The potential impact of physical activity during pregnancy on maternal and neonatal outcomes

Physically active pregnancies: Insights from the placenta

Physical activity (PA) positively influences pregnancy, a critical period for health promotion, and affects placental structure and function in ways previously overlooked. Here, we summarize the current body of literature examining the association between PA, placenta biology, and physiology while also highlighting areas where gaps in knowledge exist. PA during pregnancy induces metabolic changes, influencing nutrient availability and transporter expression in the placenta. Hormones and cytokines secreted during PA contribute to health benefits, with intricate interactions in pro- and anti-inflammatory markers. Extracellular vesicles and placental "-omics" data suggest that gestational PA can shape placental biology, affecting gene expression, DNA methylation, metabolite profiles, and protein regulation. However, whether cytokines that respond to PA alter placental proteomic profiles during pregnancy remains to be elucidated. The limited research on placenta mitochondria of physically active gestational parents (gesP), has shown improvements in mitochondrial DNA and antioxidant capacity, but the relationship between PA, placental mitochondrial dynamics, and lipid metabolism remains unexplored. Additionally, PA influences the placenta-immune microenvironment, angiogenesis, and may confer positive effects on neurodevelopment and mental health through placental changes, vascularization, and modulation of brain-derived neurotrophic factor. Ongoing exploration is crucial for unraveling the multifaceted impact of PA on the intricate placental environment.

Pregorexia: a systematic review and meta-analysis on the constructs of body image dissatisfaction and eating disturbances by gestational age in the peripartum

PURPOSE

Pregorexia is a phenomenon posited to occur in the peripartum, characterized by an attempt to counter pregnancy's physiological changes in body shape through reduced calorie intake or increased physical activity.

METHODS

In this pre-registered systematic review and meta-analysis, body image dissatisfaction and eating psychopathology in the peripartum according to gestational age were formally assessed. PubMed was searched up to May 2023. Selection criteria were represented by studies on body image concerns or eating psychopathology in the peripartum (up to 1 year after delivery). The population needed to include women from the general population or among patients with a history of (or current) eating disorder. For the meta-analysis, 17 studies were included: 10 for body image dissatisfaction (2625 individuals overall), 7 for eating behaviors (2551 individuals overall). The interplay between body image and the following themes was examined in depth: the adoption of breastfeeding, peripartum depression, sociocultural influences on body image, sexual disturbances, experiencing or reporting an altered food intake.

RESULTS

Progressive dissatisfaction with body image during pregnancy by gestational age was observed, stably elevated for at least 12 months postpartum. Eating psychopathology was observed as elevated only at 12 months in the postpartum, but not during pregnancy.

DISCUSSION

The current work offers normative values of body image satisfaction and eating psychopathology in the peripartum by gestational age. The relevance of current results was discussed, in order to inform both current clinical practice and future public policies.

LEVEL OF EVIDENCE

Level I-Evidence obtained from: systematic reviews and meta-analyses.

Association of ambient air pollution exposure with low birth weight

Increasing evidence has shown that exposure to air pollution is linked to adverse birth outcomes, but the results are not consistent. This study was performed on a subset of participants from the UK Biobank between 2006 and 2010. The land use regression (LUR) model was constructed to calculate the concentrations of particulate matter (PM2.5, PM2.5-10 and PM10), nitrogen oxides (NOx), and nitrogen dioxide (NO2). Binary logistic/multivariate linear regression models were applied to explore the potential linear relationships between air pollution exposure and newborn low birth weight (LBW) or BW. The Cochran-Armitage trend test was used to explore the possible association between the air pollution level and LBW. A restricted cubic spline (RCS) transformation of exposure variables was applied to visualize the relation of air pollutants to BW. Exposure to air pollutants, especially PM2.5 and PM10, was positively associated with LBW, and the odds ratios (ORs) and 95% confidence intervals (CIs) for each 10-μg/m3 increase in PM2.5 and PM10 were 1.25 ([1.03, 1.51], P = 0.025) and 1.12 ([1.02, 1.24], P = 0.021), respectively. A negative correlation was observed between the BW and PM2.5 (-0.05 [-0.08, -0.02], P = 0.001), PM10 (-0.03 [-0.05, -0.02], P < 0.001), PM2.5-10 (-0.04 [-0.07, -0.01], P < 0.001) and NOx (0.00 [0.00, 0.00], P = 0.021). Additionally, the BW changed dramatically up to a specific point (PM2.5 for 10.74 μg/m3, Pnonlinearity = 0.004; PM10 for 16.06 μg/m3, Pnonlinearity = 0.004; NO2 for 25.58 μg/m3, Pnonlinearity <0.001; and NOx for 39.88 μg/m3, Pnonlinearity <0.001), subsequently becoming relatively stable. PM2.5 and PM10 exposure were positively associated with LBW, and a negative correlation was observed between PM2.5, PM2.5-10, PM10 and NOx and BW.

Effectiveness of interventions to increase device-measured physical activity in pregnant women: systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Interventions that provide pregnant women with opportunities to access and participate in physical activity have been shown to be beneficial to their health. Much of this evidence however has been based on self-reported physical activity data, which may be prone to inflated effects due to recall bias and social desirability bias. No previous synthesis of randomised controlled trials has assessed the effectiveness of these interventions using only device measured data, to assess their health benefits more accurately in pregnant women. This systematic review and meta-analysis aimed to address this evidence gap.

DATA SOURCES

Cochrane Central Register of Controlled Trials, Medline, SportDiscus, APA PsycINFO, Embase and Web of Science databases were queried from inception up to December 2, 2021. An updated search of PubMed was conducted on May 16, 2022.

STUDY ELIGIBILITY CRITERIA

Randomised controlled trials that recruited pregnant women, participating in any physical activity intervention (excluding interventions aimed entirely at body conditioning), compared with standard antenatal care (comparators), using device-measured total physical activity as an outcome were eligible for inclusion.

METHODS

3144 titles and abstracts were screened for eligibility, and 18 met the inclusion criteria. Data were analysed using random effect models, (standardised mean difference and mean difference), using data from baseline to last available follow-up (primary end point), and until between 24 to 30 weeks gestation. Gestational weight gain was also assessed at these timepoints in the included trials.

RESULTS

No significant differences between the groups were found for total physical activity at last available follow-up or 24 to 30 weeks gestation (95% CI 0.03 to 0.27, p = 0.10: 95% CI -0.05 to 0.33, p = 0.15) respectively. On average, pregnant women randomised to a physical activity intervention completed 435 and 449 more steps per day than comparators at last available follow-up and at 24 to 30 weeks gestation (95% CI -0.5-870.6, p = 0.05: 95% CI 5.5-892.7, p = 0.05) respectively. Intervention participants also gained 0.69 kg less (95% CI -1.30 to -0.08, p = 0.03) weight than comparators.

CONCLUSION

Based on device-measured data, interventions to promote physical activity during pregnancy have small but important effects on increasing physical activity and managing excessive gestational weight gain.

Population characteristics associated with adherence to prenatal group-based exercise programs

Community-based supervised group exercise may be an effective option to increase activity levels throughout pregnancy. Previous studies that have explored predictors of low adherence to exercise during pregnancy have not examined group-based settings. We analysed an international cohort of 347 pregnant women who participated in group-based prenatal exercise interventions (from <20 weeks to 34-36 weeks pregnant). Probable adherence predictors informed by previous literature that were assessed included: pre-pregnancy physical activity level and body mass index (BMI) classification, age, number of previous pregnancies, and education level. Adherence was measured by attendance. Adjusted odds ratios (aOR) and 95% confidence intervals (CI) were calculated to explore the relationship between the selected predictors and high adherence (≥70%). Post-secondary education level versus only secondary (aOR 5.28; CI 1.67; 16.72) or primary level (aOR 13.82; CI 4.30; 44.45) presented greater likelihood to have high adherence to the exercise intervention than low adherence. Future research and public health initiatives should consider implementing strategies to overcome education-related barriers to improve accessibility to prenatal exercise.

Physical activity during pregnancy and its effects on neonatal outcomes

INTRODUCTION

Despite the acknowledgement that physical activity is beneficial during pregnancy and may result in positive health outcomes for the newborn child few studies have examined this issue. This research was deemed necessary with the primary objective of identifying possible associations between adherence to American College of Sports Medicine recommendations on neonatal outcome variables at birth.

METHODS

An observational, longitudinal and prospective study focused on a sample of 70 pregnant women (the power score achieved was estimated to be 0.3). Data was collected in three stages (1st and 2nd trimester of pregnancy and 48 h after delivery). The variables analyzed included the physical activity measurement (with accelerometry), neonatal outcomes at birth and the mother's anxiety, dietary intake, anthropometric measures and socio-demographic and lifestyle.

RESULTS

21.4% women were active according to physical activity recommendations. There were no significant differences in neonatal outcomes at birth when comparing adherence to physical activity recommendations and the overall activity levels of the mothers. There were also no statistically significant differences in the birth weights of babies born to active and inactive mothers. Mother's anxiety level, weight gained and dietary intake were not statistically different according to compliance with physical activity behaviour or recommendations.

DISCUSSION

There is no relationship between adherence to physical activity recommendations on neonatal outcome variables at birth. There were also no significant associations with sociodemographic and lifestyle variables. There is a need to identify attitudes associated with negative physical activity behavior to reduce the incidence of comorbidities associated with sedentary lifestyles during pregnancy.

Association of Prepregnancy Nutritional Status and Physical Activity Levels with Birth Size Outcomes among West Sumatran Pregnant Women: Results from the Vitamin D Pregnant Mothers Cohort Study in Indonesia

Background: Maternal and neonatal morbidity is still high in developing countries like in Indonesia. There are several factors may affect maternal health during pregnancy such as physical activity level (PAL) and pre-pregnancy nutritional status. Aim: To analyze the association between maternal physical activity status (PAL) and pre-pregnancy body mass index (PP BMI) with birth size outcomes. Methods: A prospective birth cohort study, Vitamin D Pregnant Mothers (VDPM) Study, to 183 healthy singleton pregnant women. Pre-pregnancy body mass index was classified according to WHO guidelines for Asian Population. Women PAL was measured at the first trimester (T1) and third trimester (T3) during pregnancy using the Global Physical Activity Questionnaire (GPAQ). Birth size outcomes were measured immediately after birth such as birth weight, birth length, and head circumference. Results: Pregnant women at T3 had two times lower physical activity than T1 of pregnancy (OR, 2.18; CI, 1.044-4.57; p = 0.045). Maternal PAL at T1 and T3 were mostly in sedentary level (74.3% and 77.1%, respectively). There was no association between PP BMI, PAL, and birth size outcomes (p > 0.05 for all comparisons). However, the physical activity at T1 had a significant association with birth weight outcomes [MD (95%CI): 155.3 (13.8 – 296.8), p = 0.032]. There was a significant interaction between maternal PAL and PP BMI on birth weight (p interaction = 0.011) and head circumference (p interaction = 0.034). Conclusions: Our study reveals that pre-maternal nutritional status and physical activity behavior during the pregnancy associated with the head circumference and birth weight outcomes. Further large studies are needed to confirm our findings.

Knowledge, Perception and Practice towards the Risks of Excessive Weight Gain during Pregnancy among Pregnant Mothers at Myung Sung Christian Medical General Hospital, Addis Ababa, Ethiopia

Background

Being overweight and obese represents a severe public health deterioration affecting all population in general and vulnerable groups, such as pregnant women in particular. This study aimed to assess the knowledge, perception and practice towards the risks of excessive weight gain during pregnancy among pregnant mothers at Myung Sung Christian Medical General Hospital.

Methods

An institution based cross-sectional study was conducted from July to August, 2019. A systematic random sampling technique was employed to select participants. A total of 176 respondents were included in the study. Data was collected using interviewer administered questionnaire, observation checklist, and measurements of weight and height. Statistical product and service solution version 20.0 was employed for analysis. Descriptive statistics, using tables and charts, was used to present results.

Results

Gestational diabetes mellitus (83.5%) and high blood pressure (80.7%) were the major known risks associated with excessive weight gain during pregnancy. Based on the mean score, 96(54.5%) had poor knowledge while 80(45.5%) had good knowledge about the risks of excessive weight gain. The majority (92.0%) overweight and all obese pregnant mothers did not know their actual weight status. Similarly, 134(76.1%) of the study participants were not engaged in regular physical exercise during the current pregnancy.

Conclusion

This study revealed that pregnant mothers attending in Korean General Hospital were generally poorly knowledgeable on the risks of excessive weight gain during pregnancy, had poor perception on current weight status and poor practices on their weight gain management. Facility based education and community awareness creation should accompany antenatal care services.

Asia-Pacific consensus on physical activity and exercise in pregnancy and the postpartum period

Physical activity and exercise in pregnancy are generally beneficial and enhance the physical and mental health of women. These benefits also prevent excessive weight gain and reduce risks of obesity in pregnancy, such as gestational diabetes, hypertensive disorders, higher rates of caesarean delivery, macrosomia and stillbirth. Thus, there is a need to optimise perinatal exercise and physical activity globally. There is currently no consensus recommendation on the role of physical activity and exercise in pregnancy and the postpartum period in the Asia-Pacific region. In this paper, we present seven key consensus recommendations on physical activity and exercise in pregnancy and the postpartum period by 18 key members representing 10 countries in Asia-Pacific regions during an international workshop of the Asia

Diabetes in Pregnancy Conference in Singapore on 11–12 January 2020. Through these consensus recommendations, we hope to improve the metabolic health of pregnant women living in Asia-Pacific regions by educating the public and guiding healthcare professionals on the safety and importance of physical exercise and activity to benefit pregnant women and after childbirth.

Does exercise during pregnancy impact organs or structures of the maternal-fetal interface?

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 Effect of Maternal Physical Activity and Gestational Weight Gain on Placental Efficiency

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.

Physical activity differentially regulates VEGF, PlGF, and their receptors in the human placenta

Physical activity (PA) has beneficial effects on the function of many organs by modulating their vascular development. Regular PA during pregnancy is associated with favorable short‐ and long‐term outcomes for both mother and fetus. During pregnancy, appropriate vascularization of the placenta is crucial for adequate maternal–fetal nutrient and gas exchange. How PA modulates angiogenic factors, VEGF, and its receptors in the human placenta, is as of yet, unknown. We objectively measured the PA of women at 24–28 and 34–38 weeks of gestation. Participants were considered “active” if they had met or exceeded 150 min of moderate‐intensity PA per week during their 2nd trimester. Term placenta tissues were collected from active (n = 23) or inactive (n = 22) women immediately after delivery. We examined the expression of the angiogenic factors VEGF, PlGF, VEGFR‐1, and VEGFR‐2 in the placenta. Western blot analysis showed VEGF and its receptor, VEGFR‐1 was significantly (p < 0.05) higher both at the protein and mRNA levels in placenta from physically active compared to inactive women. No difference in VEGFR‐2 was observed. Furthermore, immunohistochemistry showed differential staining patterns of VEGF and its receptors in placental endothelial, stromal, and trophoblast cells and in the syncytial brush border. In comparison, PlGF expression did not differ either at the protein or mRNA level in the placenta from physically active or inactive women. The expression and localization pattern of VEGF and its receptors suggest that PA during pregnancy may support a pro‐angiogenic milieu to the placental vascular network.

Adaptation of an exercise intervention for pregnant women to community-based delivery: a study protocol

INTRODUCTION

Despite well-established guidelines and benefits to exercise, the majority of pregnant women in the USA fail to meet recommended activity levels. Studies need to determine feasible ways to translate clinical interventions to community settings by engaging pregnant women in widely accessible locations to ensure benefits to more women. The aim of this study is to adapt and determine feasibility, acceptability and fidelity of the research clinic-based Expecting intervention (NCT02125149) with pregnant women with obesity in community settings.

METHODS AND ANALYSIS

We will use the Replicating Effective Programs (REP) to guide the adaptation and implementation of the research clinic-based intervention into the community. REP provides a four-phase process for implementing evidence-based interventions including collection of feedback from community stakeholders, iterative piloting of the intervention in the community and a process for standardising the intervention across community settings. Following adaptation, the updated intervention will be piloted. The pilot study will include 60 expecting women. We will randomise half to receive the community-adapted Expecting intervention (intervention, N=30) and half to receive standard of care (control, N=30). Feasibility and Acceptability of Intervention Measures are primary outcomes as key indicators of feasibility. Secondary outcomes will include the number of intervention sessions completed, the change in the number of minutes of physical activity as measured by accelerometer, as well as change in health indicators from enrolment to time of delivery and 6 months post-delivery (ie, body mass index, blood pressure and total cholesterol).

ETHICS AND DISSEMINATION

This study has been approved by the Institutional Review Board (#260132). Findings will be shared with study participants and stakeholder advisors through written summaries and in-person presentations; results will also be shared through presentations at scientific conferences and publications in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT04298125; Pre-results.

Maternal prepregnancy body mass index and physical activity during pregnancy assessed by accelerometer

BACKGROUND

Maternal prepregnancy overweight and obesity increase the risk of adverse pregnancy outcomes, whereas physical activity during pregnancy has a beneficial effect on both the mother and the fetus. Limited data are available on how maternal prepregnancy overweight and obesity affect physical activity during pregnancy.

OBJECTIVE

The purpose of this study was to describe the association between prepregnancy body mass index and physical activity during pregnancy.

STUDY DESIGN

An observational prospective cohort study of 400 singleton pregnant women who were attending routine antenatal care at Aarhus University Hospital, Denmark (2010-2015), was conducted. Physical activity was assessed by an accelerometer (SenseWear Armband) for 7 days for each trimester. Participants were stratified in 3 different groups of prepregnancy body mass index: normal weight (body mass index <25 kg/m²), overweight (body mass index 25-29.9 kg/m²), and obese (body mass index ≥30 kg/m²). Physical activity was measured as the number of steps per day, metabolic equivalent of task per day, time in moderate- to vigorous-intensity physical activity (>3 metabolic equivalent of task), and time in vigorous-intensity physical activity (>6 metabolic equivalent of task). Linear regression and multilevel mixed-effects models were used to explore the association between prepregnancy body mass index and physical activity variables during pregnancy.

RESULTS

We found an inverse linear relationship between prepregnancy body mass index and both mean number of steps per day and mean metabolic equivalent of task per day (P<.001). At baseline, women with normal weight walked a median of 1214 steps per day (95% confidence interval, 576-1852) more than women who were obese (P<.05), and women who were overweight walked a median of 948 steps per day (95% confidence interval, 218-1677) more than women who were obese (P<.05). Independent of prepregnancy body mass index, all variables of physical activity decreased over the course of pregnancy (P<.05), with the greatest decrease in the third trimester.

CONCLUSION

Maternal physical activity measured by an accelerometer decreased across pregnancy independent of maternal body mass index status and was inversely associated with prepregnancy body mass index. Thus, being overweight or obese before pregnancy increased the risk of sedentary behavior during pregnancy.

Physical Activity Before and During Pregnancy, Colorado Pregnancy Risk Assessment Monitoring System, 2012-2015

We used 2012-2015 data from the Colorado Pregnancy Risk Assessment Monitoring System to describe changes in self-reported physical activity (PA) before and during pregnancy and used logistic regression to examine factors associated with regular PA. The prevalence of regular PA (ie, 30 or more minutes per day on 5 or more days per week) was 19.1% before pregnancy and decreased to 10.2% during pregnancy. At both times, adjusted odds of regular PA were lower among women who were overweight or had obesity before pregnancy than among those with normal weight. Findings suggest that most women with a recent live birth in Colorado, particularly those who are overweight or have obesity, are not obtaining many health benefits of PA either before or during pregnancy.

Physical Activity During Pregnancy Is Associated with Increased Placental FATP4 Protein Expression

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.

Associations between Prenatal Physical Activity and Neonatal and Obstetric Outcomes-A Secondary Analysis of the Cluster-Randomized GeliS Trial

Prenatal physical activity (PA) was discussed to decrease the incidence of obstetric and neonatal complications. In this secondary cohort analysis of the cluster-randomized GeliS ("healthy living in pregnancy") trial, associations between prenatal PA and such outcomes were investigated. PA behavior was assessed twice, before or during the 12th week (baseline, T0) and after the 29th week of gestation (T1), using the self-reported Pregnancy Physical Activity Questionnaire. Obstetric and neonatal data were collected in the routine care setting. Data were available for 87.2% (n = 1994/2286) of participants. Significant differences between the offspring of women who adhered to PA recommendations at T1 and offspring of inactive women were found in birth weight (p = 0.030) but not in other anthropometric parameters. Sedentary behavior was inversely associated with birth weight at T1 (p = 0.026) and, at both time points, with an increase in the odds of low birth weight (T0: p = 0.004, T1: p = 0.005). Light-intensity PA at T0 marginally increased the odds of caesarean section (p = 0.032), but neither moderate-intensity nor vigorous-intensity activity modified the risk for caesarean delivery at any time point. The present analyses demonstrated associations between prenatal PA and some neonatal and obstetric outcomes.

Greater energy demand of exercise during pregnancy does not impact mechanical efficiency

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.

Examination of the Myokine Response in Pregnant and Non-pregnant Women Following an Acute Bout of Moderate-Intensity Walking

Background

It is recommended that women accumulate 150-min of weekly moderate-intensity physical activity (MPA) when pregnant. Engaging in regular physical activity (PA) confers many health benefits to both the mother and the fetus. However, the molecular mechanisms by which these health benefits are bestowed are not well understood. One potential factor that may be contributing to the observed benefits is myokines, which are small peptides secreted by skeletal muscles. In the non-pregnant population, myokines are believed to be involved in the molecular mechanisms resulting from PA. The objective of this study was to characterize and compare the myokine profile of pregnant and non-pregnant women, after an acute bout of MPA.

Methods

Pregnant (n = 13) and non-pregnant (n = 17) women were recruited from the Ottawa region to undergo a treadmill walking session at moderate-intensity (40–60% heart rate reserve). Pre- and post-exercise serum samples were taken, and a set of 15 myokines were analyzed although only 10 were detected. IL-6 was analyzed using a high-sensitivity assay, while FGF21, EPO, BDNF, Fractalkine, IL-15, SPARC, FABP-3, FSTL-1, and oncostatin were analyzed using various multiplex assays.

Results

The pregnant and non-pregnant groups did not differ in terms of age, height, non/pre-pregnancy weight, BMI, and resting heart rate. Baseline levels of EPO and oncostatin were higher in the pregnant group while FGF21 was higher in the non-pregnant group. Circulating levels of three myokines, FGF21, EPO, and IL-15 significantly increased in response to the acute exercise in the pregnant group. Non-pregnant women exhibited an increase in three myokines, FABP-3, FSTL-1, and oncostatin, while one myokine, EPO, decreased post-exercise. SPARC, fractalkine and BDNF were shown to increase post-exercise regardless of pregnancy status while the response for BDNF was more pronounced in the non-pregnant group.

Conclusion

This is the first study examining myokine response following an acute bout of PA in pregnancy. Moderate intensity PA, which is recommended during pregnancy, elicited an increase in four myokines post-compared to pre-exercise in the pregnant group. Further research is warranted to understand the role of myokines in pregnancy.

The Need to Objectively Measure Physical Activity During Pregnancy: Considerations for Clinical Research and Public Health Impact

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.

The Influence of Objectively Measured Physical Activity During Pregnancy on Maternal and Birth Outcomes in Urban Black South African Women

Objectives Research indicates the beneficial effects of physical activity during pregnancy on maternal health, although controversy still exists regarding its influence on birth outcomes. Little research has been done to objectively measure physical activity during pregnancy in black African women from low-to-middle income countries. The purpose of this study was to examine the association between physical activity and maternal and birth outcomes in this unique population. Methods This observational, longitudinal study assessed total physical activity using a hip-mounted triaxial accelerometer at 14–18 weeks (second trimester, n = 120) and 29–33 weeks (third trimester, n = 90) gestation. Physical activity is expressed as gravity-based acceleration units (mg). Maternal outcomes included both weight and weight gain at 29–33 weeks gestation. Birth outcomes included gestational age, birth weight, ponderal index and Apgar score, measured within 48 h of delivery. Results There was a significant decline in physical activity from the second to the third trimester (12.8 ± 4.1 mg vs. 9.7 ± 3.6 mg, p ≤ 0.01). Physical activity at 29–33 weeks as well as a change in PA was inversely associated with weight change at 29–33 weeks (β = − 0.24; 95% CI − 0.49; − 0.00; p = 0.05 and β = − 0.36; 95% CI − 0.62; − 0.10; p = 0.01, respectively). No significant associations were found between physical activity and birth outcomes. Conclusions for Practice Physical activity during pregnancy may be an effective method to control gestational weight gain, whilst presenting no adverse risk for fetal development, in women from a low-income urban setting.

2019 Canadian guideline for physical activity throughout pregnancy

The objective is to provide guidance for pregnant women and obstetric care and exercise professionals on prenatal physical activity. The outcomes evaluated were maternal, fetal or neonatal morbidity, or fetal mortality during and following pregnancy. 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, Education Resources Information Center, SPORTDiscus, ClinicalTrials.gov and the Trip Database from inception up to 6 January 2017. Primary studies of any design were eligible, except case studies. Results were limited to English-language, Spanish-language 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 methodology. The Guidelines Consensus Panel solicited feedback from end users (obstetric care providers, exercise professionals, researchers, policy organisations, and pregnant and postpartum women). The development of these guidelines followed the Appraisal of Guidelines for Research and Evaluation II instrument. 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.

N° 367-2019 Lignes Directrices Canadiennes Sur L'activité Physique Durant La Grossesse

OBJECTIF

L'objectif est de guider les femmes enceintes et les professionnels de l'obstétrique et de l'exercice en ce qui concerne l'activité physique prénatale. RéSULTATS: Les issues évaluées étaient la morbidité maternelle, fœtale ou néonatale et la mortalité fœtale pendant et après la grossesse. DONNéES: Nous avons interrogé MEDLINE, Embase, PsycINFO, la Cochrane Database of Systematic Reviews, le Cochrane Central Register of Controlled Trials, Scopus et la Web of Science Core Collection, CINAHL Plus with Full Text, Child Development & Adolescent Studies, ERIC, SPORTDiscus, ClinicalTrials.gov de leur création jusqu'au 6 janvier 2017. Les études primaires de tous types étaient admissibles, à l'exception des études de cas. Seules les publications en anglais, en espagnol et en français ont été retenues. Les articles liés à l'activité physique durant la grossesse qui abordaient la morbidité maternelle, fœtale ou néonatale ou la mortalité fœtale étaient admissibles. La qualité des données probantes a été évaluée au moyen de l'approche GRADE (Grading of Recommendations Assessment, Development and Evaluation).

VALEURS

Le groupe d'experts responsable des lignes directrices a recueilli les commentaires d'utilisateurs finaux (fournisseurs de soins obstétricaux, professionnels de l'exercice, chercheurs, organismes responsables de politiques, et femmes enceintes et en période postpartum). La directive clinique a été élaborée au moyen de l'outil Appraisal of Guidelines for Research Evaluation (AGREE) II. AVANTAGES, INCONVéNIENTS, ET COûTS: Les avantages de l'activité physique prénatale sont modérés, et aucun inconvénient n'a été relevé; la différence entre les conséquences désirables et indésirables (avantage net) devrait donc être modérée. La majorité des intervenants et des utilisateurs finaux ont indiqué qu'il serait faisable, acceptable et équitable de suivre ces recommandations, qui nécessitent généralement des ressources minimes de la part des personnes et des systèmes de santé. PRÉAMBULE: Les présentes lignes directrices contiennent des recommandations fondées sur des données probantes au sujet de l'activité physique durant la grossesse visant à favoriser la santé maternelle, fœtale et néonatale. En l'absence de contre-indications (voir la liste détaillée plus loin), le fait de suivre ces lignes directrices est associé à : 1) moins de complications pour le nouveau-né (p. ex., gros par rapport à l'âge gestationnel); et 2) des bienfaits pour la santé maternelle (p. ex., diminution du risque de prééclampsie, d'hypertension gravidique, de diabète gestationnel, de césarienne, d'accouchement opératoire, d'incontinence urinaire, de gain de poids excessif durant la grossesse et de dépression; amélioration de la glycémie; diminution du gain de poids total durant la grossesse; et diminution de la gravité des symptômes dépressifs et de la douleur lombo-pelvienne). L'activité physique n'est pas associée à la fausse couche, à la mortinaissance, au décès néonatal, à l'accouchement prématuré, à la rupture prématurée préterme des membranes, à l'hypoglycémie néonatale, au poids insuffisant à la naissance, aux anomalies congénitales, au déclenchement du travail, ou aux complications à la naissance. En général, une augmentation de l'activité physique (fréquence, durée ou volume) est liée à une augmentation des bienfaits. Cependant, nous n'avons pas trouvé de données probantes concernant l'innocuité ou l'avantage accru de l'exercice à des niveaux considérablement supérieurs aux recommandations. L'activité physique prénatale devrait être vue comme un traitement de première ligne pour réduire le risque de complications de la grossesse et améliorer la santé physique et mentale de la mère. Pour les femmes enceintes qui n'atteignent actuellement pas le niveau recommandé, nous recommandons une augmentation progressive pour l'atteindre. Les femmes déjà actives peuvent continuer de l'être tout au long de la grossesse. Elles pourraient devoir modifier le type d'activité à mesure que leur grossesse avance. Il peut devenir impossible de suivre les lignes directrices pendant certaines périodes en raison de la fatigue ou des inconforts de la grossesse; nous encourageons les femmes à faire ce qu'elles peuvent et à revenir aux recommandations lorsqu'elles en sont capables. Les recommandations qui suivent reposent sur une revue systématique approfondie de la littérature, l'opinion d'experts, la consultation d'utilisateurs finaux et des considérations de faisabilité, d'acceptabilité, de coût et d'équité.

RECOMMANDATIONS

Les recommandations des Lignes directrices canadiennes sur l'activité physique durant la grossesse 2019 sont fournies ci-dessous avec des énoncés indiquant la qualité des données probantes utilisées et la force des recommandations (des explications suivent).

CONTRE-INDICATIONS

Toutes les femmes enceintes peuvent faire de l'activité physique durant la grossesse, sauf celles qui présentent des contre-indications (voir ci-dessous). Celles présentant des contre-indications absolues peuvent poursuivre leurs activités quotidiennes habituelles, mais ne devraient pas faire d'activités plus vigoureuses. Celles présentant des contre-indications relatives devraient discuter des avantages et des inconvénients de l'activité physique d'intensité modérée à vigoureuse avec leur fournisseur de soins obstétricaux avant d'y prendre part.

CONTRE-INDICATIONS ABSOLUES

Contre-indications relatives  FORCE DES RECOMMANDATIONS: Nous avons utilisé le système GRADE pour évaluer la force des recommandations. Les recommandations sont jugées fortes ou faibles en fonction de : 1) l'équilibre entre les avantages et les inconvénients; 2) la qualité globale des données probantes; 3) l'importance des issues (valeurs et préférences des femmes enceintes); 4) l'utilisation de ressources (coût); 5) l'incidence sur l'équité en matière de santé; 6) la faisabilité et 7) l'acceptabilité. Recommandation forte : La majorité ou la totalité des femmes enceintes auraient avantage à suivre la recommandation. Recommandation faible : Les femmes enceintes n'auraient pas toutes avantage à suivre la recommandation; il faut tenir compte d'autres facteurs comme la situation, les préférences, les valeurs, les ressources et le milieu de chaque personne. La consultation d'un fournisseur de soins obstétricaux peut faciliter la prise de décisions. QUALITé DES DONNéES PROBANTES: La qualité des données probantes fait référence au degré de confiance dans les données et va de très faible à élevée. Qualité élevée : Le groupe d'experts responsable des lignes directrices est très convaincu que l'effet estimé de l'activité physique sur l'issue de santé est près de l'effet réel. Qualité moyenne : Le groupe d'experts responsable des lignes directrices a moyennement confiance en l'effet estimé de l'activité physique sur l'issue de santé; l'effet estimé est probablement près de l'effet réel, mais il est possible qu'il soit très différent. Qualité faible : Le groupe d'experts responsable des lignes directrices a peu confiance en l'effet estimé de l'activité physique sur l'issue de santé; l'effet estimé pourrait être très différent de l'effet réel. Qualité très faible : Le groupe d'experts responsable des lignes directrices a très peu confiance en l'effet estimé de l'activité physique sur l'issue de santé; l'effet estimé est probablement très différent de l'effet réel. ^a Il s'agit d'une recommandation faible parce que la qualité des données probantes était faible et que l'avantage net entre les femmes qui étaient physiquement actives et celles qui ne l'étaient pas était petit. ^b Il s'agit d'une recommandation forte parce que, malgré le fait que les données probantes appuyant l'activité physique durant la grossesse pour les femmes en surpoids ou obèses étaient de qualité faible, des données tirées d'essais cliniques randomisés démontraient une diminution du gain de poids durant la grossesse et une amélioration de la glycémie. ^c On parle d'intensité modérée lorsque l'activité est assez intense pour augmenter la fréquence cardiaque de façon perceptible; une personne peut parler, mais pas chanter durant les activités de cette intensité. Pensons par exemple à la marche rapide, à la gymnastique aquatique, au vélo stationnaire (effort modéré), à l'entraînement musculaire, au port de charges modérées et aux travaux ménagers (p. ex., jardinage, lavage de fenêtres). ^d Il s'agit d'une recommandation faible parce que l'incontinence urinaire n'était pas jugée comme étant une issue « critique » et que les données étaient de qualité faible. ^e Il s'agit d'une recommandation faible parce que : 1) la qualité des données probantes était très faible; et 2) bien que nous ayons étudié les inconvénients, il y avait peu de renseignements disponibles sur l'équilibre entre les avantages et les inconvénients. Cette recommandation était principalement fondée sur l'opinion d'experts.

A Dynamical Systems Model of Intrauterine Fetal Growth

The underlying mechanisms for how maternal perinatal obesity and intrauterine environment influence fetal development are not well understood and thus require further understanding. In this paper, energy balance concepts are used to develop a comprehensive dynamical systems model for fetal growth that illustrates how maternal factors (energy intake and physical activity) influence fetal weight and related components (fat mass, fat-free mass, and placental volume) over time. The model is estimated from intensive measurements of fetal weight and placental volume obtained as part of Healthy Mom Zone (HMZ), a novel intervention for managing gestational weight gain in obese/overweight women. The overall result of the modeling procedure is a parsimonious system of equations that reliably predicts fetal weight gain and birth weight based on a sensible number of assessments. This model can inform clinical care recommendations as well as how adaptive interventions, such as HMZ, can influence fetal growth and birth outcomes.

No. 367-2019 Canadian Guideline for Physical Activity throughout Pregnancy

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.

Perceived Barriers to Exercise in the First Trimester of Pregnancy

Regular physical activity has been shown to improve pregnancy outcomes. We sought to identify barriers to exercise during the first trimester of pregnancy. Five hundred forty-nine pregnant women in their first trimester rated barriers to exercise on a scale of 1 (not a barrier) to 5 (a huge barrier) and recorded physical activity (minutes/week). Women were placed into one of three classifications, nonexercisers (zero exercise), infrequent exercisers (<150 minutes/week), or exercisers (≥150 minutes/week). The greatest barriers (mean) were nausea/fatigue (3.0) and lack of time (2.6). Exercisers reported significantly lower barrier levels. Nausea/fatigue was a greater barrier for nonexercisers compared to exercisers (3.6 vs 2.8, p < .001). Focusing education and interventions on these barriers may help pregnant women achieve healthy exercise levels.

Examination of the association of physical activity during pregnancy after cesarean delivery and vaginal birth among Chinese women

Background

The goal was to study whether higher physical activity can increase the success rate of Vaginal Birth after Cesarean Delivery (VBAC).

Methods

We enrolled 823 patients with previous cesarean section delivery history (between January 2015 and December 2017) and measured their physical activity during pregnancy. A final number of 519 patients were included for the trial of labor after cesarean delivery (TOLAC). All patients signed informed consent forms.

Results

We conducted bivariate analyses and identified that several variables were associated with successful VBAC: Prior history of vaginal birth (odds ratio [OR] 2.4, 95% CI 1.8–3.9); previous indication for primary cesarean delivery (OR 2.2, 95% CI 1.5–3.0); age younger than 40 years (OR 2.1, 95% CI 1.3–3.4); Weight gain less than 20 kg (OR 1.5, 95% CI 1.3–2.4); high pelvic/birth weight score (OR 1.4, 95% CI 1.1–2.0); no induction of labor (OR 1.9, 95% CI 1.4–2.8); and estimated prenatal fetal weight (OR 1.4, 95% CI 1.2–1.5). We also found that the bivariate association between physical activity and VBAC was significant (p = 0.002). In addition, there was higher odds of VBAC in women who had active physical activity of more than 150 min/week (adjusted OR 1.86, 95% CI 1.69–2.07). Lower odds of VBAC was associated with older age, weight gain during pregnancy, induction of labor, and having estimated prenatal fetal weight more than 3500 g.

Conclusion

Physical activity during pregnancy may influence the success rate of VBAC in Chinese women. Future studies will be needed to prove the robustness of this association using more detailed exposure and outcome definitions.

Paternal exercise protects mouse offspring from high-fat-diet-induced type 2 diabetes risk by increasing skeletal muscle insulin signaling

Paternal obesity increases, while paternal exercise decreases, offspring obesity and type 2 diabetes (T2D) risk; however, no studies have determined whether a paternal high-fat (HF) diet and exercise interact to alter offspring body weight (BW), adiposity and T2D risk. Three-week-old male C57BL/6 mice were fed a normal-fat (NF) diet (16% fat) or an HF diet (45% fat) and assigned to either voluntary wheel running exercise or cage activity for 3 months prior to mating with NF-diet-fed dams. After weaning, male offspring were fed an NF or HF diet for an additional 3 months. F1 male mice whose fathers ate an HF diet had decreased % body fat accompanied by decreased gene expression of beige adipocyte marker FGF21. However, paternal HF-diet-induced reductions in F1 offspring % body fat normalized but did not reduce T2D risk. Exercise was protective against paternal HF-diet-induced insulin resistance by increasing the expression of insulin signaling (GLUT4, IRS1 and PI3K) markers in skeletal muscle resulting in normal T2D risk. When fathers were fed an HF diet and exercised, a postnatal HF diet increased beiging (PPARγ). Thus, these findings show that increases in T2D risk in male offspring when the father consumes an HF diet can be normalized when the father also exercises preconception and that this protection may occur by increases in insulin signaling potential within offspring skeletal muscle. Future studies should further determine the physiological mechanism(s) underlying the beneficial effects of exercise through the paternal lineage.

Comparing the Effects of Progressive Muscle Relaxation and Physical Activity on Pregnant Women's General Health

Background:

Pregnancy is important because maternal health and well-being directly affects another person's life. This study aimed to compare the effects of progressive muscle relaxation (PMR) and physical activity (PA) on the general health of pregnant women.

Materials and Methods:

This randomized clinical trial was conducted among 96 primiparous women enrolled in a prenatal clinic in Tehran (Iran) between May 3, 2013 and August 7, 2013. The participants were selected through convenience sampling over 3 weeks and randomly assigned to the PMR, PA, and control groups, comprising 32 participants each. Six participants did not complete the follow-up measurement (N = 90). The PMR group underwent three sessions of 1.5–2 h in theoretical and practical training, and in the PMR group, training was given in groups of three to four persons. Both groups performed exercises at home for 8 weeks and recorded them in daily report sheets. The general health of all three groups was assessed before and after intervention by using the General Health Questionnaire-28.

Results:

Differences in the mean (SD) general health scores obtained before and after intervention in the PMR, PA, and control groups were 15.63 (5.73), 19.11 (7.79), and 8.27 (2.14), respectively. One-way analysis of variance test showed a significant difference between the three groups (F = 28.10; p < 0.001).

Conclusions:

As the study results confirm the positive effects of PMR and PA on the subscales of the general health of pregnant women, the two techniques are recommended to promote the general health of pregnant women.

Dose and timing of text messages for increasing physical activity among pregnant women: a randomized controlled trial

Text4baby (T4b), a free nation-wide mobile health information service, delivers health-related text messages (SMS) to pregnant women. The objective of this study was to determine the effectiveness of physical activity (PA) specific SMS to improve PA in pregnant women (vs standard T4b) and the most effective dose/timing of PA-specific SMS to improve PA. Pregnant women (N = 80) were randomized to one of four groups that differed in frequency and time of SMS. The Fitbit™ Flex measured PA. Data were analyzed using mixed model analyses. There were no increases in PA regardless of frequency or time. Those that received six PA SMS/week had greater decreases in activity and greater increases in sedentary time. SMS may not be a "potent" enough strategy to improve PA. Future studies should explore a modified focus on behavior change (e.g., decrease sedentary activity, increase light activity) and incorporate SMS as part of a multi-level approach with other evidence-based strategies.

A role for maternally derived myokines to optimize placental function and fetal growth across gestation

Exercise during pregnancy is associated with improved health outcomes for both mother and baby, including a reduced risk of future obesity and susceptibility to chronic diseases. Overwhelming evidence demonstrates a protective effect of maternal exercise against fetal birth weight extremes, reducing the rates of both large- and small-for-gestational-age infants. It is speculated that this protective effect is mediated in part through exercise-induced regulation of maternal physiology and placental development and function. However, the specific mechanisms through which maternal exercise regulates these changes remain to be discovered. We hypothesize that myokines, a collection of peptides and cytokines secreted from contracting skeletal muscles during exercise, may be an important missing link in the story. Myokines are known to reduce inflammation, improve metabolism and enhance macronutrient transporter expression and activity in various tissues of nonpregnant individuals. Little research to date has focused on the specific roles of the myokine secretome in the context of pregnancy; however, it is likely that myokines secreted from exercising skeletal muscles may modulate the maternal milieu and directly impact the vital organ of pregnancy—the placenta. In the current review, data in strong support of this potential role of myokines will be presented, suggesting myokine secretion as a key mechanism through which maternal exercise optimizes fetal growth trajectories. It is clear that further research is warranted in this area, as knowledge of the biological roles of myokines in the context of pregnancy would better inform clinical recommendations for exercise during pregnancy and contribute to the development of important therapeutic interventions.

Development and Preliminary Validation of a Comprehensive Questionnaire to Assess Women's Knowledge and Perception of the Current Weight Gain Guidelines during Pregnancy

The aim of this study was to develop and validate an electronic questionnaire, the Electronic Maternal Health Survey (EMat Health Survey), related to women's knowledge and perceptions of the current gestational weight gain guidelines (GWG), as well as pregnancy-related health behaviours. Constructs addressed within the questionnaire include self-efficacy, locus of control, perceived barriers, and facilitators of physical activity and diet, outcome expectations, social environment and health practices. Content validity was examined using an expert panel (n = 7) and pilot testing items in a small sample (n = 5) of pregnant women and recent mothers (target population). Test re-test reliability was assessed among a sample (n = 71) of the target population. Reliability scores were calculated for all constructs (r and intra-class correlation coefficients (ICC)), those with a score of >0.5 were considered acceptable. The content validity of the questionnaire reflects the degree to which all relevant components of excessive GWG risk in women are included. Strong test-retest reliability was found in the current study, indicating that responses to the questionnaire were reliable in this population. The EMat Health Survey adds to the growing body of literature on maternal health and gestational weight gain by providing the first comprehensive questionnaire that can be self-administered and remotely accessed. The questionnaire can be completed in 15-25 min and collects useful data on various social determinants of health and GWG as well as associated health behaviours. This online tool may assist researchers by providing them with a platform to collect useful information in developing and tailoring interventions to better support women in achieving recommended weight gain targets in pregnancy.

Prenatal Maternal Physical Activity and Stem Cells in Umbilical Cord Blood

PURPOSE

Early life processes, through influence on fetal stem cells, affect postnatal and adult health outcomes. This study examines the effects of physical activity before and during pregnancy on stem cell counts in umbilical cord blood.

METHODS

We isolated mononuclear cells from umbilical cord blood samples from 373 singleton full-term pregnancies and quantified hematopoietic (CD34(+), CD34(+)CD38(-), and CD34(+) c-kit(+)), endothelial (CD34(+)CD133(+), CD34(+)CD133(+)VEGFR2(+), CD34(+)VEGFR2(+), and CD133(+)VEGFR2(+)), and putative breast (EpCAM(+), EpCAM(+)CD49f(+), EpCAM(+)CD49f(+)CD117(+), CD49f(+)CD24(+), CD24(+)CD29(+), and CD24(+)CD29(+)CD49f(+)) stem/progenitor cell subpopulations by flow cytometry. Information on physical activities before and during pregnancy was obtained from questionnaires. Weekly energy expenditure was estimated based on metabolic equivalent task values.

RESULTS

Prepregnancy vigorous exercise was associated positively with levels of endothelial CD34(+)CD133(+), CD34(+)CD133(+)VEGFR2(+), CD34(+)VEGFR2(+), and CD133(+)VEGFR2(+ )progenitor cell populations (P = 0.02, P = 0.01, P = 0.001, and P = 0.003, respectively); positive associations were observed in samples from the first births and those from the second or later births. Prepregnancy moderate and light exercises and light exercise during the first trimester were not significantly associated with any stem/progenitor cell population. Light exercise during the second trimester was positively associated with CD34(+)VEGFR2(+) endothelial progenitor cells (P = 0.03). In addition, levels of EpCAM(+)CD49f(+) and CD49f(+)CD24(+) breast stem cells were significantly lower among pregnant women who engaged in vigorous/moderate exercise during pregnancy (P = 0.05 and P = 0.02, respectively).

CONCLUSIONS

Vigorous exercise before pregnancy increases the number of endothelial progenitor cells in umbilical cord blood and thus could potentially enhance endothelial function and improve cardiovascular fitness in the offspring. Findings of lower levels of putative breast stem cell subpopulations could have implications on exercise and breast cancer prevention. Prenatal effects of exercise on fetal stem cells warrant further studies.

The Intergenerational Cycle of Obesity and Its Implications for Nursing Care of Childbearing Women

Despite intensive focus and interventions at societal and individual levels, more than a third of people in the United States are overweight or obese, and childhood/adolescent obesity rates have dramatically increased during the past three decades. Biomedical research has shown a clear link between the prenatal environment and lifetime adiposity. Children born to overweight and obese women with impaired glucose metabolism show cardiometabolic consequences throughout their life spans that, in turn, affect their children's adiposity. Awareness of this intergenerational cycle of obesity can prompt nurses to intervene in the preconception, prenatal, and postnatal phases.

Trajectories of objectively-measured physical activity and sedentary time over the course of pregnancy in women self-identified as inactive

There is a need for investigations that document the daily course of pregnancy-related changes in PA and sedentary behavior. The purpose of this study was to describe the trajectory of PA and sedentary behavior and whether they differ among weight status in pregnant women self-identified as inactive. Eighty inactive pregnant women (8-16 weeks) were recruited from a nationwide text-message intervention. PA was measured using a Fitbit. Chi-square analyses and t-tests were used to analyze univariate demographic and PA variables. Mixed model-repeated measures ANOVA was used to analyze trajectory changes in daily PA and sedentary behavior. Light activity (beta [SE] = 2.79 [0.30], p < .001), active time (b [SE] = 1.62 [0.16], p < .001), and steps (b [SE] = 112.21 [10.66], p < .001) increased during the second trimester followed by a precipitous decline during the third trimester. Sedentary behavior followed an opposite pattern (b = - 9.88 [1.07], p < .001). Overweight and obese women took significantly fewer steps/day (b [SE] = - 742.37 [362.57], p < .05 and - 855.94 [381.25], p < .05, respectively) than normal weight women, and obese women had less "active" minutes/day (~> 3.0 metabolic equivalents; b [SE] = - 12.99 [5.89], p < .05) than normal weight women (P's < 0.05). Women who self-identify as inactive, become more sedentary and less physically active as pregnancy progresses. This study was among the first to describe the trajectory of daily PA and sedentary behavior throughout pregnancy. This study may help inform health care provider and patient communication related to PA, sedentary behavior, and the time in which to communicate about these behaviors.

Exercise during pregnancy protects against hypertension and macrosomia: randomized clinical trial

BACKGROUND

The prevalence of all pregnancies with some form of hypertension can be up to 10%, with the rates of diagnosis varying according to the country and population studied and the criteria used to establish the diagnosis. Prepregnancy obesity and excessive gestational weight gain (GWG) of all body mass index (BMI) categories have been associated with maternal hypertensive disorders and linked to macrosomia (>4000 g) and low birthweight (<2500 g). No large randomized controlled trial with high adherence to an exercise program has examined pregnancy-induced hypertension and these associated issues. We investigated whether women adherent (≥80% attendance) to an exercise program initiated early showed a reduction in pregnancy-induced hypertension and excessive GWG in all prepregnancy BMI categories, and determined if maternal exercise protected against macrosomia and low birthweight.

OBJECTIVE

We sought to examine the impact of a program of supervised exercise throughout pregnancy on the incidence of pregnancy-induced hypertension.

STUDY DESIGN

A randomized controlled trial was used. Women were randomized into an exercise group (N = 382) or a control group (N = 383) receiving standard care. The exercise group trained 3 d/wk (50-55 min/session) from gestational weeks 9-11 until weeks 38-39. The 85 training sessions involved aerobic exercise, muscular strength, and flexibility.

RESULTS

High attendance to the exercise program regardless of BMI showed that pregnant women who did not exercise are 3 times more likely to develop hypertension (odds ratio [OR], 2.96; 95% confidence interval [CI], 1.29-6.81, P = .01) and are 1.5 times more likely to gain excessive weight if they do not exercise (OR, 1.47; 95% CI, 1.06-2.03, P = .02). Pregnant women who do not exercise are also 2.5 times more likely to give birth to a macrosomic infant (OR, 2.53; 95% CI, 1.03-6.20, P = .04).

CONCLUSION

Maternal exercise may be a preventative tool for hypertension and excessive GWG, and may control offspring size at birth while reducing comorbidities related to chronic disease risk.

Descriptive Epidemiology of Objectively Measured Walking Among US Pregnant Women: National Health and Nutrition Examination Survey, 2005-2006

The objective of this study was to examine population-based prevalence of walking in the United States among pregnant women. Objectively measured walking data on 197 pregnant women who participated in the National Health and Nutrition Examination Survey 2005-2006 were analyzed. In general, pregnant women showed a level of walking below the recommendation; most walking was at low-intensity levels. These findings suggest that walking, particularly at higher intensity than usual, should be promoted among pregnant women.

Preventing excessive weight gain during pregnancy and promoting postpartum weight loss: a pilot lifestyle intervention for overweight and obese African American women

To test the feasibility and acceptability of a theory-based lifestyle intervention designed to prevent excessive weight gain during pregnancy and promote weight loss in the early postpartum period in overweight and obese African American women. Sixteen pregnant women (≤18 weeks gestation) were recruited from prenatal clinics in Columbia, South Carolina in 2011 and assigned to a lifestyle intervention program. The intervention, guided by formative research, consisted of an individual counseling session followed by eight group sessions alternated with telephone counseling contacts that continued through 36 weeks of gestation. At 6-8 weeks postpartum, participants received a home visit and up to three counseling calls through week 12. Medical charts were reviewed for 38 contemporary controls who met the same inclusion criteria and attended the same prenatal clinics. Compared to controls, study participants gained less total weight, had a smaller weekly rate of weight gain across the 2nd and 3rd trimesters (0.89 vs. 0.96 lbs), and were less likely to exceed weight gain recommendations (56.3 vs. 65.8 %). At 12 weeks postpartum, study participants retained 2.6 lbs from their prepregnancy weight, half of study participants were at their prepregnancy weight or lower, and only 35 % retained ≥5 lbs. The intervention also demonstrated success in promoting physical activity and reducing caloric intake, and was well-received by participants. The initial results were promising. The lessons learned can help inform future studies. The efficacy of our intervention will be tested in a large randomized controlled trial.

An investigation into the exercise behaviours of regionally based Australian pregnant women

OBJECTIVES

Regular exercise during pregnancy is a recommended prenatal care strategy with short and long-term health benefits to mother and child. Unfortunately, most pregnant women are insufficiently active to obtain health benefits and there is evidence that activity levels decrease overall during pregnancy. Physical activity among regionally based women is lower than that of urban-based women within Australia. However, little is currently known about exercise behaviours of regionally based Australian pregnant women. To successfully promote exercise among regionally based pregnant women, a greater understanding of exercise behaviours must first be explored. This study investigated exercise behaviours in a sample of regionally based Australian pregnant women.

DESIGN

Regionally based Australian pregnant women (n=142) completed a modified version of the Godin Leisure-Time Exercise Questionnaire examining exercise behaviours before and during pregnancy.

METHODS

Women self-reported their exercise behaviours, including exercise frequency, intensity, time and type, before and during pregnancy.

RESULTS

Chi-square analysis revealed significantly less (χ(2)=31.66, p<0.05) women participated in exercise during pregnancy (61%) compared to before pregnancy (87%). During pregnancy, respondents exercised at a significantly lower frequency (χ(2)=111.63, p<0.05), intensity (χ(2)=67.41, p<0.05), shorter time/duration (χ(2)=114.33, p<0.05), and significantly less (χ(2)=8.55, p<0.05) women (8%) are meeting 'exercise during pregnancy' guidelines compared to women before pregnancy (49%) meeting physical activity guidelines.

CONCLUSIONS

Exercise during pregnancy decreases to levels significantly lower than what is currently recommended. Public health initiatives that promote exercise among Australian pregnant women should aim to increase frequency, intensity, time and type of exercise to be undertaken during pregnancy.

Self-report Pregnancy Physical Activity Questionnaire overestimates physical activity

OBJECTIVES

Physical activity (PA) research during pregnancy relies heavily on indirect/subjective measures of PA, which may be less accurate than directly measured PA. We tested whether the Pregnancy Physical Activity Questionnaire (PPAQ) could accurately estimate PA by comparing PPAQ results to directly measured PA.

METHODS

In a sample of 29 women who completed the PPAQ, PA was directly measured in the second trimester of pregnancy using Actical® accelerometers (valid day = 10+ hours; 4-7 valid days). Activity variables from the PPAQ were calculated using all questions, and also by only considering the leisure time section. Women were classified as 'active' or 'non-active' using Canadian PA guidelines for adults (150 minutes moderate to vigorous PA (MVPA)/ week, bouts of 10+ minutes). Bonferroni corrections were used to adjust for multiple comparisons. Data presented as mean ± standard deviation or median (interquartile range).

RESULTS

The PPAQ overestimated MVPA by 12.12 (14.34) hours/week in the combined sample, and the difference remained substantial when investigating the non-active [overestimate = 11.54 (10.10) hrs/wk] and the active women [overestimate = 16 ± 11 hrs/wk] separately. PPAQ-measured PA variables did not correlate with any of their respective Actical®-measured variables (p > 0.008). The leisure time PPAQ questions overestimated MVPA by 1 ± 3 hrs/wk, with a positive correlation between PPAQ-leisure time MVPA and Actical®-measured MVPA (r = 0.565, p = 0.001).

CONCLUSION

The PPAQ significantly overestimates MVPA and does not provide an accurate estimate of PA in pregnancy. While PPAQ leisure time questions may help distinguish trends in PA, data from subjective questionnaires may result in misinterpretation of relationships between prenatal PA and health outcomes.

Weight gain in healthy pregnant women in relation to pre-pregnancy BMI, diet and physical activity

OBJECTIVE

to explore gestational weight gain in healthy women in relation to pre-pregnancy Body Mass Index, diet and physical activity.

DESIGN

a cross-sectional survey was conducted among 455 healthy pregnant women of all gestational ages receiving antenatal care from an independent midwife in the Netherlands. Weight gain was assessed using the Institute of Medicine (IOM) guidelines and classified as below, within, or above the guidelines. A multinomial regression analysis was performed with weight gain classifications as the dependent variable (within IOM-guidelines as reference). Independent variables were pre-pregnancy Body Mass Index, diet (broken down into consumption of vegetables, fruit and fish) and physical activity (motivation to engage in physical activity, pre-pregnancy physical activity and decline in physical activity during pregnancy). Covariates were age, gestational age, parity, ethnicity, family income, education, perceived sleep deprivation, satisfaction with pre-pregnancy weight, estimated prepregnancy body mass index, smoking, having a weight gain goal and having received weight gain advice from the midwife.

FINDINGS

forty-two per cent of the women surveyed gained weight within the guidelines. Fourteen per cent of the women gained weight below the guidelines and 44 per cent gained weight above the guidelines. Weight gain within the guidelines, compared to both above and below the guidelines, was not associated with pre-pregnancy Body Mass Index nor with diet. A decline in physical activity was associated with weight gain above the guidelines (OR 0.54, 95 per cent CI 0.33-0.89). Weight gain below the guidelines was seen more often in women who perceived a greater sleep deprivation (OR 1.20, 95 per cent CI 1.02-1.41). Weight gain above the guidelines was seen less often in Caucasian women in comparison to non-Caucasian women (OR 0.22, 95 per cent CI 0.08-0.56) and with women who did not stop smoking during pregnancy (OR 0.49, 95 per cent CI 0.25-0.95).

KEY CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

a decline in physical activity was the only modifiable factor in our population associated with weight gain above the gain recommended by the guidelines. Prevention of reduced physical activity during pregnancy seems a promising approach to promoting healthy weight gain. Interventions to promote healthy weight gain should focus on all women, regardless of pre-pregnancy body mass index.