pregnancy through postpartum.
      Pregnancy is a unique period, as many women are motivated to make lifestyle changes to benefit their own health and the health of the baby. However, pregnant women also experience barriers to exercise. An interview study of overweight and obese pregnant women revealed that most women believed that their care providers did not provide enough information about exercise during pregnancy.
      • Flannery C.
      • McHugh S.
      • Anaba A.E.
      • et al.
      Enablers and barriers to physical activity in overweight and obese pregnant women: an analysis informed by the theoretical domains framework and COM-B model.
      This concern was amplified among parous women, who expressed concerns that care providers often assumed that they had learned about prenatal exercise in previous pregnancies. A lack of information about how to exercise safely is a common barrier to exercise during pregnancy.
      • Flannery C.
      • McHugh S.
      • Anaba A.E.
      • et al.
      Enablers and barriers to physical activity in overweight and obese pregnant women: an analysis informed by the theoretical domains framework and COM-B model.
      • Krans E.E.
      • Chang J.C.
      A will without a way: barriers and facilitators to exercise during pregnancy of low-income, African American women.
      Women often have questions about which forms of exercise are safe, how many exercise sessions per week are recommended, how long each session should last, and whether intense exercise or exercise in very hot or cold environments is safe for the mom and baby. Safety concerns may be amplified for women with a high-risk pregnancy or a history of miscarriage. This is of particular concern given the increasing prevalence of chronic health problems, such as obesity, hypertension, and diabetes among pregnant women. Concerns about exercise safety may be compounded by traditional beliefs that are not supported by evidence, including the perception that pregnant women should rest.
      • Mottola M.F.
      • Davenport M.H.
      • Ruchat S.M.
      • et al.
      No. 367-2019 Canadian guideline for physical activity throughout pregnancy.
      A focus group study of low-income African American women found that many women had been told that raising their arms above their head could potentially harm the baby by causing the umbilical cord to become wrapped around the baby’s neck.
      • Krans E.E.
      • Chang J.C.
      Low-income African American women's beliefs regarding exercise during pregnancy.
      Care providers should be aware of cultural and societal beliefs about exercise in pregnancy so that they can address these concerns with patients. Finding time to exercise can be especially difficult during pregnancy, as women are adjusting their schedules to accommodate additional medical appointments, plan for maternity leave, and prepare for a new baby. Many women are also balancing these activities with the care of other young children. Common symptoms such as nausea or muscle pain can further limit a woman’s ability to exercise; hence, managing these symptoms is critical to facilitating a healthy lifestyle.
      Unfortunately, clinical obstetrics teams rarely include an exercise physiologist. This may be one factor limiting the translation of clinical trials showing the benefits of prenatal exercise into practice. Successful strategies for integrating lifestyle health professionals into obstetric care already exist, as many obstetrics teams offer patients the opportunity to meet with a dietician. Offering individual or group education sessions with an exercise physiologist who is trained in behavioral interventions may reduce barriers to exercise during pregnancy. These sessions may include information on exercise safety during pregnancy, cultural beliefs about prenatal exercise, and developing strategies to incorporate exercise and physical activity into one’s daily routine. Providers can also offer information on local organizations that offer pregnancy-specific or pregnancy-safe exercise programs. Classes and low-cost neighborhood exercise facilities make it easier for pregnant women to exercise.
      • Krans E.E.
      • Chang J.C.
      A will without a way: barriers and facilitators to exercise during pregnancy of low-income, African American women.
      Group classes also provide an opportunity for expecting mothers to socialize and share experiences and knowledge, which may encourage adherence.
      As with many other trials, a limitation of this trial
      • Pelaez M.
      • CGonzalez-Cerron S.
      • Montejo R.
      • Barakat R.
      Protective effect of exercise on pregnant women including those who exceed weight gain recommendations: randomized controlled trial.
      is that only limited details are provided concerning the exercise intervention. This limits the potential for translation, as prenatal exercise is performed in nonclinical settings and interventions usually include exercises that are unfamiliar to patients. Systematic reviews have examined the quality of reporting among randomized controlled trials using physiotherapy interventions
      • Yamato T.P.
      • Maher C.G.
      • Saragiotto B.T.
      • Hoffmann T.C.
      • Moseley A.M.
      How completely are physiotherapy interventions described in reports of randomised trials?.
      or exercise interventions for patellofemoral pain
      • Holden S.
      • Rathleff M.S.
      • Jensen M.B.
      • Barton C.J.
      How can we implement exercise therapy for patellofemoral pain if we don't know what was prescribed? A systematic review.
      and knee osteoarthritis.
      • Bartholdy C.
      • Nielsen S.M.
      • Warming S.
      • Hunter D.J.
      • Christensen R.
      • Henriksen M.
      Poor replicability of recommended exercise interventions for knee osteoarthritis: a descriptive analysis of evidence informing current guidelines and recommendations.
      No studies completely described all items needed to reproduce the intervention,
      • Holden S.
      • Rathleff M.S.
      • Jensen M.B.
      • Barton C.J.
      How can we implement exercise therapy for patellofemoral pain if we don't know what was prescribed? A systematic review.
      • Bartholdy C.
      • Nielsen S.M.
      • Warming S.
      • Hunter D.J.
      • Christensen R.
      • Henriksen M.
      Poor replicability of recommended exercise interventions for knee osteoarthritis: a descriptive analysis of evidence informing current guidelines and recommendations.
      and 23% of studies did not describe at least half of the items.
      • Yamato T.P.
      • Maher C.G.
      • Saragiotto B.T.
      • Hoffmann T.C.
      • Moseley A.M.
      How completely are physiotherapy interventions described in reports of randomised trials?.
      Some items were more likely to be reported than others. For example, almost all papers include the intervention name and rationale.
      • Yamato T.P.
      • Maher C.G.
      • Saragiotto B.T.
      • Hoffmann T.C.
      • Moseley A.M.
      How completely are physiotherapy interventions described in reports of randomised trials?.
      • Holden S.
      • Rathleff M.S.
      • Jensen M.B.
      • Barton C.J.
      How can we implement exercise therapy for patellofemoral pain if we don't know what was prescribed? A systematic review.
      • Bartholdy C.
      • Nielsen S.M.
      • Warming S.
      • Hunter D.J.
      • Christensen R.
      • Henriksen M.
      Poor replicability of recommended exercise interventions for knee osteoarthritis: a descriptive analysis of evidence informing current guidelines and recommendations.
      Items such as strategies for tailoring the intervention to the needs of individual participants, modifications to the intervention, and adherence were less likely to be reported.
      • Yamato T.P.
      • Maher C.G.
      • Saragiotto B.T.
      • Hoffmann T.C.
      • Moseley A.M.
      How completely are physiotherapy interventions described in reports of randomised trials?.
      • Holden S.
      • Rathleff M.S.
      • Jensen M.B.
      • Barton C.J.
      How can we implement exercise therapy for patellofemoral pain if we don't know what was prescribed? A systematic review.
      • Bartholdy C.
      • Nielsen S.M.
      • Warming S.
      • Hunter D.J.
      • Christensen R.
      • Henriksen M.
      Poor replicability of recommended exercise interventions for knee osteoarthritis: a descriptive analysis of evidence informing current guidelines and recommendations.
      These findings may suggest that researchers focus on the trial results as being the primary product of the research, and overlook the value of the exercise intervention itself.
      The new Consensus on Exercise Reporting Template
      • Slade S.C.
      • Dionne C.E.
      • Underwood M.
      • Buchbinder R.
      Consensus on Exercise Reporting Template (CERT): Explanation and Elaboration Statement.
      encourages scientists to rethink this approach, and to share details of the intervention in a way that is useful to scientists, clinicians, exercise professionals, and patients. The supplemental files provide examples of trials that use different strategies to share details of exercise interventions. These include posting materials on dedicated trial websites, publishing interventions in the Journal of Visualized Experiments, offering a detailed appendix or training manual as a supplement to the paper, and creating online videos or smartphone apps. Investigators should consider several factors when deciding where to share information about interventions. The first is access. Information published behind a scientific journal paywall will be inaccessible to patients, clinicians, and exercise professionals who do not work at an institution with a journal subscription. The second is indexing, as many formats that are accessible to the general public are not indexed by scholarly indexing services such as PubMed. This can make it difficult for other scientists to find the information. One strategy is to post information on a scientific repository (eg, the Open Science Framework) under an open access license that allows others to freely re-use the materials with attribution. Scientists can then share the same information on sites designed for the general public, citing the repository version. The third consideration is long-term preservation of content. Information posted on study websites, for example, will be of little value if there is no plan to preserve the content once trial funding runs out.
      As researchers continue to examine the value of prenatal exercise, scientists and clinicians should focus on promoting translation. This includes developing strategies to encourage more pregnant women to incorporate physical activity and exercise into their daily routines throughout pregnancy and during the postpartum period. Public involvement, community-engaged research, and collaboration with patient groups may be valuable to ensure that pregnant women can benefit from interventions that succeed in clinical trials, such as the important one by Pelaez et al
      • Pelaez M.
      • CGonzalez-Cerron S.
      • Montejo R.
      • Barakat R.
      Protective effect of exercise on pregnant women including those who exceed weight gain recommendations: randomized controlled trial.
      in this issue of Mayo Clinic Proceedings.

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