Measuring energy expenditure in habitually active and sedentary pregnant women

Quality Evaluation of Free-living Validation Studies for the Assessment of 24-Hour Physical Behavior in Adults via Wearables: Systematic Review

Background

Wearable technology is a leading fitness trend in the growing commercial industry and an established method for collecting 24-hour physical behavior data in research studies. High-quality free-living validation studies are required to enable both researchers and consumers to make guided decisions on which study to rely on and which device to use. However, reviews focusing on the quality of free-living validation studies in adults are lacking.

Objective

This study aimed to raise researchers’ and consumers’ attention to the quality of published validation protocols while aiming to identify and compare specific consistencies or inconsistencies between protocols. We aimed to provide a comprehensive and historical overview of which wearable devices have been validated for which purpose and whether they show promise for use in further studies.

Methods

Peer-reviewed validation studies from electronic databases, as well as backward and forward citation searches (1970 to July 2021), with the following, required indicators were included: protocol must include real-life conditions, outcome must belong to one dimension of the 24-hour physical behavior construct (intensity, posture or activity type, and biological state), the protocol must include a criterion measure, and study results must be published in English-language journals. The risk of bias was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 tool with 9 questions separated into 4 domains (patient selection or study design, index measure, criterion measure, and flow and time).

Results

Of the 13,285 unique search results, 222 (1.67%) articles were included. Most studies (153/237, 64.6%) validated an intensity measure outcome such as energy expenditure. However, only 19.8% (47/237) validated biological state and 15.6% (37/237) validated posture or activity-type outcomes. Across all studies, 163 different wearables were identified. Of these, 58.9% (96/163) were validated only once. ActiGraph GT3X/GT3X+ (36/163, 22.1%), Fitbit Flex (20/163, 12.3%), and ActivPAL (12/163, 7.4%) were used most often in the included studies. The percentage of participants meeting the quality criteria ranged from 38.8% (92/237) to 92.4% (219/237). On the basis of our classification tree to evaluate the overall study quality, 4.6% (11/237) of studies were classified as low risk. Furthermore, 16% (38/237) of studies were classified as having some concerns, and 72.9% (173/237) of studies were classified as high risk.

Conclusions

Overall, free-living validation studies of wearables are characterized by low methodological quality, large variability in design, and focus on intensity. Future research should strongly aim at biological state and posture or activity outcomes and strive for standardized protocols embedded in a validation framework. Standardized protocols for free-living validation embedded in a framework are urgently needed to inform and guide stakeholders (eg, manufacturers, scientists, and consumers) in selecting wearables for self-tracking purposes, applying wearables in health studies, and fostering innovation to achieve improved validity.

Physical Exertion Immediately Before Early Preterm Delivery: A Case-Crossover Study

BACKGROUND

Occupational exertion is associated with a higher risk of preterm delivery, although studies of leisure time activities generally document reduced risks. Less is known about the risk of preterm delivery immediately following episodes of moderate or heavy physical exertion.

METHODS

We conducted a case-crossover study of 722 women interviewed during their hospital stay for early preterm delivery, defined by a gestational age before 34 weeks, and after 20 weeks. Interviews occurred between March 2013 and December 2015 in seven hospitals in Lima, Peru.

RESULTS

The incidence rate ratio (RR) of early preterm delivery was 5.82-fold higher (95% confidence interval [CI] = 4.29, 7.36) in the hour following moderate or heavy physical exertion compared with other times and returned to baseline in the hours thereafter. The RR of early preterm delivery within an hour of physical exertion was lower for exertion at moderate intensity (RR = 2.43; 95% CI = 1.50, 3.96) than at heavy intensity (RR = 23.62; 95% CI = 15.54, 35.91; P-homogeneity < 0.001). The RR of early preterm delivery was lower in the hour following moderate physical exertion among women who habitually engaged in physical exertion >3 times per week in the year before pregnancy (RR = 1.56; 95% CI = 0.81, 3.00) compared with more sedentary women (RR = 6.91; 95% CI = 3.20, 14.92; P-homogeneity = 0.003).

CONCLUSIONS

Our study showed a heightened risk of early preterm delivery in the hour following moderate or heavy physical exertion.

The Behavioral Wellness in Pregnancy study: a randomized controlled trial of a multi-component intervention to promote appropriate weight gain

BACKGROUND

Adequate weight gain during pregnancy is important to both maternal and fetal outcomes. To date, randomized controlled trials have not been effective at increasing the proportion of women meeting gestational weight-gain guidelines.

OBJECTIVES

The aim of this study was to determine whether a multi-component behavioral intervention with a Registered Dietitian Nutritionist significantly improves the proportion of women who adhere to the 2009 Institute of Medicine weight-gain guidelines.

METHODS

Participants were randomly assigned to usual care (UC; n = 24) or intervention (n = 23) between 8 and 14 weeks of gestation. The intervention included a minimum of 6 one-on-one counseling sessions over ∼30 wk focusing on healthy diet and physical activity (PA) goals. In addition to the face-to-face visits, weekly communication via email supported healthy eating, PA, and appropriate weight gain. Gestational weight gain, PA, and diet were assessed at 8-14, 26-28, and 34-36 weeks of gestation; weight retention was measured 2 mo postpartum.

RESULTS

The proportion of women meeting the guidelines was significantly greater in those receiving the intervention than UC (60.8% compared with 25.0%, OR: 4.7; 95% CI: 1.3, 16.2; P = 0.019). Furthermore, 36.4% of the intervention women were at or below their prepregnancy weight at 2 mo postpartum compared with 12.5% in the UC group (P = 0.05).

CONCLUSIONS

A multi-component behavioral intervention improved adherence to the 2009 Institute of Medicine weight-gain guidelines. This trial was registered with clinicaltrials.gov as NCT02168647.

Physical Activity Questionnaires for Pregnancy: A Systematic Review of Measurement Properties

Background

In order to assess physical activity (PA) during pregnancy, it is important to choose the instrument with the best measurement properties.

Objectives

To systematically summarize, appraise, and compare the measurement properties of all self-administered questionnaires assessing PA in pregnancy.

Methods

We searched PubMed, Embase, and SPORTDiscus with the following inclusion criteria: (i) the study reported at least one measurement property (reliability, criterion validity, construct validity, responsiveness) of a self-administered questionnaire; (ii) the questionnaire intended to measure PA; (iii) the questionnaire was evaluated in healthy pregnant women; and (iv) the study was published in English. We evaluated results, quality of individual studies, and quality of evidence using a standardized checklist (Quality Assessment of Physical Activity Questionnaires [QAPAQ]) and the GRADE (Grading of Recommendation, Assessment, Development, and Evaluation) approach.

Results

Seventeen articles, reporting 18 studies of 11 different PA questionnaires (17 versions), were included. Most questionnaire versions showed insufficient measurement properties. Only the French and Turkish versions of the Pregnancy Physical Activity Questionnaire (PPAQ) showed both sufficient reliability and construct validity. However, all versions of the PPAQ pooled together showed insufficient construct validity. The quality of individual studies was usually high for reliability but varied considerably for construct validity. Overall, the quality of evidence was very low to moderate.

Conclusions

We recommend the PPAQ to assess PA in pregnancy, although the pooled results revealed insufficient construct validity. The lack of appropriate standards in data collection and processing criteria for objective devices in measuring PA during pregnancy attenuates the quality of evidence. Therefore, research on the validity of comparison instruments in pregnancy followed by consensus on validation reference criteria and standards of PA measurement is needed.

Electronic supplementary material

The online version of this article (10.1007/s40279-018-0961-x) contains supplementary material, which is available to authorized users.

Progressive changes in walking kinematics throughout pregnancy-A follow up study

BACKGROUND

Progressive weight gain and changes in its distribution following pregnancy may be challenging for the gravidas' ability to move in a stable way.

RESEARCH QUESTION

How is gait kinematics changing throughout pregnancy and to what extend is it affected by physical activity level and energy balance?

METHODS

30 women were enrolled. Three experimental sessions were arranged according to the same protocol in the first, second and third trimesters of pregnancy. Walking kinematics at a self-selected speed was registered. The total physical activity (TPA) was assessed from the subjects' questionnaires. Energy balance ('positive', 'balanced' or 'negative') was estimated as the difference between dietary energy intake and energy expenditure during 7 days.

RESULTS

No significant differences were found in the spatiotemporal variables between experimental sessions. However, the gait analysis revealed significant increments in the single support and base of support (BoS) measures. Generally, the sagittal plane mobility of the lower limb joints did not differ, however, the pelvic tilt increased in late pregnancy. The hip and pelvis angles were significantly different over the gait cycle throughout gestation. The 'balanced' energy was dominant in the first trimester although the relative number of participants with negative balance increased over pregnancy. Overall, gait parameters were independent of the energy balance. However, significant correlation was found between gait parameters, such as BoS, velocity, stride length, and TPA in the advanced pregnancy.

SIGNIFICANCE

The longitudinal assessment of walking kinematics demonstrates few changes adopted to accommodate for pregnancy. The enlargement of BoS is considered as a strategy to provide safety and stability. The increased pelvic tilt is likely to compensate for changes in the body mass distribution. The physical activity correlates with the BoS measures and stride length and thus may be important for enhancing gait stability.

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.

Physical Activity Device Reliability and Validity during Pregnancy and Postpartum

Current physical activity (PA) recommendations for women experiencing a normal pregnancy reflect recent research showing numerous health benefits for mother and offspring. However, few studies have evaluated PA devices' reliability and validity during pregnancy, because anatomical and physiological changes throughout gestation could affect an instrument's accuracy.

PURPOSE

This study aimed to determine the reliability and validity of PA devices worn on the hip, ankle, and triceps during pregnancy and postpartum.

METHODS

Thirty-three women performed six activities of daily living and one treadmill walk at approximately 21 and 32 wk of pregnancy, and 12 wk postpartum. There were two visits at each time period, 1 wk apart. Energy expenditure (oxygen consumption) was measured by using indirect calorimetry (IC; criterion measure), whereas PA was quantified by using accelerometers and pedometers placed at the right hip and ankle and left triceps. Interclass reliability and monitor validity compared with IC in relative (mL·kg·min) terms were calculated using Pearson correlation. Both multitrial and single-trial intraclass reliabilities (ICC) were estimated using ANOVA to assess monitor reliability at each time period. SEM values were calculated in relative terms for each time period.

RESULTS

The reliability of the devices was moderate/strong because 66% of the Pearson correlations were between 0.6 and 1.0. Multitrial ICC values were largely in the moderate/strong range because 38% of the ICC values were between 0.6 and 0.79 and 50% were between 0.8 and 1.0. The SEM values for each device between visits ranged from 7% to 23% of the mean values. Comparison between IC and devices showed that 40% and 46% of the validity coefficients were between 0.4 and 0.59 and between 0.6 and 0.79, respectively.

CONCLUSIONS

PA devices show moderate/strong reliability and moderate validity for measuring PA during pregnancy and postpartum.

Improving pregnancy outcome in obese women: the UK Pregnancies Better Eating and Activity randomised controlled Trial

Background

Obesity in pregnancy is associated with insulin resistance, which underpins many common complications including gestational diabetes mellitus (GDM) and fetal macrosomia.

Objectives

To assess the effect of a complex behavioural intervention based on diet and physical activity (PA) on the risk of GDM and delivery of a large-for-gestational age (LGA) infant.

Design

Three phases: (1) the development phase, (2) the pilot study and (3) a multicentre randomised controlled trial (RCT) comparing a behavioural intervention to improve glycaemic control with standard antenatal care in obese pregnant women. A cost–utility analysis was undertaken to estimate the cost-effectiveness of the health training (intervention) over and above standard care (control).

Setting

Pilot study: antenatal clinics in four inner-city UK hospitals. RCT: eight antenatal clinics in eight UK inner-city hospitals.

Participants

Women were eligible for inclusion if they had a body mass index of ≥ 30 kg/m2, were pregnant with a single fetus and at 15+0to 18+6weeks’ gestation, were able to give written informed consent and were without predefined disorders.

Intervention

The intervention comprised an initial session with a health trainer, followed by eight weekly sessions. Dietary advice recommended foods with a low dietary glycaemic index, avoidance of sugar-sweetened beverages and reduced saturated fats. Women were encouraged to increase daily PA.

Main outcome measures

Development phase: intervention development, acceptability and optimal approach for delivery. Pilot study: change in dietary and PA behaviours at 28 weeks’ gestation. RCT: the primary outcome of the RCT was, for the mother, GDM [as measured by the International Association of the Diabetes and Pregnancy Study Groups (IADPSG)’s diagnostic criteria] and, for the infant, LGA delivery (i.e. customised birthweight ≥ 90th centile for gestational age).

Results

Development phase: following a literature meta-analysis, a study of dietary intention questionnaires and semistructured interviews, an intervention based on behavioural science was developed that incorporated optimal and acceptable methods for delivery. Pilot study: the pilot study demonstrated improvement in dietary behaviours in the intervention compared with the standard care arm but no increase in objectively measured PA. Process evaluation demonstrated feasibility and general acceptability. RCT: the RCT showed no effect of the intervention on GDM in obese pregnant women or the number of deliveries of LGA infants. There was a reduction in dietary glycaemic load (GL) and reduced saturated fat intake, an increase in PA and a modest reduction in gestational weight gain, all secondary outcomes. Lower than expected was the number of LGA infant deliveries in all women, which suggested that universal screening for GDM with IADPSG’s diagnostic criteria, and subsequent treatment, may reduce the number of deliveries of LGA infants. According to the cost–utility analysis, the estimated probability that the UK Pregnancies Better Eating and Activity Trial (UPBEAT) behavioural intervention is cost-effective at the £30,000/quality-adjusted life-year willingness-to-pay threshold was 1%.

Limitations

Included the high refusal rate for participation and self-reported assessment of diet and PA.

Conclusions

The UPBEAT intervention, an intense theoretically based intervention in obese pregnant women, did not reduce the risk of GDM in women or the number of LGA infant deliveries, despite successfully reducing the dietary GL. Based on total cost to the NHS provider and health gains, the UPBEAT intervention provided no supporting evidence to suggest that the intervention represents value for money based on the National Institute for Health and Care Excellence benchmarks for cost-effectiveness.

Future work

Alternative strategies for reducing the risk of GDM in obese pregnant women and the number of LGA infant deliveries should be considered, including development of clinically effective interventions to prevent obesity in women of reproductive age, of clinically effective interventions to reduce weight retention following pregnancy and of risk stratification tools in early pregnancy.

Trial registration

Current Controlled Trials ISRCTN89971375 and UK Clinical Research Network Portfolio 5035.

Funding

This project was funded by the NIHR Programme Grant for Applied Research programme and will be published in full inProgramme Grants for Applied Research, Vol. 5, No. 10. See the NIHR journals library website for further project information. Contributions to funding were also provided by the Chief Scientist Office CZB/4/680, Scottish Government Health Directorates, Edinburgh; Guys and St Thomas’ Charity, Tommy’s Charity (Lucilla Poston, Annette L Briley, Paul T Seed) and the NIHR Biomedical Research Centre at Guy’s and St Thomas’ NHS Foundation Trust and King’s College London, UK and the Academy of Finland, Finland. Keith M Godfrey was supported by the National Institute for Health Research through the NIHR Southampton Biomedical Research Centre. Lucilla Poston and Keith M Godfrey were supported by the European Union’s Seventh Framework Programme (FP7/2007-2013), project EarlyNutrition under grant agreement number 289346.

The Effect of Breakfast Prior to Morning Exercise on Cognitive Performance, Mood and Appetite Later in the Day in Habitually Active Women

Pre-exercise nutritional practices for active females exercising for mood, cognitive and appetite benefits are not well established. Results from an initial field pilot study showed that higher energy intake at breakfast was associated with lower fatigue and higher overall mood and alertness post-exercise (all p < 0.05). In a follow-up, randomised, controlled trial, 24 active women completed three trials in a balanced, cross-over design. At 0815 h participants completed baseline cognitive tasks, mood and appetite visual analogue scales (VAS) and were administered a cereal breakfast (providing 118 or 236 kcal) or no breakfast. After 45 min, they completed a 30 min run at 65% heart rate reserve (HRR). Parameters were re-assessed immediately after exercise, then hourly until lunch (~1240 h), immediately post-lunch and at 1500 and 1900 h via a mobile phone. Breakfast enhanced feelings of relaxation before lunch (p < 0.05, d > 0.40), though breakfast was detrimental for working memory mid-afternoon (p = 0.019, d = 0.37) and mental fatigue and tension later in the day (all p < 0.05, d > 0.038). Breakfast was also beneficial for appetite control before lunch irrespective of size (all p < 0.05, d > 0.43). These data provide information on pre-exercise nutritional practices for active females and suggest that a small breakfast eaten prior to exercise can benefit post-exercise mood and subjective appetite ratings.

Physical activity, sedentary behaviour and fetal macrosomia in uncomplicated pregnancies: a prospective cohort study

OBJECTIVE

to explore maternal energy balance, incorporating free living physical activity and sedentary behaviour, in uncomplicated pregnancies at risk of macrosomia.

METHODS

a parallel-group cross-sectional analysis was conducted in healthy pregnant women predicted to deliver infants weighing ≥ 4000 g (study group) or < 4000 g (control group). Women were recruited in a 1:1 ratio from antenatal clinics in Northern Ireland. Women wore a SenseWear(®) Body Media Pro3 physical activity armband and completed a food diary for four consecutive days in the third trimester. Physical activity was measured in Metabolic Equivalent of Tasks (METs) where 1 MET = 1 kcal per kilogram of body weight per hour. Analysis of covariance (ANCOVA) was employed using the General Linear Model to adjust for potential confounders.

FINDINGS

of the 112 women recruited, 100 complete datasets were available for analysis. There was no significant difference in energy balance between the two groups. Intensity of free living physical activity (average METs) of women predicted to deliver macrosomic infants (n = 50) was significantly lower than that of women in the control group (n = 50) (1.3 (0.2) METs (mean, standard deviation) versus 1.2 (0.2) METs; difference in means -0.1 METs (95% confidence interval: -0.19, -0.01); p = 0.021). Women predicted to deliver macrosomic infants also spent significantly more time in sedentary behaviour (≤ 1 MET) than the control group (16.1 (2.8) hours versus 13.8 (4.3) hours; 2.0 hours (0.3, 3.7), p = 0.020).

KEY CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

although there was no association between predicted fetal macrosomia and energy balance, those women predicted to deliver a macrosomic infant exhibited increased sedentary behaviour and reduced physical activity in the third trimester of pregnancy. Professionals caring for women during pregnancy have an important role in promoting and supporting more active lifestyles amongst women who are predicted to deliver a macrosomic infant given the known associated risks.

Relationship of Past-Pregnancy Physical Activity and Self-efficacy With Current Physical Activity and Postpartum Weight Retention

Life events unique to the perinatal period may place a woman at greater risk for decreased physical activity and increased postpartum weight retention (PPWR). Study purposes were to determine a) the relationship between women’s postpartum self-efficacy (SE) to overcome perceived barriers to exercise with current and past pregnancy leisure-time physical activity (LTPA), and b) the relationship between LTPA and PPWR. A Modifiable Activity Questionnaire was used to assess current and past pregnancy LTPA (Met*h/wk) at 20 and 32 weeks gestation and 12 weeks postpartum. Current barriers to LTPA and SE were assessed via the Perceived Barriers Efficacy Questionnaire. Top three barrier values were averaged to obtain an overall SE score for participants (N=30). Pearson correlations were run between LTPA, PPWR and SE scores. ANOVA was used to compare PPWR between women who did and did not meet LTPA guidelines of 7.5 MET*h/wk. The top three barriers to LTPA were time, motivation, and childcare. Positive correlations (p≤0.01) were found between SE levels and LTPA at all time periods of interest. LTPA was inversely related to PPWR. Relationships between SE, LTPA, and PPWR helped validate the need to promote perinatal PA, to aid long term weight management.

Developing a complex intervention for diet and activity behaviour change in obese pregnant women (the UPBEAT trial); assessment of behavioural change and process evaluation in a pilot randomised controlled trial

BACKGROUND

Complex interventions in obese pregnant women should be theoretically based, feasible and shown to demonstrate anticipated behavioural change prior to inception of large randomised controlled trials (RCTs). The aim was to determine if a) a complex intervention in obese pregnant women leads to anticipated changes in diet and physical activity behaviours, and b) to refine the intervention protocol through process evaluation of intervention fidelity.

METHODS

We undertook a pilot RCT of a complex intervention in obese pregnant women, comparing routine antenatal care with an intervention to reduce dietary glycaemic load and saturated fat intake, and increase physical activity. Subjects included 183 obese pregnant women (mean BMI 36.3 kg/m2).

RESULTS

Compared to women in the control arm, women in the intervention arm had a significant reduction in dietary glycaemic load (33 points, 95% CI -47 to -20), (p < 0.001) and saturated fat intake (-1.6% energy, 95% CI -2.8 to -0. 3) at 28 weeks' gestation. Objectively measured physical activity did not change. Physical discomfort and sustained barriers to physical activity were common at 28 weeks' gestation. Process evaluation identified barriers to recruitment, group attendance and compliance, leading to modification of intervention delivery.

CONCLUSIONS

This pilot trial of a complex intervention in obese pregnant women suggests greater potential for change in dietary intake than for change in physical activity, and through process evaluation illustrates the considerable advantage of performing an exploratory trial of a complex intervention in obese pregnant women before undertaking a large RCT.

TRIAL REGISTRATION

TRIAL REGISTRATION NUMBER

ISRCTN89971375.

Measuring physical activity in pregnancy: a comparison of accelerometry and self-completion questionnaires in overweight and obese women

OBJECTIVES

Increased physical activity in pregnancy may reduce the risk of gestational diabetes and pre-eclampsia, which occur more commonly in overweight and obese women. There is limited assessment of physical activity questionnaires in pregnancy. This study compares self-reported physical activity using two questionnaire methods with objectively recorded physical activity using accelerometry in overweight and obese pregnant women.

STUDY DESIGN

59 women with booking BMI≥25 kg/m(2) completed the Recent Physical Activity Questionnaire (RPAQ) and Australian Women's Activity Survey (AWAS) or recorded at least 3 days of accelerometry at median 12 weeks' gestation. Accelerometer thresholds of 100 counts/min and 1952 counts/min were used to define light and moderate or vigorous physical activity (MVPA) respectively.

RESULTS

48% of women were in their first pregnancy and 41% were obese. Median daily self-reported MVPA was significantly higher for both AWAS (127 min, p<0.001) and RPAQ (81 min, p<0.001) than that recorded by accelerometer (35 min). There was low or moderate correlation between questionnaire and accelerometer estimates of total active time (AWAS ρ=0.36, p=0.008; RPAQ ρ=0.53, p<0.001) but no significant correlation between estimates of time spent in MVPA.

CONCLUSIONS

These self-report questionnaires over-estimated MVPA and showed poor ability to discriminate women on the basis of MVPA. Accelerometry measurement was feasible and acceptable. Objective methods should be used where possible in studies measuring physical activity in pregnancy. Questionnaires remain valuable to define types of activity.

Physical activity energy expenditure and glucose control in pregnant women with type 1 diabetes: is 30 minutes of daily exercise enough?

OBJECTIVE

To describe activity patterns in pregnant women with type 1 diabetes and evaluate the impact of increased structured physical activity on glucose control.

RESEARCH DESIGN AND METHODS

Physical activity energy expenditure (PAEE) and glucose levels (continuous glucose monitoring) were measured in 10 pregnant women with type 1 diabetes (age 33.2 years, gestation 20 weeks, BMI 27.9 kg/m(2), diabetes duration 16.6 years, HbA1c 6.5% [48 mmol/mol], insulin pump duration 2.4 years) during a day at home (free-living) and during a 24-h visit incorporating controlled diet and structured physical activity with light intensity activity (three 20-min self-paced walks) and moderate intensity activity (two 50-min sessions of brisk treadmill walking). PAEE was evaluated through individually calibrated combined heart rate and movement sensing.

RESULTS

Free-living PAEE was comparable to that under controlled study conditions (3.8 and 5.1 kcal/kg/day, P = 0.241), with women achieving near to the recommended 30 min of moderate physical activity (median 27 min [interquartile range 14-68]). During the free-living period, more time was spent in light activity (10.3 vs. 7.2 h, P = 0.005), with less sedentary time (13.0 vs. 14.9 h, P = 0.047) and less moderate activity (27 vs. 121 min, P = 0.022). The free-living 24-h mean glucose levels by continuous glucose monitoring were significantly higher (7.7 vs. 6.0 mmol/L, P = 0.028). The effect of controlled diet and exercise persisted overnight, with significantly less time spent hyperglycemic (19 vs. 0%, P = 0.028) and less glucose variability (glucose SD 1.3 vs. 0.7 mmol/L, P = 0.022).

CONCLUSIONS

A controlled diet and structured physical activity program may assist women with type 1 diabetes in achieving optimal glucose control during pregnancy.

Physical activity during pregnancy: impact of applying different physical activity guidelines

Multiple guidelines and definitions of physical activity (PA) have been used to study the benefits of activity during pregnancy. The different guidelines lead to a wide range of prevalence estimates and this has led to conflicting reports about activity patterns during pregnancy. A longitudinal study was conducted to assess PA using a pattern-recognition monitor for a 7-day period at week 18 (n = 55) and week 35 (n = 66) of pregnancy. The amount of activity performed and the number of women meeting six different PA guidelines were evaluated. Adherence to PA guidelines ranged from 5 to 100% and 9 to 100% at weeks 18 and 35, respectively. All women achieved the 500 MET-minute guideline and nearly all women accumulated ≥150 minutes of weekly moderate-vigorous physical activity (MVPA) at both time points. Only 22% and 26% participated in ≥3 sessions of MVPA lasting ≥30 minutes at both time points and this further declined to 5% and 9% when the guideline was increased to ≥5 sessions of 30 minutes. The amount of PA during pregnancy varied drastically depending on which guideline was used. Further research is warranted to clearly identify the patterns of activity that are associated with healthy pregnancy outcomes.

Effect of intensive counselling on physical activity in pregnant women at high risk for gestational diabetes mellitus. A clinical study in primary care

OBJECTIVE

The level of physical activity (PA) of pregnant women in Finland is unknown. Even more limited is our knowledge of PA of women at high risk for gestational diabetes mellitus (GDM).

METHODS

The women (n=54) were randomly assigned to a lifestyle intervention group (n=27) including exercise advice by a physiotherapist six times during pregnancy or to a control group (n=27) without additional exercise advice. Outcomes of the present study were required sample size, timing of counselling and change of PA. PA was retrospectively reported during 12 months before pregnancy and recorded one week monthly during pregnancy.

RESULTS

Individualized counselling by a physiotherapist resulted in small changes of recreational PA (2.7 MET hours/week, p=0.056) up to gestational week 25 compared with the similar decreasing tendency of PA in the control group. The women decreased recreational PA after week 30. Sample size of 550 women at high risk for GDM per group would be needed for a PA study.

CONCLUSIONS

The optimal time window for increasing PA must be earlier than in the last trimester of pregnancy. Sample size for a study to increase PA by 2.7 MET hours/week on pregnant women at high risk of GDM should be about 550 per group.

Physical activity and pregnancy: past and present evidence and future recommendations

PURPOSE

In this review, we provide researchers and practitioners with an overview of the physical activity and pregnancy literature to promote prenatal physical activity, improve measurement, further elucidate the role of activity in reducing maternal health complications, and inform future research.

METHOD

We examined past and present physical activity and pregnancy studies and highlight key papers with a focus on maternal health outcomes to best inform physical activity promotion efforts.

RESULTS

We discuss: (a) historical overview of prenatal physical activity relative to the physical activity guidelines, how they have changed over time, and how evidence of the effect of prenatal activity on maternal/fetal health outcomes has affected clinical recommendations; (b) existing tools and challenges associated with measuring prenatal physical activity; (c) empirical evidence on multilevel determinants of prenatal activity to guide future intervention work; (d) empirical evidence of prenatal activity on adverse maternal outcomes (gestational diabetes mellitus, preeclampsia, excessive gestational weight gain) from observational and intervention studies; and (e) summary/recommendations for future research and practice.

CONCLUSIONS

The physical activity and pregnancy literature has evolved over the past 50 years, and there is sufficient empirical evidence to support the promotion of moderate-to-vigorous prenatal physical activity for maternal health benefits. Future studies and interventions should be carefully designed, theoretically driven, and include validated and reliable activity measures. Researchers and practitioners should also consider the multifaceted determinants and outcomes of prenatal physical activity and intervene to promote physical activity before, during, and after pregnancy.

Review of self-reported physical activity assessments for pregnancy: summary of the evidence for validity and reliability

BACKGROUND

Epidemiological studies and surveillance systems of pregnant women often rely on collection of physical activity through self-report. This systematic review identified and summarised self-reported physical activity assessments with evidence for validity and reliability among pregnant women.

METHODS

Peer-reviewed articles published through 2011 were included if they assessed validity and/or reliability of an interviewer- or self-administered physical activity questionnaire or diary among pregnant women.

RESULTS

We identified 15 studies, including 12 studies that assessed questionnaires and 4 studies that assessed diaries, conducted in Australia, Finland, Norway, the U.K., the U.S. and Vietnam. For questionnaires, 92% (11/12) assessed mode, all assessed frequency and/or duration and 58% (7/12) collected information on perceived intensity. All but one study (92%) assessed validity of the questionnaires. Questionnaires compared with objective measures (accelerometers, pedometers) ranged from slight to fair agreement, while comparison with other self-reported measures ranged from substantial to almost perfect agreement. Five studies (42%) assessed test-retest reliability of the questionnaires, ranging from substantial to almost perfect agreement. The four studies on diaries were all assessed for validity against objective measures, ranging from slight to substantial agreement.

CONCLUSIONS

Selection of valid and reliable physical activity measures that collect information on dose (type, frequency, duration, intensity) is recommended to increase precision and accuracy in detecting associations of physical activity with maternal and fetal outcomes.

Accuracy of physical activity assessment during pregnancy: an observational study

Background

Prenatal physical activity may improve maternal and infant health and lower future disease risk for both mother and baby; however, very few physical activity assessment methods have been validated for use during pregnancy. The purpose of this study was to evaluate the accuracy of a subjective physical activity record (PAR) and an objective activity monitor, against a reference standard to quantify moderate and vigorous physical activity (MVPA) in pregnant women. The reference standard was based on participant interviews to determine if a woman was an exerciser and confirmed with information obtained from the PAR and a heart rate monitor.

Methods

Fifty-two pregnant women completed a physical activity record (PAR) and wore a SenseWear^® Mini Armband (SWA) activity monitor over a 7-day period at 18 weeks gestation. Total minutes spent in MVPA were totaled from both modalities and evaluated against the reference standard using contingency analysis and Pearson's chi-square test to evaluate the number of women meeting minimum prenatal physical activity recommendations (at least 3, 30 minute sessions of exercise per week). Both modalities were also tested individually and collectively to assess their ability as indicators of activity using empirically determined cut-offs as indicated by receiver-operator characteristic curves. These experimentally-derived criteria were also tested with Pearson's chi-square test.

Results

According to the reference standard, 13 of 52 participants (25%) met the criterion of 3, 30 minute sessions of volitional, moderate-intensity activity. When compared to the reference standard, both the PAR and SWA overestimated exercise status; 42 (81%) and 52 (100%) participants, respectively, achieved 90 minutes of MVPA (P < 0.0001 for both comparisons). Single-modality predictors of MVPA did not show a significant correlation. A composite predictor of MVPA offered the most favorable option for sensitivity and specificity (true positives, n = 8 and true negatives, n = 36) using cut-offs of 280 and 385 minutes/week for the PAR and SWA, respectively.

Conclusion

Compared to the reference standard, time spent in MVPA obtained from the PAR or SWA overestimated the prevalence of women meeting prenatal exercise recommendations. The most accurate predictor of women meeting current prenatal exercise guidelines was identified by using the PAR and SWA collectively.

Accuracy of physical activity monitors in pregnant women

PURPOSE

To determine the step count accuracy of three pedometers and one accelerometer in pregnant women during treadmill walking.

METHODS

Participants were 30 women in the second or third trimester (20-34 wk) who were screened for pregnancy-related risk factors. Each participant was fitted with a belt containing three physical activity monitors: Yamax Digiwalker SW-200 (DW), New Lifestyles NL 2000 (NL), and GT3X ActiGraph accelerometer (ACT). The Omron HJ-720ITC (HJ) was placed in the pants' front pocket. Participants walked at 54, 67, 80, and 94 m · min for 2 min each. Actual steps were determined by an investigator using a hand-tally counter. The mean percent of steps recorded was calculated for each device at each speed and compared. Pearson correlations were used to determine the effect of body mass index and tilt angle on pedometer accuracy.

RESULTS

There was a significant interaction between speed and device (F9,20 = 7.574, P < 0.001). Across all speeds, the NL and HJ had the lowest error. The ACT and DW underestimated the actual steps taken, particularly at the slower walking speeds. At 54 m · min, the ACT averaged 77.5% of steps and the DW averaged 56.9% of steps. Significant differences in the mean percent of steps recorded were found between devices at all speeds. Body mass index was only significantly correlated with percent of steps recorded by the NL, and there were no significant correlations between steps recorded and tilt angle.

CONCLUSIONS

In pregnant women, the ACT and DW had more error than the NL and HJ. On the basis of these results, the NL and HJ should be considered for use in further research studies and physical activity programs that focus on walking during pregnancy.

Agreement between pedometer and accelerometer in measuring physical activity in overweight and obese pregnant women

BACKGROUND

Inexpensive, reliable objective methods are needed to measure physical activity (PA) in large scale trials. This study compared the number of pedometer step counts with accelerometer data in pregnant women in free-living conditions to assess agreement between these measures.

METHODS

Pregnant women (n = 58) with body mass index ≥25 kg/m(2) at median 13 weeks' gestation wore a GT1M Actigraph accelerometer and a Yamax Digi-Walker CW-701 pedometer for four consecutive days. The Spearman rank correlation coefficients were determined between pedometer step counts and various accelerometer measures of PA. Total agreement between accelerometer and pedometer step counts was evaluated by determining the 95% limits of agreement estimated using a regression-based method. Agreement between the monitors in categorising participants as active or inactive was assessed by determining Kappa.

RESULTS

Pedometer step counts correlated moderately (r = 0.36 to 0.54) with most accelerometer measures of PA. Overall step counts recorded by the pedometer and the accelerometer were not significantly different (medians 5961 vs. 5687 steps/day, p = 0.37). However, the 95% limits of agreement ranged from -2690 to 2656 steps/day for the mean step count value (6026 steps/day) and changed substantially over the range of values. Agreement between the monitors in categorising participants to active and inactive varied from moderate to good depending on the criteria adopted.

CONCLUSIONS

Despite statistically significant correlations and similar median step counts, the overall agreement between pedometer and accelerometer step counts was poor and varied with activity level. Pedometer and accelerometer steps cannot be used interchangeably in overweight and obese pregnant women.

Measuring physical activity during pregnancy

BACKGROUND

Currently, little is known about physical activity patterns in pregnancy with prior estimates predominantly based on subjective assessment measures that are prone to error. Given the increasing obesity rates and the importance of physical activity in pregnancy, we evaluated the relationship and agreement between subjective and objective physical activity assessment tools to inform researchers and clinicians on optimal assessment of physical activity in pregnancy.

METHODS

48 pregnant women between 26-28 weeks gestation were recruited. The Yamax pedometer and Actigraph accelerometer were worn for 5-7 days under free living conditions and thereafter the International Physical Activity Questionnaire (IPAQ) was completed. IPAQ and pedometer estimates of activity were compared to the more robust and accurate accelerometer data.

RESULTS

Of 48 women recruited, 30 women completed the study (mean age: 33.6 ± 4.7 years; mean BMI: 31.2 ± 5.1 kg/m(2)) and 18 were excluded (failure to wear [n = 8] and incomplete data [n = 10]). The accelerometer and pedometer correlated significantly on estimation of daily steps (ρ = 0.69, p < 0.01) and had good absolute agreement with low systematic error (mean difference: 505 ± 1498 steps/day). Accelerometer and IPAQ estimates of total, light and moderate Metabolic Equivalent minutes/day (MET min(-1) day(-1)) were not significantly correlated and there was poor absolute agreement. Relative to the accelerometer, the IPAQ under predicted daily total METs (105.76 ± 259.13 min(-1) day(-1)) and light METs (255.55 ± 128.41 min(-1) day(-1)) and over predicted moderate METs (-112.25 ± 166.41 min(-1) day(-1)).

CONCLUSION

Compared with the accelerometer, the pedometer appears to provide a reliable estimate of physical activity in pregnancy, whereas the subjective IPAQ measure performed less accurately in this setting. Future research measuring activity in pregnancy should optimally encompass objective measures of physical activity.

TRIAL REGISTRATION

Australian New Zealand Clinical Trial Registry Number: ACTRN12608000233325. Registered 7/5/2008.

Antenatal depression: a rationale for studying exercise

BACKGROUND

Major depressive disorder (MDD) in pregnancy or antenatal depression poses unique treatment challenges and has serious consequences for mothers, unborn babies, and families when untreated. This review presents current knowledge on exercise during pregnancy, antidepressant effects of exercise, and the rationale for the specific study of exercise for antenatal depression.

METHOD

A systematic literature review was performed using English language articles published in Medline, PsycINFO, CINAHL, and the Cochrane Library from 1985 to January 2010.

RESULTS

There is a broad literature supporting the antidepressant effects of exercise, but a paucity of studies specifically for antenatal depression. A small number of observational studies have reported that regular physical activities improve self-esteem and reduce symptoms of anxiety and depression during pregnancy. To date, there have not been randomized controlled studies of exercise for the treatment of MDD in pregnant women.

CONCLUSIONS

Systematic studies are needed to assess exercise as a treatment alternative for MDD during pregnancy. In consideration of the benefits of exercise for the mother and baby, and the burden of depression, studies are needed to determine the role of exercise for pregnant women with depression.

Physical activity and preterm birth: a literature review

Preterm birth is a major reason for infant mortality and morbidity, representing a public health concern worldwide. Regular and voluntary physical activity is healthy behaviour that should be incorporated by everyone, including pregnant women. On the other hand, some women are exposed to highly demanding occupational physical activities during pregnancy that might represent a threat to the fetus and to their own health. This paper is a literature review of studies (1987-2007) on physical activity during pregnancy and its relationship to preterm birth. Although the effects measured by the studies are not strong and the evidence is impaired by many methodological flaws, it seems that recreational or leisure-time physical activities performed regularly provide protection against prematurity. Studies on occupational physical activities, especially standing for long periods, present contrasting results - some presenting standing as a risk factor, but most showing no association. Housework and other daily activities do not seem to be associated with preterm birth. Regardless of the methodological aspects of the studies reviewed, there is a chance that the real effect of occupational physical activity is being blurred by some underlying factors not easily measured in epidemiological investigations. Our conclusions do not reject the idea that working conditions might represent danger for the pregnancy outcome, but only raise the question that maybe the mechanisms through which employment-related physical activities have been considered up till now could be better and more thoroughly studied. Future studies should pay additional attention to psychological and socioeconomic characteristics, without neglecting biological plausibility.

Pre- and postnatal women's leisure time physical activity patterns: a multilevel longitudinal analysis

The purpose of this study was to examine women's leisure time physical activity (LTPA) before pregnancy, during pregnancy, and through the first 7 months postnatal. Pre- and postnatal women (n = 309) completed the 12-month Modifiable Activity Questionnaire and demographic information. Multilevel modeling was used to estimate a growth curve representing the average change in LTPA over time and intraindividual variations in the average growth curve over time. Growth curve estimates for the linear quadratic, and cubic trends were significant (p < .05), indicating that LTPA declined during pregnancy but then increased following birth. The results also demonstrated that the individual trajectories of LTPA varied substantially from the average growth curve. One demographic predictor variable (having other children at home) was significant (p < .05).

Activity patterns and time allocation during pregnancy: A longitudinal study of British women

OBJECTIVE

Few studies provide data regarding the integrated everyday activities of Western pregnant women. The study aimed to quantify changes in the daily activity of women during pregnancy and to examine whether pregnancy has a differential impact on different activity domains.

DESIGN

A prospective, longitudinal study of maternal time allocation and activity was carried out.

METHODS

The time allocation patterns of 57 healthy nulliparous pregnant women were assessed at 16, 25, 34 and 38 weeks gestation by semi-structured interview. Mean total daily activity levels (DALs) were estimated according to the intensity and duration of each activity reported. Self-reported activity was sub-divided into occupational, recreational, domestic and nocturnal activity ratios.

RESULTS

From 16 to 34 weeks gestation mean self-reported DAL declined significantly from 1.54 to 1.40 METS (Metabolic Equivalent TEE Score, where TEE is total energy expenditure) (p < 0.001). In the different activity domains, mean occupational activity ratio decreased (p < 0.002) whilst nocturnal activity ratio increased (p < 0.002) from 16 to 34 weeks. Mean recreational activity ratio decreased significantly between 25 and 38 weeks (p < 0.001) but no significant changes were observed in mean domestic activity ratio.

CONCLUSIONS

Low-risk pregnancy has a differential impact on occupational, recreational and domestic domains. Economies in energy expenditure appear to be made in occupational and recreational activity while domestic activities are largely maintained during pregnancy. Changes in physical activity may be influenced more by the type of activity rather than the intensity of activity.

Validation of self-reported recreational exercise in pregnant women in the Norwegian Mother and Child Cohort Study

We compared the self-reported frequency of recreational exercise and corresponding metabolic equivalent (MET)-minutes with physical activity measured with a position and motion sensor in pregnant women. One hundred and twelve women in the Norwegian Mother and Child Cohort Study (MoBa) completed questions about weekly participation in recreational exercise by week 17 of pregnancy and participated in the validation study around week 20. Data from a validated motion sensor (ActiReg) that measures physical activity and total energy expenditure (TEE) served as the "gold standard." Self-reported recreational exercise was compared with the following ActiReg-based measures: physical activity energy expenditure (PAEE), minutes of vigorous physical activity (VPA), physical activity level (PAL) and TEE. Pearson's correlations between self-reported weekly exercise and the objectively assessed variables were: rPAEE=0.26, rVPA=0.32, rPAL=0.30 (all P<0.01) and rTEE=0.17 (P=0.07). The partial correlation coefficients between the questionnaire responses and the ActiReg measurements were similar after adjusting for parity, body mass index, education, age, height and smoking, but rTEE increased (r=0.27, P<0.01). We observed significant positive associations between self-reported exercise activities and motion sensor measurements of physical activity, indicating that the questions used for exercise assessment in MoBa may be useful for ranking pregnant women according to the recreational exercise level.

A comparison of direct versus self-report measures for assessing physical activity in adults: a systematic review

BACKGROUND

Accurate assessment is required to assess current and changing physical activity levels, and to evaluate the effectiveness of interventions designed to increase activity levels. This study systematically reviewed the literature to determine the extent of agreement between subjectively (self-report e.g. questionnaire, diary) and objectively (directly measured; e.g. accelerometry, doubly labeled water) assessed physical activity in adults.

METHODS

Eight electronic databases were searched to identify observational and experimental studies of adult populations. Searching identified 4,463 potential articles. Initial screening found that 293 examined the relationship between self-reported and directly measured physical activity and met the eligibility criteria. Data abstraction was completed for 187 articles, which described comparable data and/or comparisons, while 76 articles lacked comparable data or comparisons, and a further 30 did not meet the review's eligibility requirements. A risk of bias assessment was conducted for all articles from which data was abstracted.

RESULTS

Correlations between self-report and direct measures were generally low-to-moderate and ranged from -0.71 to 0.96. No clear pattern emerged for the mean differences between self-report and direct measures of physical activity. Trends differed by measure of physical activity employed, level of physical activity measured, and the gender of participants. Results of the risk of bias assessment indicated that 38% of the studies had lower quality scores.

CONCLUSION

The findings suggest that the measurement method may have a significant impact on the observed levels of physical activity. Self-report measures of physical activity were both higher and lower than directly measured levels of physical activity, which poses a problem for both reliance on self-report measures and for attempts to correct for self-report - direct measure differences. This review reveals the need for valid, accurate and reliable measures of physical activity in evaluating current and changing physical activity levels, physical activity interventions, and the relationships between physical activity and health outcomes.

Avaliação da reprodutibilidade e validade de questionário de atividade física para gestantes

INTRODUÇÃO: A prática de atividade física tem sido incentivada por vários organismos nacionais e internacionais visando a promoção de saúde. Entretanto não existe consenso acerca da influência e da intensidade ótima de atividade física durante a gestação, possivelmente devido a dificuldades de mensuração e classificação do nível de atividade física através de questionários. Não se identificou qualquer estudo de validação de questionário de atividade física em gestantes no Brasil. O objetivo do presente estudo é analisar a reprodutibilidade e validade concorrente de um questionário de atividades físicas para gestantes. MÉTODOS: Em amostra de 68 gestantes, no segundo trimestre de gestação foi realizada entrevista para aplicação do questionário, que foi repetida com aproximadamente uma semana de intervalo e no puerpério. No período entre as duas primeiras entrevistas, as mulheres utilizaram monitor de freqüência cardíaca (n=38). RESULTADOS: As análises de reprodutibilidade foram adequadas com coeficientes de correlação intraclasse variando de 0,54 a 0,85. A análise das variáveis categóricas, com questões subjetivas e de autopercepção da atividade física, resultou em maior intervalo de coeficiente kappa com valores entre 0,29 e 0,76 entre a aplicação do questionário com uma semana de intervalo, e 0,08 a 0,70 comparado ao puerpério. As análises de validade conduziram a resultado satisfatório quanto à média das diferenças encontrada por intermédio do gráfico de Bland e Altman (1986) entre o questionário e o freqüencímetro. Entretanto, o intervalo da dispersão não se apresentou adequado, visto que variou em mais de sete horas para atividades leves e em quase onze horas por dia para atividades moderadas. As análises do presente estudo parecem assegurar a reprodutibilidade do questionário de atividade física para gestantes. No entanto, com relação à validação, a comparação com os resultados obtidos pelo freqüêncímetro não mostrou graus de concordância adequados.

Walking for health in pregnancy: assessment by indirect calorimetry and accelerometry

The purpose of this study was to examine RT3 accelerometer activity counts and activity energy expenditure of 36 pregnant women at 20 and 32 weeks' gestation during treadmill walking and free-living conditions. During treadmill walking, oxygen consumption was collected, and activity energy expenditure was estimated for a 30-min walk at a self-selected walking pace. The number of min it would take a pregnant woman to meet exercise recommendations (i.e., kcal/week) were calculated. Preliminary activity count cut points at a self-selected walking pace were then estimated and applied in interpreting free-living data. For the treadmill walking condition, the self-selected walking pace significantly decreased from 20 to 32 weeks' gestation. Additionally, few women (< 12% each day) met physical activity guidelines in the free-living condition. Encouraging pregnant women to walk for 30-40 min per day at a self-selected walking pace may be an appropriate public health recommendation.

Activity levels in pregnant New Zealand women: relationship with socioeconomic factors, well-being, anthropometric measures, and birth outcome

Activity during pregnancy has health implications for mother and child. The aim of this prospective cohort study was to examine changes in activity levels during pregnancy; the influence of socioeconomic factors and well-being on activity, and the influence of activity on maternal anthropometric measures and birth outcome. Twenty-four hour activity diaries were collected for 3 d in months 4 and 7 of pregnancy in 197 volunteers. Anthropometric measures and questionnaires to determine personal details were collected at these times and 2 months post-partum. Health records were used to supply infant measures. The time spent on each activity category was calculated, and used to calculate overall daily metabolic equivalents (METs). Low socioeconomic (SES) group 24 h activity levels were significantly higher than for high SES or welfare groups (p = 0.013). Activity declined throughout pregnancy in all groups (p = 0.002). Women with children had higher 24 h activity, spending 41% more time walking and (or) on housework than nulliparous women (p = 0.013). Reduced well-being was associated with lower levels of activity. Sleep and lying down time influenced 2 month post-partum body mass (upper quartile gained 2.54 kg, lower quartile lost 0.24 kg, p < 0.001). Mean infant gestational age increased with increasing 24 h activity (p = 0.047). No infants were born prematurely to mothers who spent more than 190 min/d walking or doing housework activities in month 4. Probability of infant admission to the neonatal intensive care unit (NICU) declined with time spent walking or doing housework in month 4 (p = 0.007). Mean (SE) birth weight was 3883 (+/-165) g in the 10% of women spending less than 530 min sleeping or lying down per day, compared with 3413 (+/-104) g in the 10% of women spending 725 min or more sleeping or lying down. Socioeconomic factors were therefore important influences on activity levels during pregnancy. Inactivity, especially in early pregnancy, was associated with more maternal weight retention at 2 months post-partum and a greater probability of admission to NICU and premature delivery.

Dietary intake, weight gain, and birth outcomes of physically active pregnant women: a pilot study

Pregnant women have increased energy and nutrient needs. Exercise also increases energy and glucose demands. This pilot study examined whether women who were physically active during pregnancy met their dietary needs, gained weight adequately, avoided hypoglycemia, and had normal birth outcomes. Based on a convenience sample, 11 active women were studied from 18 weeks gestation to delivery. They exercised for 40 min at 70% VO2 peak, 3-4 times per week. Weekly measures included capillary blood glucose concentrations, body mass, and food records. Birth outcome measures included baby mass, length, and activity, pulse, grimace, appearance, and respiration (APGAR) scores. Our findings suggest that these subjects had lower average energy intake (8680 +/- 490 kJ/d) than recommended for the 2nd and 3rd trimesters (13,020 +/-185 kJ/d; 13,480 +/- 185 kJ/d, respectively, p < 0.0001). Protein requirements for pregnancy were exceeded. Average intakes of iron (19 +/- 2 mg/d) and folate (356 +/- 33 microg/d) were lower than Recommended Dietary Allowances (RDAs) (27 mg/d and 600 microg/d, respectively) and milk products consumed were less than the recommended daily servings. Four women gained less weight per week than recommended for pregnancy. No hypoglycemia occurred post-exercise. Birth outcome measures were within normal ranges. Comparative studies with a larger number of subjects are required to determine if active pregnant women have adequate nutrient intakes and weight gain.

Physical activity and fetal growth during pregnancy

OBJECTIVE

To assess the separate and combined relationships of aerobic physical activity during pregnancy, maternal weight gain during pregnancy, and height to the fetal growth ratio.

METHODS

The aerobic physical activity of 51 healthy, nonsmoking pregnant women was assessed for 48 hours at both 20 and 32 weeks of pregnancy by accelerometry, heart rate monitoring, and physical activity recall. We analyzed the relationship between maternal physical activity and the fetal growth ratio.

RESULTS

All women included in the analysis completed healthy, uncomplicated pregnancies and delivered infants with a weight range of 2,743-4,943 g. Aerobic physical activity assessed by accelerometry was strongly and inversely associated with fetal growth ratio (r=-0.42; P<.002). Infants born to women in the highest quartile of physical activity weighed 608 g less than infants born to women in the lowest quartile. The inverse relationship between physical activity and fetal growth ratio was moderated by maternal height; virtually all the effect was seen in mothers taller than the sample median (1.65 m). Similar relationships were found across methods of physical activity measurement.

CONCLUSION

Aerobic physical activity in pregnancy may be an important determinant of birth weight within the normal range, especially in taller mothers.

LEVEL OF EVIDENCE

II.

Significant changes in physical activity among pregnant women in the UK as assessed by accelerometry and self-reported activity

OBJECTIVE

Research on the impact of maternal physical activity on pregnancy outcomes has often employed subjective measures of physical activity obtained by diary or questionnaire. This study investigates the feasibility of using accelerometry as an objective measure of physical activity of pregnant women compared with subjective data obtained via activity recall among pregnant women.

DESIGN

Activity data were collected prospectively on 57 women at 12, 16, 25, 34 and 38 weeks of gestation. Total daily physical activity was assessed by ambulatory accelerometer and activity interview (self-report). Maternal personality variables (health value, extroversion) were assessed by established scales.

SETTING

Leicestershire, UK.

SUBJECTS

Pregnant women were recruited by voluntary participation via antenatal booking clinics. In all, 64 pregnant women with low-risk pregnancy were enrolled onto the study, of whom 57 completed the study.

RESULTS

Mean 24 h physical activity levels (PAL) decreased significantly from second to third trimester as assessed by self-report interview (1.51-1.29 Metabolic Equivalent TEE-h/day, P<0.01) and accelerometry (200.05-147.42 counts/min, P<0.01). The correlation between the two measures declined as pregnancy progressed (r value ranging from 0.55 to 0.08). Compliance with the accelerometers declined from 90% at 12 weeks to 47% at 34 weeks (P<0.01). Compliance with the self-report interviews was 100%. Those who fully complied with the accelerometry demonstrated a significantly higher health value (P<0.05) and a significantly greater level of extroversion (P<0.05) than those who did not.

CONCLUSIONS

Accelerometers and self-reported activity interviews both indicated a significant decline in PAL during pregnancy. Although subjects showed a willingness to use both methods, accelerometers resulted in variable compliance with 72 h monitoring. Both techniques may be limited by the need to measure low levels of physical activity during the third trimester.

SPONSORSHIP

Cambridge Neurotechnology Ltd, UK, assisted with the provision of Actiwatch accelerometers.

A Review of Physical Activity Patterns in Pregnant Women and Their Relationship to Psychological Health

Regular physical activity contributes positively to physical and psychological health. Adverse consequences of inactivity may be an especially important problem among pregnant women. Up to 60% are inactive during pregnancy. This review found consistent evidence that physical activity is reduced during pregnancy; however, few investigators have sought to quantify physical activity patterns among pregnant women using well validated measures. Some of the barriers to physical activity during pregnancy, such as depression, anxiety and fatigue, have been shown to be attenuated by regular exercise performed by non-pregnant samples. There is a need to better understand the relationships between these factors and physical activity during pregnancy. Available retrospective and prospective results suggest that both leisure time and work-related physical activities are decreased across pregnancy. Intensity and duration decrease both during pregnancy compared with pre-pregnancy and in the third trimester compared with the first. There is a need for well designed longitudinal investigations that document pregnancy-related changes in physical activity at frequent intervals during pregnancy using validated and more precise measures of physical activity. Reductions in physical activity and a worsening mood are common during pregnancy. If the relationship between physical inactivity and mood disturbances is indeed observed and maintained during pregnancy, then decreases in physical activity in the third trimester would be expected to result in a worsening mood. In recent years, increased attention has been paid to antenatal mood disturbances, and this research has yielded a host of important findings. Prior correlational and experimental research with non-pregnant samples has demonstrated a consistent relationship between physical inactivity and mood disturbances. Whether this relationship occurs among pregnant women and/or is maintained as women progress during pregnancy is uncertain. Prior investigations have revealed that there is higher rate of mood disturbance during pregnancy than following pregnancy but little is known about the mechanisms that cause these mood disturbances. It is important to better understand changes in mood with pregnancy because mood disturbances can have major negative consequences for a pregnant woman. The major adverse consequences of depression among pregnant women are largely the same as those of non-pregnant individuals. Only six investigations have quantified the relationship between changes in physical activity and changes in mood during pregnancy. The available evidence suggests that inactivity is associated with worse mood. Additional research into this topic is warranted due to the limited number of published papers and the design and methodology limitations of these investigations.

Physical activity and mood during pregnancy

PURPOSE

To compare three physical activity (PA) measures in pregnant women and examine mood correlates of physical activity changes during pregnancy.

METHODS

A sample of 12 pregnant women (PW) was recruited during their first trimester and 12 nonpregnant women (NPW) (baseline age = 30.7 +/- 4.4 yr) were matched to the PW (29.8 +/- 4.2 yr). Once monthly, for seven consecutive months, total weekly energy expenditure (TWEE) was assessed using a physical activity diary (PAD) and a recall interview (PAR). Accelerometers were worn for 3 d each month. Mood was also assessed. A two-factor mixed-model ANOVA was used to analyze the data (2 groups [PW vs NPW] x 7 times across pregnancy).

RESULTS

Mean PAR TWEE and daily mean MTI counts were positively and moderately correlated with mean PAD TWEE (PW: r = 0.40 and NPW: r = 0.50, P < 0.001). The MTI counts decreased significantly in PW by 23% from gestational weeks 12 to 36 compared with a 5% decrease in NPW. Fatigue and vigor scores improved from gestational weeks 12 to 16 and worsened from weeks 32 to 36 in PW. Changes in PA were not correlated to changes in mood in either group.

CONCLUSIONS

The results provide some evidence for the validity of the 7-d PAR and accelerometer as measures of physical activity in pregnancy. Healthy women who maintain an above average level of physical activity during the second and third trimesters can enjoy mood stability.