Walking Program of Low or Vigorous Intensity During Pregnancy Confers an Aerobic Benefit

Effects of a 12-week walking intervention on circulating lipid profiles and adipokines in normal weight and abdominal obese female college students

Background/objectives

Regular exercise such as aerobic exercise has been shown to reduce the risk of some diseases such as cardiovascular disease (CVD). However, only few studies have investigated the impact of regular aerobic exercise on non-obese and overweight/obese persons. Therefore, this study was designed to compare the effect of a 12-week 10,000 steps a day walking intervention on the body composition, serum lipids, adipose tissue function, and obesity-associated cardiometabolic risk between normal weight and overweight/obese female college students.

Methods

Ten normal weight (NWCG) and 10 overweight/obese (AOG) individuals were recruited in this study. Both groups performed a regular 10,000 steps a day walk for 12 weeks. Their blood pressure, body mass index, waist-to-hip ratio, and blood lipid profiles were evaluated. Moreover, serum leptin and adiponectin levels were measured using an enzyme-linked immunosorbent assay.

Results

Our results revealed that triglyceride (TG), TG/high-density lipoprotein cholesterol (HDL-C) ratio and leptin were significantly reduced in the AOG group after the 12-week walking intervention. However, total cholesterol, HDL-C, and adiponectin/leptin ratio were significantly increased in the AOG group. There was little or no change in these variables in the NWCG group after the 12-week walking intervention.

Conclusions

Our study demonstrated that a 12-week walking intervention may help improve cardiorespiratory fitness and obesity-associated cardiometabolic risk by decrease resting heart rate, modulating blood lipid profiles, and inducing adipokine alterations in obese individuals. Therefore, our research encourages obese young adults to improve their physical health by participating in a 12-week walking program of 10,000 steps a day.

Assessment of physical fitness during pregnancy: validity and reliability of fitness tests, and relationship with maternal and neonatal health - a systematic review

Objectives

To systematically review studies evaluating one or more components of physical fitness (PF) in pregnant women, to answer two research questions: (1) What tests have been employed to assess PF in pregnant women? and (2) What is the validity and reliability of these tests and their relationship with maternal and neonatal health?

Design

A systematic review.

Data sources

PubMed and Web of Science.

Eligibility criteria

Original English or Spanish full-text articles in a group of healthy pregnant women which at least one component of PF was assessed (field based or laboratory tests).

Results

A total of 149 articles containing a sum of 191 fitness tests were included. Among the 191 fitness tests, 99 (ie, 52%) assessed cardiorespiratory fitness through 75 different protocols, 28 (15%) assessed muscular fitness through 16 different protocols, 14 (7%) assessed flexibility through 13 different protocols, 45 (24%) assessed balance through 40 different protocols, 2 assessed speed with the same protocol and 3 were multidimensional tests using one protocol. A total of 19 articles with 23 tests (13%) assessed either validity (n=4), reliability (n=6) or the relationship of PF with maternal and neonatal health (n=16).

Conclusion

Physical fitness has been assessed through a wide variety of protocols, mostly lacking validity and reliability data, and no consensus exists on the most suitable fitness tests to be performed during pregnancy.

PROSPERO registration number

CRD42018117554.

Exercise in Pregnancy Increases Placental Angiogenin without Changes in Oxidative or Endoplasmic Reticulum Stress

PURPOSE

Despite immense research highlighting maternal-fetal benefits of exercise during pregnancy, there remain concerns that exercise may undermine placental function. Although maternal exercise has demonstrated favorable aerobic conditioning responses in the mother, it is not known whether maternal exercise promotes increased angiogenesis in the placenta, perhaps at the expense of impaired endoplasmic reticulum (ER) homeostasis and/or oxidative stress. We investigated if a mild (30% heart rate reserve) and/or moderate (70% heart rate reserve) exercise regime in healthy pregnant women affected placental markers of angiogenesis, ER stress, and oxidative stress. We hypothesized that the improved aerobic conditioning of mothers who exercise is beneficial to enhance placental angiogenesis and normal maternal-fetal outcomes.

METHODS

Placental tissues were collected within 1 h of delivery from a convenience sample of 29 healthy mothers of full-term infants. Twenty-one women participated in routine exercise from midgestation (16-20 wk) until term of either mild or moderate intensity, whereas eight sedentary women served as controls.

RESULTS

No differences were identified between groups including gestational length, fetal-placental weight ratio, or APGAR scoring. All exercisers exhibited a significant 20-fold increase in the mRNA (as assessed by quantitative real-time polymerase chain reaction) and a 10-fold increase in the protein expression of angiogenin (e.g., ANG1) in the placenta. However, in both exercising groups, no increases in placental markers (i.e., HIF1α, VEGF), ER stress (i.e., spliced XBP1, ATF4, ATF6, CHOP, and BAX), or oxidative stress (i.e., SOD1, SOD2) were observed.

CONCLUSIONS

Overall, our study suggests that mild- and moderate-intensity exercise increases angiogenesis but does not increase placental oxidative or ER stress in healthy pregnancies, bolstering support for routine exercise as a part of standard care in pregnant women. Future studies are warranted to investigate the potential benefits of exercise on ANG1 in pathological pregnancies.

Prenatal Exercise and Cardiovascular Health (PEACH) Study: Impact on Muscle Sympathetic Nerve (Re)Activity

PURPOSE

Women who develop gestational hypertension have evidence of elevated muscle sympathetic nerve activity (MSNA) in early pregnancy, which continues to rise after diagnosis. Exercise has been shown to play a preventative role in the development of gestational hypertension and has been shown to reduce resting and reflex MSNA in nonpregnant populations. We sought to investigate whether aerobic exercise affected the sympathetic regulation of blood pressure between the second and third trimesters of pregnancy.

METHODS

We conducted a randomized controlled trial of structured aerobic exercise (n = 31) compared with no intervention (control, n = 28) beginning at 16-20 wk and continuing until 34-36 wk of gestation (NCT02948439). Women in the exercise group were prescribed aerobic activity at 50%-70% of their heart rate reserve, on 3-4 d·wk-1 for 25-40 min with a 5-min warm-up and 5-min cool-down (i.e., up to 160 min total activity per week). At preintervention and postintervention assessments, data from ~10 min of quiet rest and a 3-min cold pressor test were analyzed to determine sympathetic nervous system activity and reactivity.

RESULTS

MSNA was obtained in 51% of assessments. Resting MSNA burst frequency and burst incidence increased across gestation (main effect of gestational age, P = 0.002). Neurovascular transduction was blunted in the control group (P = 0.024) but not in exercisers (P = 0.873) at the postintervention time point. Lastly, MSNA reactivity during the cold pressor test was not affected by gestational age or exercise (P = 0.790, interaction).

CONCLUSIONS

These data show that exercise attenuates both the rise in MSNA and the blunting of neurovascular transduction. This may partially explain the lower risk of developing gestational hypertension in women who are active during their pregnancies.

Effectiveness of a Virtual Exercise Program During COVID-19 Confinement on Blood Pressure Control in Healthy Pregnant Women

BACKGROUND

The situation caused by COVID-19 has led to movement restrictions for the majority of the population due to the confinement established by the health authorities. This new situation has changed people's habits and significantly affected the pregnant population. Decreased exercise and increased psychophysical stress are associated with excessive weight gain, diabetes, and gestational cardiovascular complications that affect the mother, fetus, and newborn. Recent research shows that the dynamics of maternal blood pressure is one of the most important control factors during pregnancy. Thus, prevention of these type of pathologies through interventions without maternal-fetal risks is important.

OBJECTIVES

To examine the influence of a virtual exercise program on maternal blood pressure during pregnancy.

MATERIALS AND METHODS

A randomized clinical trial design was used (NCT04563065). Data from 72 pregnant women without obstetric contraindications under confinement conditions in the Madrid area were collected. Women were randomly assigned to the intervention (IG) or control group (CG). They previously signed informed consent forms. A moderate exercise program was performed as an intervention from 8-10 to 38-39 weeks of pregnancy. Systolic (SBP) and diastolic (DBP) maternal blood pressure were measured during the first, second and third trimesters of pregnancy, as well as before and immediately after delivery in both study groups.

RESULTS

No differences in systolic and diastolic blood pressure during the first, second and third trimesters were found between groups. Significant differences in SBP were found immediately before delivery (IG = 119.83 ± 10.16 vs. CG = 125.6 ± 10.91; p = 0.047) and immediately after delivery (IG = 115.00 ± 11.18 vs. CG = 122.24 ± 15.71; p = 0.045).

CONCLUSIONS

Results show lower SBP values for the IG during delivery than CG. A virtual exercise program throughout pregnancy during COVID-19 confinement can help to control systolic blood pressure before and immediately after delivery in healthy pregnant women.

To HIIT or not to HIIT? The question pregnant women may be searching for online: a descriptive observational study

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.

Body composition helps: Differences in energy expenditure between pregnant and nonpregnant females

OBJECTIVES

Human pregnancy is associated with important physiological changes that usually increase energetic requirements. However, great variability exists in the costs and mechanisms required to bear pregnancy. Since body mass (BM) and composition are modified during gestation, it is of great interest to compare the influence of BM on energy expenditure (EE) in pregnant and nonpregnant females.

METHODS

BM, body composition, and EE of 77 volunteers (35 pregnant and 42 nonpregnant females) were measured. The pregnant volunteers completed two measurement rounds at 28 and 32 gestation weeks. Differences on the measured parameters were sought, and comparison of regression lines was computed to test how BM affected the EE of the volunteers.

RESULTS

BM and body composition parameters are significantly higher in pregnant females, but EE is not statistically different. Pregnant females have a larger percentage of fat mass, but lower percentage of fat-free mass (FFM). The EE per kg of FFM is similar in both groups. Comparison of regression lines shows that pregnancy does not change the relationship between BM and EE, but for similar BM pregnant females expend less energy than nonpregnant females.

CONCLUSIONS

We propose that their larger percentage of passive body tissues is the reason why pregnant females expend less energy than nonpregnant females of similar BM, without changing the scaling of EE on BM. Thus, pregnancy could not be as energetically constraining as usually assumed, with important consequences for human reproductive ecology.

Walking in pregnancy and prevention of insomnia in third trimester using pedometers: study protocol of Walking_Preg project (WPP). A randomized controlled trial

BACKGROUND

Previous studies in pregnancy have not focused in evaluating the effect of walking during pregnancy and prevention of insomnia. Our general objective is to determine the effect of a walking program in preventing the appearance of insomnia in the third trimester of pregnancy, increasing sleep quality and improving quality of life throughout pregnancy.

METHODS

Randomized Controlled trial in parallel in healthy sedentary pregnant women (n = 265), Walking_Preg Project (WPP), from university hospital in Granada, Spain. At 12th gestational week (GW), they will be invited to participate and randomly assigned to one of the three arms of study: the intervention group I1 (pedometer, goal of 11,000 steps/day), intervention group I2 (pedometer, no goal) and control (no pedometer). Duration of intervention: 13-32 GW. At 12th, 19th and 31st GW the average steps/day will be measured in groups I1 and I2. At 13th, 20th and 32nd GW, Athens Insomnia Scale (AIS), Pittsburgh Sleep Quality Index (PSQI), Adherence to Mediterranean Diet (AMD), physical activity (short IPAQ), quality of life (PSI), and consumption of toxic substances (caffeine, illegal drugs, alcohol and tobacco) will be collected. Student t test or Mann-Whitney U will be used to compare 19th and 31st GW mean of daily steps between I1 and I2 groups. To compare differences between groups in terms of frequency of insomnia/quality of life for each trimester of pregnancy, Pearson's Chi-square test or Fisher's exact test will be used. To determine differences in hours of sleep and quality of sleep throughout each trimester of pregnancy, analysis of variance or Friedman test will be used. McNemar-Bowker test will be used to assess differences in life quality in pre-post analyses in the 3 arms. We will use Stata 15 statistical software.

DISCUSSION

promoting walking in second half of pregnancy through use of pedometer and health pre-registration of a goal to be achieved -'10,000-11,000 steps a day'- should prevent appearance of insomnia in third trimester, will increase sleep quality and quality of life in pregnant women.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03735381 . Registered 8th November, 2018.

Level of physical activity and other maternal characteristics during the third trimester of pregnancy and its association with birthweight at term in South Ethiopia: A prospective cohort study

Birthweight continues to be the leading infant health indicator and the main focus of infant health policy. Low birthweight babies are at a higher risk of mortality and morbidity in most low-income countries. However, the physical activity level of pregnant women and its association with low birthweight is not well studied in Ethiopia. To address the above gap, we aimed to examine the maternal physical activity level and other characteristics during the third trimester and its association with birthweight at term in South Ethiopia. A community-based prospective cohort study was conducted among 247 randomly selected women in their third trimester of pregnancy. We measured the physical activity level using the Global Physical Activity Questionnaire, which included the type and level of various categories of activities. Anthropometric measurements of mothers were taken following standard procedures, and birthweight was recorded within 72 hours of delivery. To identify the effect of physical activity level and other maternal characteristics on low birthweight, we performed a multivariable logistic regression analysis. Overall, 111 (47.2%) mothers were engaged in vigorous physical activities during third trimester. The incidence of low birthweight was 21.6% and 9.68% among newborns of mothers who engaged in vigorous and moderate or low physical activity, respectively. The incidence of low birthweight at term was significantly associated with vigorous physical activity [adjusted odds ratio (AOR) = 2.48; 95% confidence interval (CI): 1.01–6.09], prolonged standing [AOR = 3.37; 95% CI: 1.14–9.93], and squatting [AOR = 2.61; 95% CI: 1.04–6.54)] during the third trimester of pregnancy. The vast majority of pregnant women were engaged in vigorous physical activities in their third trimester. Engagement in vigorous physical activity, standing for longer hours, and squatting were the major contributors to low birthweight at term. Hence, focused counseling should be conducted to reduce vigorous physical activity, standing, and squatting during the third trimester among pregnant women.

The effects of vigorous intensity exercise in the third trimester of pregnancy: a systematic review and meta-analysis

Background

Fetal growth is dependent upon utero-placental vascular supply of oxygen and nutrients from the mother and has been proposed to be compromised by vigorous intensity exercise in the third trimester. The aim of this systematic review was to investigate the effects of vigorous intensity exercise performed throughout pregnancy, on infant and maternal outcomes.

Methods

Electronic searching of the PubMed, Medline, EMBASE, Cochrane Library, Web of Science and CINAHL databases was used to conduct the search up to November 2018. Study designs included in the systematic review were randomised control trials, quasi-experimental studies, cohort studies and case-control studies. The studies were required to include an intervention or report of pregnant women performing vigorous exercise during gestation, with a comparator group of either lower intensity exercise or standard care.

Results

Ten cohort studies (n = 32,080) and five randomized control trials (n = 623) were included in the systematic review (n = 15), with 13 studies included in the meta-analysis. No significant difference existed in birthweight for infants of mothers who engaged in vigorous physical activity and those who lacked this exposure (mean difference = 8.06 g, n = 8006). Moreover, no significant increase existed in risk of small for gestational age (risk ratio = 0.15, n = 4504), risk of low birth weight (< 2500 g) (risk ratio = 0.44, n = 2454) or maternal weight gain (mean difference = − 0.46 kg, n = 1834). Women who engaged in vigorous physical activity had a small but significant increase in length of gestational age before delivery (mean difference = 0.21 weeks, n = 4281) and a small but significantly reduced risk of prematurity (risk ratio = − 0.20, n = 3025).

Conclusions

Findings from this meta-analysis indicate that vigorous intensity exercise completed into the third trimester appears to be safe for most healthy pregnancies. Further research is needed on the effects of vigorous intensity exercise in the first and second trimester, and of exercise intensity exceeding 90% of maximum heart rate.

Trial registration

PROSPERO trial registration CRD42018102109.

Electronic supplementary material

The online version of this article (10.1186/s12884-019-2441-1) contains supplementary material, which is available to authorized users.

Assessment of neighborhood street characteristics related to physical activity in the Lower Mississippi Delta

Background: Physical activity levels were low for pregnant and postpartum participants in a diet and physical activity intervention. To explore micro level characteristics of participants'neighborhoods related to physical activity, an ancillary study was conducted. Methods: This cross-sectional study encompassed the neighborhood street segments of women participating in a diet and physical activity intervention that was conducted in the Lower Mississippi Delta. A neighborhood was defined as all street segments within one-fourth walking mile of a participant's home address. Street segments were measured using the Rural Active Living Assessment's Street Segment Assessment tool. In the field and on foot, raters measured street segments using neighborhood maps with segments identified. Results: Mean street segment length was 0.22 miles (SD = 0.14). All segments had flat terrain with residential (98%), open spaces (74%), and public/civic (34%) as the most prevalent land uses. Almost three-fourths of segments did not have any sidewalks (69%), sidewalk buffers or defined shoulders (73%), crosswalks or pedestrian signage (69%), or posted speed limits (74%).However, 88% had stop signs and almost all (96%) had street lighting and were paved multi lane roads (95%) with low traffic volume (90%). Most residential structures present were single family detached homes (95%) and the most common public/civic and commercial structures were churches (24%) and convenience stores (9%), respectively. Almost all of the street segments were rated as walk able (99%) and aesthetically pleasing (94%). Conclusion: Neighborhood street segments surrounding Delta Healthy Sprouts participants'homes were walk able and aesthetically pleasing. However, safety features such as sidewalks,pedestrian signage, and posted speed limit signs were lacking. To address these inadequate pedestrian safety features, infrastructure changes are needed for small rural towns.

Association of sedentary time and physical activity during pregnancy with maternal and neonatal birth outcomes. The GESTAFIT Project

AIM

(a) To analyse the association of objectively measured sedentary time (ST) and physical activity (PA) during early second trimester of pregnancy with maternal and neonatal birth outcomes; (b) to explore if ST and PA differ between women with vaginal or caesarean section deliveries.

METHODS

Ninety-four Caucasian pregnant women (32.9 ± 4.6 years old) participated in this prospective longitudinal study. Triaxial accelerometers were used to assess ST and PA intensity levels for seven consecutive days during second trimester of pregnancy. Birth data were collected from the obstetric medical records. Umbilical cord arterial and venous blood gas (pH, partial pressure of carbon dioxide and oxygen, and oxygen saturation) were analysed after birth.

RESULTS

After adjusting for potential confounders, greater ST was associated with higher arterial and venous cord blood partial pressure of carbon dioxide and more acidic arterial and venous pH (all, P < 0.01). Moderate PA, moderate-to-vigorous PA (MVPA), total PA and steps per day were positively associated with arterial cord blood oxygen saturation (all P < 0.05). Steps per day were inversely associated with gestational age at birth (P < 0.01), and duration of first stage of labor (P < 0.05). Total and light PA were associated with a more alkaline pH in umbilical vein (all, P < 0.01). Vigorous PA was inversely associated with the Apgar score (P < 0.01). No significant differences were observed in ST and PA levels between women with vaginal and women with caesarean section deliveries (all, P > 0.10).

CONCLUSION

Increasing PA and decreasing ST during pregnancy might promote better maternal and neonatal birth markers.

Improving Prenatal Care for Minority Women

Since the inception of prenatal care in the early 1900s, the focus of care has been on risk reduction rather than on health promotion. Prenatal care began as individualized care, but more recently group prenatal care has been shown to be very successful in improving birth outcomes. For all women, an emphasis on improving health behaviors is important at this critical time while women are engaging regularly with the healthcare system. An emphasis on mental health promotion may decrease some of the disparities in birth outcomes that are well documented between minority and majority women, as minority women are known to experience increased levels of stress, anxiety, and depression. Providing support for pregnant women and incorporating knowledge and skills through prenatal care may promote both physical and mental health in minority women.

Components of Exercise Prescription and Pregnancy

Physicians should discuss decreasing sedentary time and behavior with their pregnant patients to assist sedentary women to become more active using light activities. Medical screening before engaging or continuing in a moderate aerobic exercise program is vital to ensure a low-risk pregnancy. The FITT principle is important to use in prescription that suggests: Frequency (3 to 4 times per week), Intensity (appropriate target heart rate zone, rating of perceived exertion scale, or the talk test), Time (start at 15 min progressing to 30 min), and Type (moving large muscles groups such as walking, swimming, and cycling) of physical activity.

Cerebral blood flow regulation, exercise and pregnancy: why should we care?

Cerebral blood flow (CBF) regulation is an indicator of cerebrovascular health increasingly recognized as being influenced by physical activity. Although regular exercise is recommended during healthy pregnancy, the effects of exercise on CBF regulation during this critical period of important blood flow increase and redistribution remain incompletely understood. Moreover, only a few studies have evaluated the effects of human pregnancy on CBF regulation. The present work summarizes current knowledge on CBF regulation in humans at rest and during aerobic exercise in relation to healthy pregnancy. Important gaps in the literature are highlighted, emphasizing the need to conduct well-designed studies assessing cerebrovascular function before, during and after this crucial life period to evaluate the potential cerebrovascular risks and benefits of exercise during pregnancy.

Short-term and long-term effects of submaximal maternal exercise on offspring glucose homeostasis and pancreatic function

Only a few studies have explored the effects of maternal exercise during gestation on adult offspring metabolism. We set out to test whether maternal controlled submaximal exercise maintained troughout all gestational periods induces persistant metabolic changes in the offspring. We used a model of 15-wk-old nulliparous female Wistar rats that exercised (trained group) before and during gestation at a submaximal intensity or remained sedentary (control group). At weaning, male offspring from trained dams showed reduced basal glycemia (119.7 ± 2.4 vs. 130.5 ± 4.1 mg/dl, P < 0.05), pancreas relative weight (3.96 ± 0.18 vs. 4.54 ± 0.14 g/kg body wt, P < 0.05), and islet mean area (22,822 ± 4,036 vs. 44,669 ± 6,761 μm(2), P < 0.05) compared with pups from control dams. Additionally, they had better insulin secretory capacity when stimulated by 2.8 mM glucose + 20 mM arginine compared with offspring from control dams (+96%, P < 0.05). At 7 mo of age, offspring from trained mothers displayed altered glucose tolerance (AUC = 15,285 ± 527 vs. 11,898 ± 988 mg·dl(-1)·120 min, P < 0.05) and decreased muscle insulin sensitivity estimated by the phosphorylated PKB/total PKB ratio (-32%, P < 0.05) and tended to have a reduced islet insulin secretory capacity compared with rats from control dams. These results suggest that submaximal maternal exercise modifies short-term male offspring pancreatic function and appears to have rather negative long-term consequences on sedentary adult offspring glucose handling.

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.

Sedentary behavior, gestational diabetes mellitus, and type 2 diabetes risk: where do we stand?

A substantial number of pregnancies are complicated by gestational diabetes mellitus (GDM) and up to 70 % of women with GDM go on to develop type 2 diabetes. Given the extensive body of research suggesting physical activity reduces the risk of type 2 diabetes, facilitating physical activity, and reducing sedentary time may be effective approaches to promote the health of women with a previous GDM diagnosis. Here, we discuss physical activity, exercise, and sedentary behavior, in the context of GDM and the potential for type 2 diabetes risk reduction.

Fetal and maternal metabolic responses to exercise during pregnancy

Pregnancy is characterized by physiological, endocrine and metabolic adaptations creating a pseudo-diabetogenic state of progressive insulin resistance. These adaptations occur to sustain continuous fetal requirements for nutrients and oxygen. Insulin resistance develops at the level of the skeletal muscle, and maternal exercise, especially activity involving large muscle groups improve glucose tolerance and insulin sensitivity. We discuss the maternal hormonal and metabolic changes associated with a normal pregnancy, the metabolic dysregulation that may occur leading to gestational diabetes mellitus (GDM), and the consequences to mother and fetus. We will then examine the acute and chronic (training) responses to exercise in the non-pregnant state and relate these alterations to maternal exercise in a low-risk pregnancy, how exercise can be used to regulate glucose tolerance in women at risk for or diagnosed with GDM. Lastly, we present key exercise guidelines to help maintain maternal glucose regulation and suggest future research directions.

Physical Activity Patterns and Factors Related to Exercise during Pregnancy: A Cross Sectional Study

Objective

To assess the physical activity levels of pregnant women and to examine the characteristics associated with the practice of exercise and the activities of daily living during pregnancy.

Methods

For this cross-sectional study, 1,279 women were recruited within 72 hours postpartum. They were interviewed about their socio-demographic data and obstetric history and were administered self-report questionnaires about exercise and daily physical activities during pregnancy. Data on the current pregnancy, labor, delivery, and newborn outcomes were collected from participants’ medical records. To analyze factors related to the practice of exercise, we used the student t-test, X², and odds ratio (OR), with a corresponding 95% confident interval (CI), followed by a multiple logistic regression. The significance level was 5%.

Results

Compared to the pre-pregnancy period, the prevalence of physical activity among participants was lower throughout pregnancy (20.1%) (p = 0.01). Half of the women interrupted practicing physical exercise due to pregnancy. The lowest prevalence of exercise was observed in the first (13.6%) and third trimesters (13.4%). Less than half of women received exercise guidance during prenatal care meetings (47.4%). Walking was the most commonly reported exercise, followed by water aerobics. Factors positively associated with exercise practice were higher educational level (OR= 1.82; CI 95% 1.28–2.60), primiparity (OR=1.49; CI 95% 1.07–2.07), exercising before pregnancy (OR= 6.45; CI 95% 4.64–8.96), and exercise guidance during prenatal care (OR=2.54; CI 95% 1.80–3.57). Mildly intense exercise and domestic activities were most frequently reported among pregnant women. There were no differences in maternal and perinatal outcomes between active and sedentary pregnant women.

Conclusion

The findings indicate that promoting physical activity remains a priority in public health policy, and women of childbearing age, especially those planning a pregnancy, should be encouraged to adopt an exercise routine or maintain an active lifestyle during pregnancy in order to avoid sedentary- and obesity-associated risks.

The efficacy of moderate-to-vigorous resistance exercise during pregnancy: a randomized controlled trial

OBJECTIVES

To assess the effect and safety of moderate-to-vigorous resistance exercise during pregnancy.

DESIGN

Randomized controlled study.

SETTING

Two antenatal clinics in Gothenburg, Sweden.

POPULATION

Ninety-two healthy pregnant women.

METHODS

The intervention was administered during gestational weeks 14-25. The intervention group received supervised resistance exercise twice a week, performed at an activity level equivalent to within moderate-to-vigorous (n = 51). The control group received generalized exercise recommendation, a home-based training program and a telephone follow up (n = 41).

MAIN OUTCOME MEASURES

Health-related quality of life, physical strength, pain, weight, blood pressure, functional status, activity level, and perinatal data.

RESULTS

Functional status deteriorated during the intervention in both groups and pain increased. Significant differences between the groups were obtained only for birthweight. Newborns delivered by women who underwent resistance exercise during pregnancy were significantly heavier than those born to control women; 3561 (±452) g vs. 3251 (±437) g (p = 0.02), a difference that disappeared when adjustment was made for gestational age (p = 0.059). Both groups showed normal health-related quality of life, blood pressure, and perinatal data.

CONCLUSIONS

These findings indicate that supervised, moderate-to-vigorous resistance exercise does not jeopardize the health status of healthy pregnant women or the fetus during pregnancy, but instead appears to be an appropriate form of exercise in healthy pregnancy.

A Program of Exercise Throughout Pregnancy. Is it Safe to Mother and Newborn?

Purpose.

The aim of the present study was to examine the influence of a program of moderate physical exercise throughout pregnancy on maternal and fetal parameters.

Design.

The study design was a randomized controlled trial.

Setting.

The study took place at the Hospital of Fuenlabrada in Madrid, Spain.

Sample.

Analyzed were 200 pregnant women (31.54 ± 3.86 years), all of whom had uncomplicated and singleton gestation. Of these subjects, 107 were allocated to the exercise group (EG) and 93 to the control group (CG).

Intervention.

Women from EG participated in a physical conditioning program throughout pregnancy, which included a total of 55- to 60-minute weekly sessions, 3 days per week.

Measures.

Pregnancy outcomes. Maternal: gestational age, weight gain, type of delivery, blood pressure during pregnancy, gestational diabetes (n/%). Fetal: birth weight, birth size, head circumference, Apgar score, pH of umbilical cord.

Analysis.

Student's unpaired t-test and χ2 test were used; p values of ≤ .05 indicated statistical significance. Cohen's d was used to determine the effect size.

Results.

There were significantly more pregnant women in the CG who gained excessive weight during their pregnancies than in the EG group (CG: N = 31, 35.6% versus N = 22, 21.2%; χ2 = 4.95; p =.02). The effect size was small (Phi value =.16). Other pregnancy outcome showed no differences between groups.

Conclusion.

A regular and moderate physical exercise program throughout pregnancy is not a risk to maternal and fetal well-being, and it helps to control excessive weight gain.

Physiological and metabolic responses of late pregnant women to 40 min of steady-state exercise followed by an oral glucose tolerance perturbation

We examined the physiological and metabolic responses of 24 active late pregnant women to 40 min of vigorous (95% ventilatory threshold) steady-state treadmill exercise followed by a metabolic perturbation [oral glucose tolerance test (OGTT), 75 g] after exercise. Heart rate and respiratory measures were taken throughout exercise, and blood samples were collected during exercise and every 30 min during the 2-h OGTT. Values were compared with those for a group of physically active nonpregnant women ( n = 16) in the luteal phase of the menstrual cycle. Although late pregnant women were heavier, they performed the same work rate (182 vs. 208 W, P > 0.05), with the same oxygen pulse, but responded to the exercise with a blunted heart rate and relative oxygen consumption, with less carbon dioxide expired, possibly due to pregnancy-related adaptations in heart efficiency. Resting glucose concentrations were the same between groups, but by 40 min of exercise (3.8 ± 0.1 vs. 4.6 ± 0.1 mmol/l) and into 15 min of recovery (4.3 ± 0.2 vs. 5.0 ± 0.1 mmol/l), glucose concentrations were diminished in late pregnant women ( P ≤ 0.05, respectively). The pregnancy-induced delay of glucose uptake was seen in response to the postexercise OGTT compared with the nonpregnant women, but insulin sensitivity (ISI) remained (7.4 ± 0.9 vs. 9.7 ± 1.4 ISI, P > 0.05, respectively), with the preservation of the sensitivity of lipolysis inhibition of nonesterified free fatty acids to insulin. These adaptations may be fetoprotective, because our research suggests that 40 min of continuous treadmill exercise is well tolerated by physically active pregnant women. No adverse effects on birth outcome (3.53 ± 0.08 kg birth weight; 39.6 ± 0.33 wk gestational age) were observed.