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The International Olympic Committee expert group on pregnancy has identified a paucity of information regarding training and performance in truly elite athletes. Thus, the purpose of this study was to quantify elite runners' training volume throughout pregnancy and postpartum competition performance outcomes.Forty-two elite (50% competed at the World Championships/Olympic) middle-/long-distance runners' training before, during, and after pregnancy (quality/quantity/type) data (retrospective questionnaire) and competition data (published online) were collected.Running volume decreased significantly ( P0.01) from the first trimester (63 ± 34 km·wk -1 ) to the third trimester (30 ± 30 km·wk -1 ). Participants returned to activity/exercise at ~6 wk postpartum and to 80% of prepregnancy training volumes by 3 months. Participants who intended to return to equivalent performance levels postpregnancy, there was no statistical decrease in performance in the 1 to 3 yr postpregnancy compared with prepregnancy, and ~56% improved performances postpregnancy.This study features the largest cohort of elite runners training and competition outcomes assessed throughout pregnancy, with training volumes being approximately two to four times greater than current guidelines. For the first time, performance was directly assessed (due to the quantifiable nature of elite running), and study participants who intended to return to high-level competition did so at a statistically similar level of performance in the 1- to 3-yr period postpregnancy. Taken together, this article provides much needed insights into current training practices and performance of elite pregnant runners, which should help to inform future training guidelines as well as sport policy and sponsor expectations around return to training timelines and performance.

Evidence-based guidelines represent the highest level of scientific evidence to identify best practices for clinical/public health. However, the availability of guidelines do not guarantee their use, targeted knowledge translation strategies and tools are necessary to help promote uptake. Following publication of the 2019 Canadian Guideline for Physical Activity throughout Pregnancy, the Get Active Questionnaire for Pregnancy, and an associated Health Care Provider Consultation Form for Prenatal Physical Activity were developed to promote guideline adoption and use amongst pregnant individuals and health care providers. This paper describes the process of developing these tools. First, a survey was administered to qualified exercise professionals to identify the barriers and facilitators in using existing prenatal exercise screening tools. A Working Group of researchers and stakeholders then convened to develop an evidence-informed exercise pre-participation screening tool for pregnant individuals, building from previous tool and survey findings. Finally, end-user feedback was solicited through a survey and key informant interviews to ensure tools are feasible and acceptable to use in practice. The uptake and use of these documents by pregnant individuals, exercise, and health care professionals will be assessed in future studies. Novelty: Evidence supports the safety/benefits of exercise for most pregnant individuals; however, exercise is not recommended for a small number of individuals with specific medical conditions. The Get Active Questionnaire for Pregnancy and Health Care Provider Consultation Form for Physical Activity during Pregnancy identify individuals where prenatal exercise may pose a risk, while reducing barriers to physical activity participation for the majority of pregnant individuals.

Background Recent research has shown that pregnant individuals experience weight stigma throughout gestation, including negative comments and judgement associated with gestational weight gain (GWG). Weight bias internalization (WBI) is often a result of exposure to weight stigma and is detrimental to biopsychological health outcomes. The purpose of this study was to explore WBI in pregnancy and compare scores based on maternal weight-related factors including pre-pregnancy body mass index (BMI), obesity diagnosis and excessive GWG. Methods Pregnant individuals in Canada and USA completed a modified version of the Adult Weight Bias Internalization Scale. Self-reported pre-pregnancy height and weight were collected to calculate and classify pre-pregnancy BMI. Current weight was also reported to calculate GWG, which was then classified as excessive or not based on Institute of Medicine (2009) guidelines. Participants indicated if they were diagnosed with obesity by a healthcare provider. Inferential analyses were performed comparing WBI scores according to pre-pregnancy BMI, excessive GWG, and obesity diagnosis. Significance was accepted as p Result 336 pregnant individuals completed the survey, with an average WBI score of 3.9 ± 1.2. WBI was higher among those who had a pre-pregnancy BMI of obese than normal weight (p = 0.04, η2 = 0.03), diagnosed with obesity than not diagnosed (p p Conclusions Pregnant individuals who have a higher BMI, obesity and gain excessively may experience WBI. Given that weight stigma frequently occurs in pregnancy, effective person-oriented strategies are needed to mitigate stigma and prevent and care for WBI.

Background: The authors examined whether or not ≤3 days wearing Actical® accelerometers provided acceptable results in comparison with the recommendation of ≥4 days in women across gestation. Methods: A total of 26, 76, and 57 participants at early, mid, and late pregnancy, respectively, were assessed. Participants were instructed to wear the device for 7 days and women who wore it for ≥4 days were included. For each participant, 3, 2, and 1 day(s) were randomly selected. Paired comparisons, intraclass correlations coefficients, and kappa statistics were performed for ≥4 days (criterion) versus 3, 2, and 1 day(s). Averages (in minutes per day) of sedentary time, light, moderate, vigorous, moderate to vigorous physical activity (PA) and steps per day were examined. Results: When 3 valid days were compared with the criterion, no significant differences were found for any gestational period. The intraclass correlations coefficients were “high” for all PA-related variables. The k values varied from .819 to .838 across pregnancy (“strong”). Two and 1 valid day(s) versus the criterion showed significant differences in some PA intensities, reduced intraclass correlations coefficients, “moderate” k values for 2 valid days (.638–.788) and “minimal-to-moderate” k values for 1 valid day (.367–.755). Conclusion: In pregnant women during early, mid, and late pregnancy, PA data obtained from 3 valid days of wear was equivalent and agreed with ≥4 valid days.

Exercise induces the release of small extracellular vesicles (sEVs) into circulation that are postulated to mediate tissue cross-talk during exercise. We previously reported that pregnant individuals released greater levels of sEVs into circulation after exercise compared to matched non-pregnant controls, but their biological functions remain unknown. In this study, sEVs isolated from the plasma of healthy pregnant and non-pregnant participants after a single bout of moderate-intensity exercise were evaluated for their impact on trophoblasts in vitro. Exercise-associated sEVs were found localized within the cytoplasm of BeWo choriocarcinoma cells, used to model trophoblasts in vitro. Exposure to exercise-associated sEVs did not significantly alter BeWo cell proliferation, gene expression of angiogenic growth factors VEGF and PLGF, or the release of the hormone human chorionic gonadotropin. The results from this pilot study support that exercise-associated sEVs could interact with trophoblasts in vitro, and warrant further investigation to reveal their potential role in communicating the effects of exercise to the maternal–fetal interface.

Pre-pregnancy obesity and excessive gestational weight gain (GWG) are risk factors for future maternal and childhood obesity. Maternal obesity is potentially communicated to the fetus in part by the metabolome, altering the child's metabolic program in early development. Fasting maternal blood samples from 37 singleton pregnancies at 25-28 weeks of gestation were obtained from mothers with pre-pregnancy body mass indexes (BMIs) between 18 and 40 kg/m2. Various health measures including GWG, diet, and physical activity were also assessed. At term (37-42 weeks), a venous umbilical cord sample was obtained. Serum metabolomic profiles were measured using nuclear magnetic resonance spectroscopy as well as a gut and metabolic hormone panel. Maternal and cord serum metabolites were tested for associations with pre-pregnancy BMI, GWG, health outcomes, and gut and metabolic hormones. While cord blood metabolites showed no significant correlation to maternal obesity status or other measured health outcomes, maternal serum metabolites showed distinct profiles for lean, overweight, and obese women. Additionally, four serum metabolites, namely, glutamate, lysine, pyruvate, and valine, allowed prediction of excessive GWG when pre-pregnancy BMI was controlled. Metabolic biomarkers predictive of GWG are reported and, if validated, could aid in the guidance of prenatal weight management plans as the majority of pregnancy weight gain occurs in the third trimester.

Gestational weight gain (GWG) has been shown to impact several maternal-infant outcomes. Since healthcare provider guidance on weight gain and healthy behaviors alone has failed to help women to meet guidelines during pregnancy, a practical adjunctive approach is to deliver evidence-based behavior change programs through mobile interventions. The present study aimed to assess the short-term effect of the SmartMoms Canada app to promote adequate GWG and healthy behaviors. Twenty-nine pregnant women were recruited in this app-based intervention trial to test whether a higher app usage (≥ 3.8 min·weeksup-1/sup) between 12-20 gestational weeks and 24-28 gestational weeks improved GWG, diet, physical activity, and sleep, compared to women with a lower app usage (lt; 3.8 min·weeksup-1/sup). Two-way mixed ANOVA for repeated measures was used to estimate the effect of the app usage and time, as well as their interaction on GWG and healthy behaviors. The likelihood ratio was used to examine the association between app usage categorization and GWG classification. Cramer's V statistic was used to estimate the effect size for interpretation of the association. Pregnant women using the SmartMoms Canada app more frequently had a higher moderate-to-vigorous physical activity (MVPA) daily average when compared with women with a lower usage (mean difference: 17.84 min/day, 95% CI: 2.44; 33.25). A moderate effect size (28.6% vs. 15.4%; Cramer's V = 0.212) was found for the association between app categorization and rate of GWG, representing a greater adherence to the GWG guidelines in women in the higher app usage group vs. the lower app usage group. Considering other physical activity, diet, and sleep variables, no app categorization effect was observed. A short-term higher usage of SmartMoms Canada app has a positive effect on objectively-measured MVPA.

Objective As the prevalence of obesity increases, more women are at risk of potentially experiencing weight stigma in prenatal health care settings. The objective of this scoping review was to summarize the primary literature assessing potential causes of weight stigma in prenatal health care settings and synthesize recommendations for health care providers to improve clinical practice. Methods A search strategy was developed combining the terms pregnancy, weight stigma, obesity, and prenatal care. A systematic search was completed in the following databases: Medline, EMBASE, PsycInfo, CINAHL, Opengrey, and Proquest. Results Eighteen resources were included in this review, of which 17 were qualitative, and one was a mixed-methods study design. Weight stigma occurred in prenatal health care settings when providers: avoided weight-related discussions, assumed lifestyle behaviors, and had poor communication when discussing risks associated with obesity. Recommendations to prevent weight stigma included: offering sensitivity training to discuss obesity during pregnancy, implementing a patient-centred approach, including evaluating individual health behaviors, and providing educational resources to patients explaining potential risks and referrals. Conclusion This review summarizes recommendations to eliminate weight stigma in prenatal health care settings. Practice implications These recommendations can be implemented in clinical practice and can improve the delivery of prenatal care.

INTRODUCTION Adherence to physical activity (PA) and gestational weight gain (GWG) recommendations during pregnancy has been shown to improve maternal and fetal health outcomes, including reducing the risk for chronic diseases. Limited research has evaluated the effect of meeting PA in combination with GWG recommendations on placental efficiency (Pl-E), a surrogate marker of the placenta's ability to exchange nutrients and gas based on surface area. The purpose of this study was to measure and compare Pl-E based on meeting PA and GWG recommendations. METHOD Healthy pregnant women (n = 61) wore accelerometers in their second and third trimesters to objectively measure PA. Women were classified as active or inactive at each time point based on meeting the 2019 Canadian prenatal PA guidelines. Total GWG was calculated as weight measured in the third trimester minus self-reported prepregnancy weight, and were categorized as insufficient (n = 19), adequate (n = 22), and excessive (n = 20) according to the 2009 Institute of Medicine guidelines. Placental weight (PW) and birth weight (BW) were measured within 30 min of delivery and 24-48 h postdelivery, respectively. Pl-E was determined in three ways: BW:PW ratio, residual BW, and measured BW, with a higher value indicating better Pl-E. Pl-E was compared by PA and GWG status using a two-way ANOVA. RESULTS No differences were found in the BW:PW ratio or residual BW corresponding to PA and GWG status. Measured BW was significantly higher in newborns of women who gained weight excessively compared with those who gained insufficient weight (P < 0.05). CONCLUSION These findings suggest that prenatal PA does not compromise Pl-E; however, further research is required to evaluate the potential mechanistic benefits of meeting PA and GWG guidelines on the placenta.

KEY POINTS Obesity is a complex chronic disease in which abnormal or excess body fat (adiposity) impairs health, increases the risk of long-term medical complications and reduces lifespan.[1][1] Epidemiologic studies define obesity using the body mass index (BMI; weight/height2), which can stratify

Placental function is of utmost importance to ensure proper fetal development in utero. Among the placenta's many roles includes the passage of sufficient macronutrients, such as glucose, amino acids, and fatty acids, to the fetus. Macronutrients are carried from maternal circulation to the fetus across transporters within the placenta. The objective of this study was to examine the impact of (i) an acute bout of exercise and (ii) chronic exercise participation on placenta nutrient transporter expression and localization. To investigate the effect of acute exercise, pre- and post-exercise serum was collected from pregnant (n = 5) and non-pregnant (n = 5) women who underwent a moderate-intensity exercise session and used to treat BeWo cells. To assess chronic physical activity, we analyzed term placenta from women categorized as active (n = 10) versus non-active (n = 10). Protein expression and localization for the transporters GLUT1, SNAT1, and FATP4 were examined for both groups. GLUT1 expression in BeWo cells treated with serum from pregnant women was higher compared with that from non-pregnant, independent of exercise. FATP4 protein expression was elevated in the term placenta of active women. Immunohistochemistry analysis of term placenta illustrated increased staining of FATP4 in placental tissue from active women and differential staining pattern of GLUT1 depending on physical activity status. Chronic exercise during pregnancy increases the expression of placental FATP4 in vivo, suggesting greater metabolism and usage of fatty acids. Additionally, serum from pregnant women could contain factors that increase GLUT1 protein expression in vitro. BeWo cells treated with pre- and post-exercise serum from pregnant women resulted in greater GLUT1 expression compared with those treated with pre- and post-exercise serum from non-pregnant women. Physical activity appears to differentially impact key placental transporters involved in the transfer and availability of nutrients from mother to fetus. Future research ought to examine the mechanisms involved in regulating these changes and their impact on fetal growth and health.

Pregnant women are recommended to engage in 150 min of moderate-intensity physical activity per week to reduce pregnancy complications. Many women struggle to remain physically active throughout pregnancy, and there is no consensus about whether women adopt a less efficient movement pattern as they progress through pregnancy and experience gestational weight gain. This study assessed the change in energy expenditure and mechanical efficiency in pregnant women (PREG; n = 10) when performing a walking treadmill task in early, mid, and late pregnancy and also compared with an age- and body mass index-matched, nonpregnant (CON; n = 10) group. On average, the PREG group gained within the Institute of Medicine’s gestational weight gain guidelines (11.6 ± 3.6 kg) and were all inactive (measured using accelerometry), except for 1 participant, by the third trimester, as per the 2019 Canadian physical activity guidelines for pregnant women. Energy expended to complete the walking task increased throughout pregnancy and was higher than the controls (111.5 ± 24.6 kcal) in mid and late pregnancy (139.0 ± 22.2 kcal, p = 0.02, and 147.3 ± 24.6 kcal, p = 0.005, respectively), but not early pregnancy (129.9 ± 18.9 kcal, p = 0.08). Walking mechanical efficiency was similar within pregnant women at each time point and compared to nonpregnant controls. Our findings add to the growing body of evidence demonstrating that pregnant women can safely perform physical activity by showing that walking mechanical efficiency is unchanged at low to moderate intensities. Novelty Energy demand during exercise increases proportionally to weight gain across pregnancy trimesters. However, mechanical efficiency remains unchanged during low- to moderate-intensity walking.

Traditionally, resting heart rate variability (rHRV) is measured for 10 min using the last 5 min for analyses (e.g., criterion period). It is unknown whether the measurement period can be shortened in pregnant women as there are currently no established standards. We aimed to compare shorter time segments (e.g., from the 1st to 10th minutes) of the parasympathetic index natural logarithm transformation of root mean square of successive R–R differences (Ln rMSSD) with the criterion period in pregnant and nonpregnant women. Twelve pregnant (age: 30.8 ± 3.4 years; gestational age: 20.1 ± 5.0 weeks) and 15 nonpregnant women (age: 29.8 ± 4.0 years) were included. rHRV was measured using a portable heart rate monitor for 10 min while sitting. Ln rMSSD difference/agreement between shorter time segments and criterion period was analyzed. The result observed between the 4th–5th minutes was the shortest time segment not different from/highly agreed with the criterion period in pregnant women (difference [95% confidence interval (CI)]: −0.10 [−0.22 to 0.02]/bias ± 1.96 × SD: −0.06 [−0.38 to 0.25]). In nonpregnant women, the 2nd–3rd-minute segment was the shortest with similar results (difference [95% CI]: −0.04 [−0.15 to 0.07]/bias ± 1.96 × SD: −0.03 [−0.39 to 0.32]). The Ln rMSSD was found to be stable from the 5th–10th minutes and the 3rd–10th minutes in pregnant and nonpregnant women, respectively. A shortened rHRV assessment can increase its applicability in clinical/exercise-training settings.Novelty Ln rMSSD can be measured for 5 min in pregnant women, with the last 1-min segment analyzed. The last 1-min segment from 3 min can be used for rHRV measurement in nonpregnant women. The shortened rHRV assessment can facilitate its applicability in clinical/exercise-training settings.

Problem Too much or too little gestational weight gain (GWG) can negatively impact maternal and fetal health, according to Institute of Medicine Guidelines. Background Health care providers are key players in providing reliable evidence-informed prenatal advice related to appropriate GWG. However, there appears to be inconsistent GWG communication among healthcare providers during prenatal care. Aim To determine pregnant women and new mothers’ perceptions of healthcare provider GWG and dietary counselling during the pregnancy period. Methods A reliable and validated cross-sectional electronic survey was administered to currently pregnant women and women who had recently given birth. The web-based questionnaire was self-administered and took 10–25 min. Findings A total of 1507 eligible women participated in the survey. More than half (57%) reported that their healthcare provider talked to them about personal weight gain limits. Of these participants, about a third (34%) of participants were counselled regularly at each or most visits. Among the women that were not counselled on personal GWG limits, over half (56%) reported that healthcare provider guidance would have been helpful to achieve their target weight. Less than half (45%) of participants reported that their healthcare providers discussed dietary requirements or changes in pregnancy. Discussion These findings highlight areas for improvement in prenatal dialogue, which can support better outcomes for both mother and baby. Conclusion A better understanding of pregnant and mothers’ perceptions about weight and diet counselling is needed to understand what may need greater attention and clarification and to improve such dialogue.

Physical activity (PA) during pregnancy provides both maternal and fetal health benefits. It has been theorized that myokines, peptides secreted by contracting skeletal muscle, may play an important mechanistic role in facilitating the health benefits obtained from prenatal exercise. The objective of this review was to synthesize the current literature on the relationship between maternal PA and myokine response. A search strategy was developed using the terms pregnancy, PA, IL-6, IL-10, IL-13, and TNF-α. A systematic search was completed in July 2020, in Medline, SPORTDiscus, EMBASE, CENTRAL, and in November 2020 for unpublished dissertations (grey literature; Proquest). Both human- and animal-based studies of any design were included, while commentaries and editorial articles were excluded. Data were extracted by two independent reviewers and summarized narratively. Data were thematically summarized based on the myokine and whether findings were from human or animal studies. Ten studies were included in this review. Findings from studies that examined IL-6, IL-10, and TNF-α suggest a trimester-specific interaction between PA and myokine levels; no studies evaluated IL-13. Future research should investigate the PA-myokine relationship throughout all stages of gestation.

Metabolomics, the application of analytical chemistry methodologies to survey the chemical composition of a biological system, is used to globally profile and compare metabolites in one or more groups of samples. Given that metabolites are the terminal end-products of cellular metabolic processes, or 'phenotype' of a cell, tissue, or organism, metabolomics is valuable to the study of the maternal-fetal interface as it has the potential to reveal nuanced complexities of a biological system as well as differences over time or between individuals. The placenta acts as the primary site of maternal-fetal exchange, the success of which is paramount to growth and development of offspring during pregnancy and beyond. Although the study of metabolomics has proven moderately useful for the screening, diagnosis, and understanding of the pathophysiology of pregnancy complications, the placental metabolome in the context of a healthy pregnancy remains poorly characterized and understood. Herein, we discuss the technical aspects of metabolomics and review the current literature describing the placental metabolome in human and animal models, in the context of health and disease. Finally, we highlight areas for future opportunities in the emerging field of placental metabolomics.

International guidelines recommend women with an overweight or obese body mass index (BMI) aim to reduce their body weight prior to conception to minimize the risk of adverse perinatal outcomes. Recent systematic reviews have demonstrated that interpregnancy weight gain increases women's risk of developing adverse pregnancy outcomes in their subsequent pregnancy. Interpregnancy weight change studies exclude nulliparous women. This systematic review and meta-analysis was conducted following MOOSE guidelines and summarizes the evidence of the impact of preconception and interpregnancy weight change on perinatal outcomes for women regardless of parity. Sixty one studies met the inclusion criteria for this review and reported 34 different outcomes. We identified a significantly increased risk of gestational diabetes (OR 1.88, 95% CI 1.66, 2.14, I2 = 87.8%), hypertensive disorders (OR 1.46 95% CI 1.12, 1.91, I2 = 94.9%), preeclampsia (OR 1.92 95% CI 1.55, 2.37, I2 = 93.6%), and large-for-gestational-age (OR 1.36, 95% CI 1.25, 1.49, I2 = 92.2%) with preconception and interpregnancy weight gain. Interpregnancy weight loss only was significantly associated with increased risk for small-for-gestational-age (OR 1.29 95% CI 1.11, 1.50, I2 = 89.9%) and preterm birth (OR 1.06 95% CI 1.00, 1.13, I2 = 22.4%). Our findings illustrate the need for effective preconception and interpregnancy weight management support to improve pregnancy outcomes in subsequent pregnancies. ispartof: OBESITY REVIEWS vol:23 issue:1 ispartof: location:England status: published

Misconceptions about pregnant women who have obesity exist in the media and scientific literature. These misconceptions might negatively influence research quality and the delivery of health care. In 2014, Chaput and colleagues[1][1] published a commentary discussing widespread misconceptions about

Aims: An increasingly popular exercise modality for women is high-intensity interval training (HIIT). Limited research has assessed HIIT during pregnancy, and as a result, pregnant women may inquire about HIIT on their own through online searches. The purpose of this study was to systematically search and critically evaluate online resources that women may access when inquiring about performing HIIT during pregnancy. Methods: Following previously published methodology, we systematically examined the online search engine Google with the terms ‘HIIT’ and ‘pregnancy’. Using the 2019 Canadian Guideline for Physical Activity throughout Pregnancy as a reference, we identified evidence-based safety recommendations that apply to all prenatal exercise regimes. All selected links were assessed for whether or not they included evidence-based exercise and pregnancy safety recommendations. Descriptive analyses were performed to report the frequency of each construct. Results: Seventy-six links were retrieved, and 33 relevant links were selected for inclusion. The majority of the retrieved links recommended that women should consult a healthcare provider before beginning any exercise programme (67%), and modify the intensity and types of exercises in the active HIIT bout based on general pregnancy-related changes (73%) and individual comfort level (55%). Just under half of the links recommended modifying intensity based on prepregnancy activity level (46%), offered trimester-specific recommendations (42%), and only 12% mentioned contraindications to exercise. Conclusion: Publicly accessible information online on HIIT during pregnancy does not routinely adhere to evidence-based safety recommendations for prenatal exercise. Further research on HIIT during pregnancy and public dissemination of findings is required.

Exercise during pregnancy has been shown to be associated with improved health outcomes both during and after pregnancy for mother and fetus across the lifespan. Increasing physical activity and reducing sedentary behaviour during pregnancy have been recommended by many researchers and clinicians-alike. It is thought that the placenta plays a central role in mediating any positive or negative pregnancy outcomes. The positive outcomes obtained through prenatal exercise are postulated to result from exercise-induced regulation of maternal physiology and placental development. Considerable research has been performed to understand the placenta's role in pregnancy-related diseases, such as preeclampsia, fetal growth restriction, and gestational diabetes mellitus. However, little research has examined the potential for healthy lifestyle and behavioural changes to improve placental growth, development, and function. While the placenta represents the critical maternal-fetal interface responsible for all gas, nutrient, and waste exchange between the mother and fetus, the impact of exercise during pregnancy on placental biology and function is not well known. This review will focus on prenatal exercise and its promising influence on the structures of the maternal-fetal interface, with particular emphasis on the placenta. Potential molecular mechanistic hypotheses are presented to aid future investigations of prenatal exercise and placental health.

The physiological and molecular mechanisms linking prenatal physical activity and improvements in maternal–fetal health are unknown. It is hypothesized that small extracellular vesicles (EVs, ~ 10–120 nm) are involved in tissue cross-talk during exercise. We aimed to characterize the circulating small EV profile of pregnant versus non-pregnant women after an acute bout of moderate-intensity exercise. Pregnant (N = 10) and non-pregnant control (N = 9) women performed a single session of moderate-intensity treadmill walking for 30 min. Plasma was collected immediately pre- and post-exercise, and small EVs were isolated by differential ultracentrifugation. EV presence was confirmed by western blotting for the small EV proteins TSG-101 and flottilin-1. Small EVs were quantified by size and concentration using nanoparticle tracking analysis and transmission electron microscopy. All EV fractions were positive for TSG-101 and flotillin-1, and negative for calnexin. Mean vesicle size at baseline and percent change in size post-exercise were not different between groups. At baseline, pregnant women had higher levels of small EVs compared to controls (1.83E+10 ± 1.25E+10 particles/mL vs. 8.11E+09 ± 4.04E+09 particles/mL, respectively; p = 0.032). Post-exercise, small EVs increased significantly in the circulation of pregnant compared to non-pregnant women after correcting for baseline values (64.7 ± 24.6% vs. − 23.3 ± 26.1%, respectively; F = 5.305, p = 0.035). Further research is needed to assess the functional roles of exercise-induced small EVs in pregnancy.

The present study analyzed the association between (i) eating habits during pregnancy, (ii) advice from family or friends about gestational weight gain (GWG), and iii) personal effort to stay within weight gain limits, and meeting GWG recommendations. Participants included pregnant and postpartum women who completed the validated electronic maternal health survey (EMat). Sociodemographic, lifestyle variables, and body mass index were covariates used in the analyses. Among all eligible women (1171), and a subset of women receiving a specific GWG target from HCP (365, 31.2%), participants who considered that their eating habits became less healthy, or could not evaluate if habits changed, had a higher likelihood of gaining above (adjusted odds ratio, aOR = 2.62; 95% CI 1.84; 3.73 for the total sample (TS); aOR = 4.79; CI 2.32;9.88 for the subset) GWG guidelines after adjusting for the covariates. Women who received advice from family or friends about how much weight they should gain while pregnant were more likely to experience GWG below (TS: aOR = 1.49; CI 1.02;2.17; subset: aOR = 1.95; CI 1.03;3.68) and above (TS: aOR = 1.42; CI 1.01;1.99; subset: aOR = 1.92; CI 1.06;3.48) guidelines, when compared to women who did not receive family/friends advice. Moreover, lower personal effort to stay within weight gain limits was associated with gaining below (TS: aOR = 1.77; CI 1.07;2.92; subset: aOR = 2.71; CI 1.30; 5.65) GWG guidelines. Women self-reporting less healthy eating habits than before pregnancy, receiving advice from family/friends about GWG, and lower personal effort to stay within guidelines, had an increased odds of weight gain discordant with recommendations.

Background Substance abuse in pregnancy increases the chance of physical and neurobehavioral disabilities as well as many other undesirable fetal outcomes. In nonpregnant populations, physical exercise has shown to be an effective adjunctive therapy option for substance use disorders. Given the known positive maternal and fetal physiological and mental health benefits associated with prenatal exercise, perhaps exercise during pregnancy may also be a viable adjuvant therapy option for women with substance use disorders. The purpose of this scoping review was to summarize the available literature that has assessed the relationship between prenatal exercise and substance use disorders. Methods A search strategy was developed combining the terms pregnancy, exercise/physical activity, and substance use. A systematic search was completed in the following databases: Medline/PubMed, SPORTDiscus, and ProQuest. Substances eligible for inclusion included illicit drugs, alcohol, and cannabis. Retrieved data were categorized as animal or human model studies, and were summarized narratively. Results Eight studies were included in this review (five human studies, three animal model studies). Studies in humans suggest that pregnant women with substance use disorders are interested in engaging in physical activity interventions; however, known acute metabolic and physiological responses to prenatal exercise may be impaired in this population. Rodent models show preliminary evidence for improved mental health outcomes following prenatal exercise for substance use disorders. Conclusion The findings from this review may inform the development of future clinical trials to test the effect of structured exercise programs as an adjunctive treatment option for pregnant women with substance use disorders.

Objective To describe the experiences of weight stigma in prenatal clinical settings among high-risk pregnant women living with obesity and to obtain women's perspectives regarding changes to prenatal health care practices that may reduce weight stigma. Design Qualitative descriptive study. Setting/Local Problem High-risk obstetrics clinic. Weight stigma experienced in prenatal clinical settings can negatively influence maternal health and well-being as well as communication with health care providers. Participants Nine pregnant women with obesity who were receiving specialized prenatal care in their third trimester. Intervention/Measurements Women participated in semistructured telephone interviews. Data were inductively analyzed using a content analysis, whereby coded data were organized to represent experiences of or suggestions provided by pregnant women to reduce weight stigma in prenatal clinical settings. Results Experiences of weight stigma included poor communication, generalizations made about health and lifestyle behaviors, and focusing only on excess body weight during clinical appointments as the cause of negative health outcomes. To reduce weight stigma, women suggested that health care providers practice sensitive communication, offer individualized care for weight management, and reduce the focus on body weight by also independently addressing comorbidities or other health indicators. Conclusion Women interviewed for this study provided suggestions that can be implemented in prenatal clinical settings to reduce weight stigma and improve the delivery of equitable health care.

Poor maternal diet increases the risk of obesity and type 2 diabetes in offspring, adding to the ever-increasing prevalence of these diseases. In contrast, we find that maternal exercise improves the metabolic health of offspring, and here, we demonstrate that this occurs through a vitamin D receptor-mediated increase in placental superoxide dismutase 3 (SOD3) expression and secretion. SOD3 activates an AMPK/TET signaling axis in fetal offspring liver, resulting in DNA demethylation at the promoters of glucose metabolic genes, enhancing liver function, and improving glucose tolerance. In humans, SOD3 is upregulated in serum and placenta from physically active pregnant women. The discovery of maternal exercise-induced cross talk between placenta-derived SOD3 and offspring liver provides a central mechanism for improved offspring metabolic health. These findings may lead to novel therapeutic approaches to limit the transmission of metabolic disease to the next generation.

Taking a patient-oriented approach to developing lifestyle interventions includes incorporating the patient into the program's design, delivery, and evaluation. This commentary assumes that a patient-oriented approach has not yet been implemented and tested in exercise-based interventions designed for pregnant women. We outline and define a patient-oriented approach to conduct exercise-based research and review previous physical activity interventions designed for pregnant women to determine whether a patient-oriented approach was applied. In addition, pregnant women living with obesity may have unique barriers to engaging in prenatal exercise interventions that have not been previously addressed, such as having experienced weight stigma before pregnancy in healthcare and fitness settings. We propose suggestions for future trials to effectively take a patient-oriented approach when designing and implementing prenatal exercise interventions to address patient-informed barriers and incorporate suggested facilitators for physical activity. Given that prenatal activity levels are low and pregnant women may have unique barriers to engaging in exercise interventions, a patient-oriented approach may be an effective strategy to improve inclusivity and equity and, as a result, increase uptake and adherence to the intervention.RéSUMé: L’adoption d’une démarche axée sur le patient ou la patiente, dans l’élaboration d’interventions sur le mode de vie, consiste à intégrer celui-ci ou celle-ci dans la conception, l’exécution et l’évaluation des programmes. Dans notre commentaire, nous présumons qu’une démarche axée sur la patiente n’a pas encore été appliquée et testée dans les interventions fondées sur l’exercice conçues pour les femmes enceintes. Nous décrivons et définissons une démarche axée sur la patiente pour faire de la recherche fondée sur l’exercice, et nous examinons des interventions antérieures d’activité physique conçues pour les femmes enceintes afin de déterminer si une démarche axée sur la patiente a été appliquée. Par ailleurs, les femmes enceintes vivant avec l’obésité peuvent faire face à des obstacles particuliers qui n’ont pas encore été étudiés avant de pouvoir participer à des interventions d’exercice prénatales, comme d’avoir été stigmatisées en raison de leur poids, avant la grossesse, dans des milieux de soins de santé et de conditionnement physique. Nous avançons des suggestions pour que les essais futurs adoptent bien une démarche axée sur la patiente lors de la conception et de la mise en œuvre d’interventions d’exercices prénatals, afin de tenir compte des obstacles mentionnés par les patientes et d’intégrer les moyens qu’elles suggèrent pour favoriser l’activité physique. Comme les niveaux d’activité prénatals sont faibles et que les femmes enceintes peuvent faire face à des obstacles particuliers avant de pouvoir participer à des interventions fondées sur l’exercice, une démarche axée sur la patiente pourrait être un moyen efficace d’améliorer l’inclusivité et l’équité, et par conséquent, d’accroître le recours et l’assiduité à l’intervention.

Maternal lifestyle, in particular physical activity (PA), influences many of the physiological adaptations during pregnancy associated with feto-placental development and growth. There is limited to no information on the link between PA during pregnancy and the molecular mechanisms governing placental function. The aim of this study was to investigate the molecular mechanisms through which maternal PA may influence placental function.The level of PA was measured by accelerometry and gene expression was measured in term placenta with custom polymerase chain reaction (PCR) arrays and microarray analysis followed by a pathway analyses on significantly differentially expressed genes (DEGs).Microarray analysis showed 43 significantly DEGs between active and non-active participants. RT-qPCR validation of a sub-sample of DEGs revealed significant changes in the level of expression between active and non-active moms (student's t-test, p 0.05, n = 11). Genes involved in transport of water (p = 0.00236) and uptake of glycerol (p = 0.00219) were enriched in active moms. PA was also associated with the alteration of alternative splicing patters. The most consistent splicing changes were observed for AQP9 where active moms lacked exon 2.Variations in maternal PA influences placental gene. We show significant expression changes of genes that are involved in transport and localization between active and non-active women. Most notably, the expression of the aquaporin family of genes (e.g. AQP1 and AQP9) were found to be significantly higher in the placentas of active women suggesting an adaptive response for the transport of water and glycerol in this population.

Background: Research on sedentary behavior and effects on maternal and newborn outcomes has been inconclusive. The objective of this report was to correlate sedentary time with maternal and fetal anthropometric measurements and compare the effect on sedentary time based on meeting prenatal activity guidelines. Methods: Healthy pregnant women (N = 61) in their second trimester (24–28 wk gestation) provided 7-day accelerometry data. Outcomes, including neonatal weight, length, and body fat percentage, were collected 24 to 48 hours after delivery. Placenta weight was measured immediately after delivery. Gestational weight gain was calculated by subtracting self-reported prepregnancy weight from measured weight at 38 weeks gestation. Correlations between sedentary time and outcomes were tested with Spearman and Pearson coefficient of correlations in all women separately and in accordance with the 2019 Canadian prenatal exercise guidelines. Results: No significant associations were found between sedentary time and the selected outcomes, even when compared by prenatal exercise level. There was no difference in total time spent sedentary between active (576.7 [52.8] min) and inactive women (599.3 [51.6] min). Conclusions: Meeting exercise recommendations during pregnancy does not significantly decrease total sedentary time. Future studies should aim to evaluate the health effects of both decreasing sedentary time and meeting prenatal exercise guidelines.

Objective To identify sources of weight stigma in physical activity (PA)-related milieus reported by pregnant women living with obesity. We also report person-informed strategies to improve the delivery of PA promotions and prescriptions to prevent weight stigma and improve maternal PA. Design This is a qualitative descriptive study and semi-structured interviews were conducted. Setting and Participants Purposive sampling including pregnant women living with obesity, with a body mass index ≥35.0 kg/m2, ≥18 years of age, and receiving specialized prenatal care were recruited from an obstetrics clinic in Kingston, Canada. Measurement and Findings Data were assessed by a content analysis, whereby coded themes represented sources of weight stigma related to prenatal PA. Demographic characteristics (pre-pregnancy body mass index, age, gestational age) were summarized and presented as means and standard deviations. In-depth interview data were collected from eight women. Average pre-pregnancy BMI, age, and gestational age were 44.6±4.8 kg/m2, 32.0±4.1 years, 31.1±5.8 weeks, respectively. Two sources of weight stigma related to prenatal PA were identified: 1. Lack of visual representation – online images and images found in exercise promotional material do not include women who have obesity; 2. Lack of individualized recommendations – currently available prenatal PA guidelines and/or recommendations from healthcare providers do not always consider individual physical barriers or health goals women may have. Key Conclusion and Implications for Practice By increasing body positive representation of pregnant women exercising and offering person-centered prenatal PA recommendations, maternal PA may improve including women living with obesity. Findings from this work can inform future PA interventions, health promotion programming, and prescriptions from prenatal care providers to implement person-oriented strategies to prevent weight stigma and improve the delivery of care for pregnant women living with obesity.

Objective The objective is to provide guidance for pregnant women, and obstetric care and exercise professionals, on prenatal physical activity. Outcomes The outcomes evaluated were maternal, fetal, or neonatal morbidity or fetal mortality during and following pregnancy. Evidence Literature was retrieved through searches of Medline, EMBASE, PsycINFO, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Scopus and Web of Science Core Collection, CINAHL Plus with Full-text, Child Development & Adolescent Studies, ERIC, Sport Discus, ClinicalTrials.gov, and the Trip Database from database inception up to January 6, 2017. Primary studies of any design were eligible, except case studies. Results were limited to English, Spanish, or French language materials. Articles related to maternal physical activity during pregnancy reporting on maternal, fetal, or neonatal morbidity or fetal mortality were eligible for inclusion. The quality of evidence was rated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology. Values The Guidelines Consensus Panel solicited feedback from end-users (obstetric care providers, exercise professionals, researchers, policy organizations, and pregnant and postpartum women). The development of this guideline followed the Appraisal of Guidelines for Research Evaluation (AGREE) II instrument. Benefits, harms, and costs The benefits of prenatal physical activity are moderate, and no harms were identified; therefore, the difference between desirable and undesirable consequences (net benefit) is expected to be moderate. The majority of stakeholders and end-users indicated that following these recommendations would be feasible, acceptable, and equitable. Following these recommendations is likely to require minimal resources from both individual and health systems perspectives. Preamble This guideline provide evidence-based recommendations regarding physical activity throughout pregnancy in the promotion of maternal, fetal, and neonatal health. In the absence of contraindications (see later for a detailed list), following this guideline is associated with: (1) fewer newborn complications (i.e., large for gestational age); and (2) maternal health benefits (i.e., decreased risk of preeclampsia, gestational hypertension, gestational diabetes, Caesarean section, instrumental delivery, urinary incontinence, excessive gestational weight gain, and depression; improved blood glucose; decreased total gestational weight gain; and decreased severity of depressive symptoms and lumbopelvic pain). Physical activity is not associated with miscarriage, stillbirth, neonatal death, preterm birth, preterm/prelabour rupture of membranes, neonatal hypoglycemia, low birth weight, birth defects, induction of labour, or birth complications. In general, more physical activity (frequency, duration, and/or volume) is associated with greater benefits. However, evidence was not identified regarding the safety or additional benefit of exercising at levels significantly above the recommendations. Prenatal physical activity should be considered a front-line therapy for reducing the risk of pregnancy complications and enhancing maternal physical and mental health. For pregnant women not currently meeting this guideline, a progressive adjustment toward them is recommended. Previously active women may continue physical activity throughout pregnancy. Women may need to modify physical activity as pregnancy progresses. There may be periods when following the guideline is not possible due to fatigue and/or discomforts of pregnancy; women are encouraged to do what they can and to return to following the recommendations when they are able. This guideline were informed by an extensive systematic review of the literature, expert opinion, end-user consultation and considerations of feasibility, acceptability, costs, and equity. Recommendations The specific recommendations in this 2019 Canadian Guideline for Physical Activity Throughout Pregnancy are provided below with corresponding statements indicating the quality of the evidence informing the recommendations and the strength of the recommendations (explanations follow). Contraindications All pregnant women can participate in physical activity throughout pregnancy with the exception of those who have contraindications (listed below). Women with absolute contraindications may continue their usual activities of daily living but should not participate in more strenuous activities. Women with relative contraindications should discuss the advantages and disadvantages of moderate-to-vigorous intensity physical activity with their obstetric care provider prior to participation. Absolute contraindications to exercise are the following: Relative contraindications to exercise are the following: STRENGTH OF THE RECOMMENDATIONS: The GRADE system was utilized to grade the strength of the recommendations. Recommendations are rated as strong or weak based on the: (1) balance between benefits and harms; (2) overall quality of the evidence; (3) importance of outcomes (i.e., values and preferences of pregnant women); (4) use of resources (i.e., cost); (5) impact on health equity; (6) feasibility, and (7) acceptability. Strong recommendation: Most or all pregnant women will be best served by the recommended course of action. Weak recommendation: Not all pregnant women will be best served by the recommended course of action; there is a need to consider other factors such as the individual's circumstances, preferences, values, resources available, or setting. Consultation with an obstetric care provider may assist in decision-making. Quality of the evidence The quality of the evidence refers to the level of confidence in the evidence and ranges from very low to high. High quality: The Guideline Consensus Panel is very confident that the estimated effect of physical activity on the health outcome is close to the true effect. Moderate quality: The Guideline Consensus Panel is moderately confident in the estimated effect of physical activity on the health outcome; the estimate of the effect is likely to be close to the true effect, but there is a possibility that it is substantially different. Low quality: The Guideline Consensus Panel's confidence in the estimated effect of physical activity on the health outcome is limited; the estimate of the effect may be substantially different from the true effect. Very low quality: The Guideline Consensus Panel has very little confidence in the estimated effect of physical activity on the health outcome; the estimate of the effect is likely to be substantially different from the true effect. aThis was a weak recommendation because the quality of evidence was low, and the net benefit between women who were physically active and those who were not was small. bThis was a strong recommendation because, despite low quality evidence supporting physical activity during pregnancy for women categorized as overweight or obese, there was evidence from randomized controlled trials demonstrating an improvement in gestational weight gain and blood glucose. cModerate-intensity physical activity is intense enough to noticeably increase heart rate; a person can talk but not sing during activities of this intensity. Examples of moderate-intensity physical activity include brisk walking, water aerobics, stationary cycling (moderate effort), resistance training, carrying moderate loads, and household chores (e.g., gardening, washing windows). dThis was a weak recommendation because urinary incontinence was was not rated as a "critical" outcome and the evidence was low quality. eThis was a weak recommendation because: (1) the quality of evidence was very low; and (2) although harms were investigated there was limited available information to inform the balance of benefits and harms. This recommendation was primarily based on expert opinion.

In the last decade, an abundance of new research from Canada and internationally has provided substantial evidence for the efficacy of exercise in preventing pregnancy complications and improving long-term maternal and fetal outcomes. Indeed, guidelines for exercise during pregnancy are available from several countries. This includes the expert consensus-based 2003 Joint SOGC and Canadian Society for Exercise Physiology Clinical Practice Guidelines: Exercise in Pregnancy and the Postpartum Period. With the plethora of new scientific evidence, it was vital to re-examine the literature by using the rigorous process followed by previous Canadian health behaviour guidelines.The purpose of this document is to outline the process and outcomes for the re-development of the 2019 Canadian Guideline for Physical Activity Throughout Pregnancy, herein referred to as the Guidelines. The target users for these Guidelines are obstetric care providers, policymakers, and exercise professionals who provide guidance for pregnant women regarding prenatal physical activity.

ObjectiveTo examine the relationships between prenatal physical activity and prenatal and postnatal urinary incontinence (UI).DesignSystematic review with random effects meta-analysis and meta-regression.Data sourcesOnline databases were searched up to 6 January 2017.Study eligibility criteriaStudies of all designs were included (except case studies) if they were published in English, Spanish or French and contained information on the Population (pregnant women without contraindication to exercise), Intervention (subjective or objective measures of frequency, intensity, duration, volume or type of exercise, alone [“exercise-only”] or in combination with other intervention components [e.g., dietary; “exercise + co-intervention”]), Comparator (no exercise or different frequency, intensity, duration, volume and type of exercise) and Outcome (prenatal or postnatal UI).Results24 studies (n=15 982 women) were included. ‘Low’ to ‘moderate’ quality evidence revealed prenatal pelvic floor muscle training (PFMT) with or without aerobic exercise decreased the odds of UI in pregnancy (15 randomised controlled trials (RCTs), n=2764 women; OR 0.50, 95% CI 0.37 to 0.68, I2=60%) and in the postpartum period (10 RCTs, n=1682 women; OR 0.63, 95% CI 0.51, 0.79, I2=0%). When we analysed the data by whether women were continent or incontinent prior to the intervention, exercise was beneficial at preventing the development of UI in women with continence, but not effective in treating UI in women with incontinence. There was ‘low’ quality evidence that prenatal exercise had a moderate effect in the reduction of UI symptom severity during (five RCTs, standard mean difference (SMD) −0.54, 95% CI −0.88 to –0.20, I2=64%) and following pregnancy (three RCTs, ‘moderate’ quality evidence; SMD −0.54, 95% CI −0.87 to –0.22, I2=24%).ConclusionPrenatal exercise including PFMT reduced the odds and symptom severity of prenatal and postnatal UI. This was the case for women who were continent before the intervention. Among women who were incontinent during pregnancy, exercise training was not therapeutic.

ObjectiveThe purpose of this review was to investigate the relationship between prenatal exercise, and low back (LBP), pelvic girdle (PGP) and lumbopelvic (LBPP) pain.DesignSystematic review with random effects meta-analysis and meta-regression.Data sourcesOnline databases were searched up to 6 January 2017.Study eligibility criteriaStudies of all designs were eligible (except case studies and reviews) if they were published in English, Spanish or French, and contained information on the population (pregnant women without contraindication to exercise), intervention (subjective or objective measures of frequency, intensity, duration, volume or type of exercise, alone [“exercise-only”] or in combination with other intervention components [eg, dietary; “exercise + co-intervention”]), comparator (no exercise or different frequency, intensity, duration, volume and type of exercise) and outcome (prevalence and symptom severity of LBP, PGP and LBPP).ResultsThe analyses included data from 32 studies (n=52 297 pregnant women). ‘Very low’ to ‘moderate’ quality evidence from 13 randomised controlled trials (RCTs) showed prenatal exercise did not reduce the odds of suffering from LBP, PGP and LBPP either in pregnancy or the postpartum period. However, ‘very low’ to ‘moderate’ quality evidence from 15 RCTs identified lower pain severity during pregnancy and the early postpartum period in women who exercised during pregnancy (standardised mean difference −1.03, 95% CI −1.58, –0.48) compared with those who did not exercise. These findings were supported by ‘very low’ quality evidence from other study designs.ConclusionCompared with not exercising, prenatal exercise decreased the severity of LBP, PGP or LBPP during and following pregnancy but did not decrease the odds of any of these conditions at any time point.

ObjectiveGestational weight gain (GWG) has been identified as a critical modifier of maternal and fetal health. This systematic review and meta-analysis aimed to examine the relationship between prenatal exercise, GWG and postpartum weight retention (PPWR).DesignSystematic review with random effects meta-analysis and meta-regression. Online databases were searched up to 6 January 2017.Study eligibility criteriaStudies of all designs in English, Spanish or French were eligible (except case studies and reviews) if they contained information on the population (pregnant women without contraindication to exercise), intervention (frequency, intensity, duration, volume or type of exercise, alone [“exercise-only”] or in combination with other intervention components [eg, dietary; “exercise + co-intervention”]), comparator (no exercise or different frequency, intensity, duration, volume or type of exercise) and outcomes (GWG, excessive GWG (EGWG), inadequate GWG (IGWG) or PPWR).ResultsEighty-four unique studies (n=21 530) were included. ‘Low’ to ‘moderate’ quality evidence from randomised controlled trials (RCTs) showed that exercise-only interventions decreased total GWG (n=5819; −0.9 kg, 95% CI −1.23 to –0.57 kg, I2=52%) and PPWR (n=420; −0.92 kg, 95% CI −1.84 to 0.00 kg, I2=0%) and reduced the odds of EGWG (n=3519; OR 0.68, 95% CI 0.57 to 0.80, I2=12%) compared with no exercise. ‘High’ quality evidence indicated higher odds of IGWG with prenatal exercise-only (n=1628; OR 1.32, 95% CI 1.04 to 1.67, I2=0%) compared with no exercise.ConclusionsPrenatal exercise reduced the odds of EGWG and PPWR but increased the risk of IGWG. However, the latter result should be interpreted with caution because it was based on a limited number of studies (five RCTs).

ObjectiveTo investigate the relationships between exercise and incidence of congenital anomalies and hyperthermia.DesignSystematic review with random-effects meta-analysis .Data sourcesOnline databases were searched from inception up to 6 January 2017.Study eligibility criteriaStudies of all designs were eligible (except case studies and reviews) if they were published in English, Spanish or French, and contained information on population (pregnant women without contraindication to exercise), intervention (subjective or objective measures of frequency, intensity, duration, volume or type of exercise, alone [“exercise-only”] or in combination with other intervention components [e.g., dietary; “exercise + co-intervention”]), comparator (no exercise or different frequency, intensity, duration, volume or type of exercise) and outcome (maternal temperature and fetal anomalies).ResultsThis systematic review and meta-analysis included ‘very low’ quality evidence from 14 studies (n=78 735) reporting on prenatal exercise and the odds of congenital anomalies, and ‘very low’ to ‘low’ quality evidence from 15 studies (n=447) reporting on maternal temperature response to prenatal exercise. Prenatal exercise did not increase the odds of congenital anomalies (OR 1.23, 95% CI 0.77 to 1.95, I2=0%). A small but significant increase in maternal temperature was observed from pre-exercise to both during and immediately after exercise (during: 0.26°C, 95% CI 0.12 to 0.40, I2=70%; following: 0.24°C, 95% CI 0.17 to 0.31, I2=47%).Summary/ConclusionsThese data suggest that moderate-to-vigorous prenatal exercise does not induce hyperthermia or increase the odds of congenital anomalies. However, exercise responses were investigated in most studies after 12 weeks’ gestation when the risk of de novo congenital anomalies is negligible.

Background Maternal prenatal smoking is associated with downstream childhood obesity. Although animal research suggests reduced resting energy expenditure (REE), decreased physical activity (PA), and increased energy intake as mechanisms, these relationships are unclear in humans. The objectives were to examine the association of prenatal maternal smoking with non-volitional energy expenditure (REE and the thermic effect of feeding [TEF]), child adiposity, energy intake, free-living PA (daily light PA (LPA), daily moderate-to-vigorous PA (MVPA), daily sedentary behavior (SB)), and screen time (television and computer/video game) in children. Methods As part of a longitudinal study, 46 children (n = 27 controls and n = 19 smoking exposed) with mean age 7.6 ± 2 years were recruited. Body weight and composition (Bioelectrical Impedance), height (Stadiometer), waist circumference (cm; tape), BMI (kg/m2), REE (kcal/day; indirect calorimetry), PA (minutes; Accelerometry), screen time (hours; self-report) and ad libitum energy intake (lunch buffet; 7-day food log) were measured. Effects sizes were evaluated using Cohen's d. Results Relative to controls, after controlling for age and family income, children who were exposed to cigarette smoke in utero exhibited greater waist circumference (p = 0.04, Cohen's d = 1.03), percent body fat (%BF; p = 0.02, Cohen's d = 0.97), and a trend for BMI (p = 0.05, Cohen's d = 0.86). Exposed children did not differ in REE (trend for lower: p = 0.1, Cohen's d = 0.42) or TEF but were shown to have significantly higher ad libitum energy intake (p = 0.02, Cohen's D = 0.70) from the palatable lunch buffet, but not from the out of laboratory 7-day energy intake (p = 0.8). Examining screen time behaviors, exposed children spent more time watching television during the week (p = 0.03, Cohen's D = 0.82), and overall television watching (p = 0.02, Cohen's D = 0.80); there were no group differences in any other screen time behaviors. Conclusions Children exposed to cigarette smoke in utero exhibit greater adiposity, and this exposure may have as contributing factors higher screen time, ad libitum energy intake, and a trend for reduced REE. The data suggest that lifestyle factors such as diet and screen time represent targets for obesity prevention in a high-risk population of young children exposed to prenatal cigarette smoke. Findings also highlight the need for smoking cessation programs to reduce downstream obesity in offspring.

Objective Fetal exposure to an intrauterine environment affected by maternal obesity and excessive gestational weight gain increases the likelihood of infants born large for gestational age and childhood obesity. This study examined behavioural factors and lifestyle practices associated with women's perceived attainability of meeting the 2009 Institute of Medicine (IOM) weight gain guidelines. Methods Cross-sectional data were collected from pregnant (n = 320) and postpartum (n = 1179) women who responded to the validated Canadian Electronic Maternal (EMat) health survey. Consenting women completed the survey through REDCap™ a secure, web-based data capture platform. Multiple logistic regression analyses were used to evaluate correlates associated with meeting or not meeting IOM recommendations. Odds ratios (ORs) were adjusted for relevant behavioural and sociodemographic covariates. Results There were no significant differences between adjusted and unadjusted ORs for self-efficacy, barriers, and facilitators to weight gain during pregnancy. Women who reported worry regarding weight gain were significantly less likely to meet IOM guidelines (OR = 0.48, 95% CI = 0.33-0.69). Perceived controllability of behaviour was significantly associated with meeting IOM guidelines. An internal locus of control for weight gain was associated with an increased odds of meeting guidelines when women perceived to be in control of their weight gain (OR = 1.75, 95% CI = 1.29-2.37), healthy and exercised (OR = 1.91, 95% CI = 1.34-2.71), and when no barriers to healthy weight gain were perceived (OR = 1.43, 95% CI = 1.04-1.95); whereas, an external locus of control in which women viewed weight gain as beyond their control, was associated with a significantly reduced odds of achieving guidelines (OR = 0.58, 95% CI = 0.39-0.88). Conclusions Self-efficacy and perceived controllability of behaviour are key factors to consider when developing pregnancy-specific interventions to help women achieve guideline-concordant weight gain and ensure the downstream health of both mother and infant.

Importance Gestational weight gain (GWG) is an independent and modifiable factor for a healthy pregnancy. Gestational weight gain above or below the Institute of Medicine Guidelines has been shown to impact both maternal and fetal health (eg, gestational diabetes, hypertension, downstream obesity). Healthcare providers (HCPs) have the potential to be reliable sources of evidence-based weight information and advice during pregnancy. Objective The aim of this study was to summarize the literature assessing GWG discussions between patients and their HCPs in a clinical setting to better understand the knowledge that is currently being exchanged. Evidence Acquisition A literature review was conducted by searching Ovid Medline, CINAHL, and Embase databases. All relevant primary research articles in English that assessed GWG discussions were included, whereas intervention studies were excluded. Results A total of 54 articles were included in this review. Although the overall prevalence and content of GWG counseling varied between studies, counseling was often infrequent and inaccurate. Healthcare providers tended to focus more on women experiencing obesity and excessive GWG, as opposed to the other body mass index categories or inadequate GWG. Women of higher socioeconomic status, older age, nulliparous, history of dieting, low physical activity, and those categorized as overweight/obese were more likely to receive GWG advice. Patients also reported receiving conflicting facts between different HCP disciplines. Conclusions The evidence regarding GWG counseling in prenatal care remains variable, with discrepancies between geographic regions, patient populations, and HCP disciplines. Relevance Healthcare providers should counsel their pregnant patients on GWG with advice that is concordant with the Institute of Medicine Guidelines.

Engaging in recommended levels of physical activity during pregnancy can provide a host of physical and mental health benefits for the expecting mother and her child. However, methodological issues related to physical activity measurement have plagued many studies examining the effects of physical activity during this important life stage. Burgeoning support exists for the more widespread use of objective methods, and accelerometers specifically, for an accurate appraisal of maternal physical activity. In this commentary, we highlight discrepancies between activity estimates obtained via self-report and objective measures and describe the implications of erroneous measurement when making clinical recommendations and in conducting future physical activity and pregnancy research. Most importantly, we aim to foster academic discussion and propose a call to action requiring a paradigm shift where we acknowledge the shortcomings of self-report and move toward an empirically driven approach for physical activity measurement. Results from more high-quality research studies will help support public health messaging and facilitate trust among health care providers, clinical researchers, and expecting mothers regarding the health benefits of physical activity recommendations.

Background The teratogenic risk associated with maternal hyperthermia (i.e., core temperature ≥39.0 °C) has been a crucial motive in understanding thermoregulatory responses in pregnancy. To date, a substantial number of studies have focused on core temperature responses in a wide range of exercise intensities, duration, and ambient temperatures. Fortunately, none have reported core temperatures exceeding 39.0 °C. Nonetheless, there are limited studies that have provided substantial insight into both dry and evaporative heat loss mechanisms involved in facilitating the maintenance of core temperature (≥39.0 °C) during heat stress in pregnant women. The purpose of this scoping review was to summarize the available literature that has assessed heat loss responses in studies of human pregnancy. Methods A search strategy was developed combining the terms pregnancy, thermoregulation, and adaptation. A systematic search was performed in the following databases: PubMed, Embase, Scopus, and ProQuest. Studies eligible for inclusion included pregnant women between the ages of 18–40 years old, and at least one measurement of the following: sweating, blood flow, skin temperature, and behavioural responses. Retrieved data were categorized as evaporative (sweating), dry or behavioural heat loss responses and summarized narratively. Results Thirty-three studies were included in this review (twenty-nine measured physiological responses and four measured behavioural responses). Studies suggest that during exercise, evaporative (sweating) and dry (skin blood flow and temperature) heat loss responses increase from early to late pregnancy in addition to greater cardiac output, blood volume and reduced vascular resistance. Behavioural practices related to heat loss responses are also influenced by cultural/religious expectations, personal preferences and sociodemographics. Conclusion The findings from this review suggest that pregnancy modifies evaporative (sweating), dry and behavioural heat loss. However, future studies have an opportunity to compare heat loss measurements accounting for gestational weight gain and thermal sensation/comfort scale to associate physiological responses with perceptual responses across pregnancy.

Introduction Gestational weight gain (GWG) outside of the 2009 Institute of Medicine guidelines may be harmful to women and their fetuses. Prenatal health care providers (HCPs) are important sources of health information, but not all discuss GWG with their patients. The Canadian Obesity Network's 5As (ask, assess, advise, agree, and assist) of Healthy Pregnancy Weight Gain (5As) is a tool developed to help HCPs counsel their patients on GWG. The main objective of this study was to evaluate the impact of the 5As tool on patient perceptions of GWG discussions with their HCP and to identify suggestions to improve the tool. Methods A quasiexperimental study design was conducted whereby HCPs were trained in using the 5As tool (intervention). Patients were then queried at baseline and postintervention using an electronic questionnaire measuring patient-perceived 5As counseling. Inclusion criteria for pregnant women were (1) currently attending their first appointment with participating HCPs, (2) English-speaking, and (3) over 18 years of age. Results One hundred pregnant women (50 baseline, 50 postintervention) and 15 HCPs (11 midwives, 4 obstetricians) participated. Participants receiving care from 5As-trained HCPs reported scores twice as high (P = .047) in being asked about and were approximately 3 times more likely to be advised an exact amount of target weight gain (P = .03). HCPs suggested improving patient handouts and HCP education on GWG guidelines as well as reducing the content presented in the 5As tool. Discussion The 5As Tool is effective at initiating HCP-mediated GWG counseling; further research is needed to examine the usefulness of the 5As in clinical practice throughout the length of a full pregnancy. Whether the uptake of the 5As tool contributes to prenatal behavior change remains to be established. Future steps include modifying the tool based on HCP feedback, the development of novel knowledge translation tools, and improved HCP and patient education.