Maternal Physical Activity Research Articles

Mode of Delivery according to Leisure Time Physical Activity before and during Pregnancy: A Multicenter Cohort Study of Low-Risk Women.

Objectives. To examine the association between maternal leisure time physical activity and mode of delivery. Study Design. Population-based multicentre cohort. From the Danish Dystocia Study, we included 2,435 nulliparous women, who delivered a singleton infant in cephalic presentation at term after spontaneous onset of labor in 2004-2005. We analysed mode of delivery according to self-reported physical activity at four stages, that is, the year before pregnancy and during first, second, and third trimester, in logistic regression models. Further, we combined physical activity measures at all four stages in one variable for a proportional odds model for cumulative logits. Main Outcome Measures. Mode of delivery (emergency caesarean section; vacuum extractor; spontaneous vaginal delivery). Results. The odds of emergency caesarean section decreased with increasing levels of physical activity with statistically significant trends at all four time stages except the third trimester. This tendency was confirmed in the proportional odds model showing 28% higher odds of a more complicated mode of delivery among women with a low activity level compared to moderately active women. Conclusions. We found increasing leisure time physical activity before and during pregnancy associated with a less complicated delivery among low-risk, nulliparous women.

Effect of Maternal Diet Diversity and Physical Activity on Neonatal Birth Weight: A Study from Urban Slums of Mumbai

Effect of Maternal Diet Diversity and Physical Activity on Neonatal Birth Weight: A Study from Urban Slums of Mumbai

Objectively-measured physical activity in children is influenced by social indicators rather than biological lifecourse factors: Evidence from a Brazilian cohort.

The aim of this study was to examine the longitudinal influences of early life social and biological indicators on objectively measured physical activity. All newborns in 2004 in the city of Pelotas, Southern Brazil were enrolled in a birth cohort study. At the age of 6 years, a follow-up visit included objective assessment of overall physical activity (summarized in milli-g, 1 mg = 0.001 g) by tri-axial wrist worn accelerometry. The associations between early life exposures, such as type of delivery, parity, birth weight, preterm delivery, maternal physical activity, socioeconomic position, and overall physical activity were examined. Valid accelerometry data were obtained from 2604 children (78.2% of the eligible individuals). Girls were less active than boys (β = − 8.65 mg; 95% CI − 10.0; − 7.30). Higher socioeconomic position was related to lower activity levels (β = − 9.69 mg. 95% CI − 12.45; − 6.93) and a similar association was found with maternal schooling. No associations were found with birthweight, type of delivery or preterm delivery. This study provides evidence for the role of some social factors in explaining children's physical activity behaviors, and minimizes the influence of some early life biological factors at determining physical activity levels.

151: Do maternal body composition and physical activity influence birthweight percentiles in twins?

151: Do maternal body composition and physical activity influence birthweight percentiles in twins?

Influence of maternal physical activity on infant's body composition.

Physical activity (PA) during pregnancy might contribute to reduce neonatal adiposity, a predictor of metabolic disturbances. The objective of the study was to evaluate the association between maternal PA intensity and neonatal body composition. Maternal PA measured by accelerometry and nutrition were documented during pregnancy, as well as neonatal body composition by dual-energy X-ray absorptiometry following delivery. Associations between PA at 17 and 36 weeks (time spent in moderate PA (MPA), vigorous PA (VPA) status and their interaction) and neonatal body composition were addressed by multivariate regression analyses. From 104 women, 50 (48%) and 16 (18%) performed VPA at 17 and 36 weeks of pregnancy. Performing VPA at either time was associated with a decreased birthweight (BW), while only VPA at 17 weeks decreased neonatal adiposity (fat percentage: -2.3 ± 0.8%, p = 0.003). MPA at 36 weeks was associated with an increased lean mass (2.0 ± 0.8 g per min day-1 , p = 0.012). Significant interactions were found for BW and bone mineral content (BMC). MPA at 17 weeks tended to increase BW, but not BMC, in the no VPA strata. By contrast, high levels of MPA (≥112 min d-1 ) combined with VPA at 17 weeks reduced neonatal BMC and BW compared with no VPA (BMC: -5.4 ± 2.0 g, p = 0.008, BW: -302.8 ± 83.7 g, p = 0.0003). Differences were not significant with low MPA levels. Exercise intensity modulates neonatal body composition. The long-term significance of a reduced BW, adiposity and BMC with VPA requires further study.

Quality Predictors of Abdominal Fetal Electrocardiography Recording in Antenatal Ambulatory and Bedside Settings

Background: Fetal electrocardiography using an abdominal monitor (Monica AN24™) could increase the diagnostic use of fetal heart rate (fHR) variability measurements. However, signal quality may depend on factors such as maternal physical activity, posture, and bedside versus ambulatory setting. Methods: Sixty-three healthy women wore the monitor at home and 42 women during a hospital stay. All women underwent a posture experiment, and all home and 13 hospital participants wore the monitor during daytime and nighttime. The success rate (SR) of fHR detection was analyzed in relation to maternal physical activity, posture, daytime versus nighttime, and other maternal and fetal predictors. Results: Ambulatorily, the SR was 86.8% for nighttime and 40.2% for daytime. The low daytime SR was largely due to effects of maternal physical activity and posture. The in-hospital SR was lower during nighttime (71.1%) and similar during daytime (43.3%). SR was related to gestational age, but not affected by pre-pregnancy and current body mass index or fetal growth restriction. Conclusions: The success of beat-to-beat fHR detection strongly depends on the home/hospital setting and predictors such as time of recording, activity levels, and maternal posture. Its clinical utility may be limited in periods of unsupervised recording with physical activity or posture shifts.

An overview of maternal and fetal short and long-term impact of physical activity during pregnancy.

To explore information available in the literature about the possible benefits resulting from physical activity (PA) in non-risky pregnant women, repercussion on maternal organism, fetal development, and on long-term offspring health. Critical narrative review using online databases. Through critical discussion of studies focused on PA practiced during pregnancy, it was observed that some of the outcomes investigated on both mother and offspring showed conflicting findings. Considering the impact of maternal PA in certain offspring characteristics, due to the fact that their findings come from studies with small samples, they do not allow the stablishment of scientific evidence. However, a feature that shows broad consensus among studies is the view of PA during pregnancy as a safe intervention for mother and fetus. In situations where studies employing PA of moderate-intensity have not enough power to ensure a positive influence on certain clinical outcomes, what is observed is the lack of their influence, not negative impacts. Regarding epigenetic modulations measured late in the offspring, it has been attributed to PA a positive modulatory role on metabolic, hemodynamic and even on behavioral characteristics. However, possible mechanisms involved in these epigenetic changes have not been sufficiently explored. Maternal PA appears to be safe for both mother and fetus, and additional studies are needed to confirm the real influence of this practice in the offspring, as well as the perpetuation and transfer of these features between generations.

Role of maternal occupational physical activity and psychosocial stressors on adverse birth outcomes

ObjectivesWe examined the association of an array of estimated maternal occupational physical activities and psychosocial stressors during pregnancy with odds for preterm birth (PTB) and small-for-gestational age (SGA).MethodsData for infants...

Maternal physical and sedentary activities in relation to reproductive outcomes following IVF

Physical activity could benefit reproductive function through its ability to regulate energy balance and improve insulin sensitivity, but its association with IVF outcomes remains unclear. The aim of this study was to evaluate whether pre-treatment physical and sedentary activity is associated with outcomes of IVF. The Environment and Reproductive Health Study is an ongoing prospective cohort study that enrols subfertile couples at Massachusetts General Hospital Fertility Center. Time spent in physical and sedentary activities in the year before IVF treatment is self-reported using a validated questionnaire. This analysis included 273 women who underwent 427 IVF cycles. Women engaged in a median of 2.8 h per week of moderate-to-vigorous activities. Time spent in moderate-to-vigorous physical activities and total metabolic equivalent task hours before IVF were not associated with probability of implantation, clinical pregnancy or live birth. Of the specific physical activities, only greater time spent in aerobics, rowing, and on the ski or stair machine was associated with higher probability of live birth. Time spent in total and specific sedentary activities were not associated with clinical outcomes of IVF. Physical activity is unlikely to have a deleterious effect on IVF success and certain forms of vigorous activity may be beneficial.

A follow-up study to assess the determinants and consequences of physical activity in pregnant women of Cuenca, Spain.

BackgroundIn recent years, the influence of physical exercise on pregnancy outcomes has been widely debated. Despite the numerous studies addressing the relationship between maternal physical activity and pregnancy outcomes, the evidence for consistent and significant impact of regular exercise during pregnancy on fetal growth remains lacking. The aims of this study were, first, to assess the level of physical activity performed throughout the pregnancy by objective (accelerometer) and self-reported (questionnaire) measurements, and, second, to ascertain pre-pregnancy physical activity levels, to estimate the relationship between levels of physical activity and some pregnancy and neonatal outcomes.Methods/designThis was a prospective cohort study. Participants were pregnant women (n = 194) aged 18 to 40 years who attended for three quarterly appointments for pregnancy ultrasound scans at the Virgen de la Luz Hospital in Cuenca, Spain. All participants provided written informed consents to participate in the study. Physical activity during the pregnancy follow-up was assessed by a self-reported Pregnancy Physical Activity Questionnaire and sleep log; also objectively by a GT3X accelerometer (ActiGraph). Furthermore, pregnancy symptoms inventory, nutritional behavioural assessment, socio-demographic characteristics, and anthropometry and body composition were measured.At the end of the follow up, the following main outcomes were determined: pregnancy outcomes (incidence of gestational diabetes mellitus, pre-eclampsia, pregnancy-induced hypertension, weight gain during pregnancy, type of delivery, and neonatal outcomes (gestational age, birth weight, gender, Apgar score 1 min/5 min, type of resuscitation (I/II/III/IV), and pH of umbilical cord blood). Descriptive statistics for cross-sectional data, linear mixed regression models for absolute differences in changes baseline-final measurements were used as statistical analyses.DiscussionAlthough the effectiveness of physical activity programmes on improving maternal and neonatal outcomes has heretofore been studied, the impact of free time physical activity during pregnancy has not been assessed using objective measures. This paper reports the design of a prospective cohort study that aims to assess the physical activity levels of pregnant women, and to estimate the relationship between those physical activity levels with maternal and neonatal outcomes.This study could contribute to providing evidence for the formulation of recommendations for physical activity for pregnant women.

Maternal Physical Activity, Placental Variation In LEKR1/CCNL1, And Offspring Birthweight - A Sex-specific Gene-Environment Interaction

Gene-environment interactions have been reported to contribute to fetal growth. The placenta mediates effects of maternal behaviors on fetal growth. The role of placental genetic variation in previously reported sex-specific associations of maternal leisure time physical activity (LTPA) with offspring birth size is unknown. PURPOSE: We examined whether offspring sex-specific associations of maternal LTPA with offspring birthweight (BW) differ by placental fetal growth-related common genetic variations. METHODS: Participants (N=412) were identified from the Omega study, a prospective pregnancy cohort study. Participants reported LTPA duration (hours/week) and energy expenditure (MET-hours/week) in the year before pregnancy (ppLTPA) and in early pregnancy (epLTPA). BW was abstracted from medical records. Placental tissue was collected at delivery and genotyped for common single nucleotide polymorphisms (minor allele frequency (MAF) >20%) related to fetal growth: rs1482853 (LEKR1/CCNL1), rs9883204 (ADCY5), rs1042725 (HMGA2), rs724557 (LCORL), rs1801253 (ADRB1), and rs4432842 (5q11.2). Interaction terms and stratified regression models were used to determine effect modification of associations of maternal LTPA with offspring BW by genotypes. RESULTS: Among females, rs1482853 (MAF=43%) modified associations of ppLTPA (P for interaction=0.05) and epLTPA (P for interaction=0.01) duration with BW. Each quartile increase in ppLTPA duration was associated with 154g greater BW (95% CI: 12, 295) among females homozygous for the rs1482853 minor allele, while it was associated with 120g lower BW (95% CI: -223, -18) among heterozygous females. Similarly, each quartile increase in epLTPA duration was associated with 158g greater BW (95% CI: 1, 316) among females homozygous for the rs1482853 minor allele, while it was associated with a marginally significant 53g lower BW (95% CI: -156, 50) among heterozygous females. Genotypes did not modify LTPA-BW associations among males. Results were similar for energy expenditure. CONCLUSIONS: Placental genetic variation in LEKR1/CCNL1 may modify associations between maternal LTPA and birthweight among females, but not males. Replication of results and research on mechanisms of interaction between LTPA, placental genes, and fetal growth are warranted.

Maternal Physical Activity During Pregnancy

PURPOSE: Maternal physical activity during pregnancy influences infant’s birth weight and body composition, but its association with bone health has been poorly evaluated. This study aims at documenting in a longitudinal study the effect of objectively measured physical activity during pregnancy on infant’s bone mineral content (BMC) and density (BMD). METHODS: 7-day accelerometry recordings (Actigraph GT3X+) were performed in low-risk pregnant women at 17 and 36 weeks of gestation. BMC and BMD were evaluated by DXA in mothers and infants within 2 weeks after birth. Sociodemographics, maternal lifestyle habits, pre-pregnancy physical activity, medical history and pregnancy outcomes were collected through interview and charts’ review. Mean counts per minute (CPM) and daily time spent at moderate and vigorous physical activity (MVPA) were calculated for each period from accelerometry data. The association between physical activity data and infant’s BMC and BMD was evaluated through multiple regression models, adjusting for infant sex and length, parity, maternal pre-pregnancy BMI, gestational weight gain, multivitamin use, gestational age at delivery, infant’s age at DXA, maternal BMD and pre-pregnancy physical activity. RESULTS: : For this preliminary analysis, DXA assessment and accelerometry data for at least one visit were available for 108 pregnant women (age=29.7 ± 3.7 y; pre-pregnancy BMI=23.6 ± 4.7 kg/m2; 59.3% nulliparous) and their baby (birth weight=3451 ± 424 g; gestational age=39.7 ± 1.2 weeks; 45.4% boys). Daily time spent at MVPA at 17 weeks was negatively associated with infant’s BMC and BMD (β= -0.45 g and -0.0009 g/cm3 per 10 min of MVPA, p=0.033 and 0.026), after adjustment for confounders. Similarly, mean CPM at 17 weeks was significantly associated with infant’s BMC and BMD (β= -1.92 g and -0.004 g/cm3 per 100 CPM, p=0.010 and p=0.004). Mean CPM at 36 weeks was also associated with child’s BMC (β= -0.004 g/cm3 per 100 CPM, p=0.024). CONCLUSIONS: Higher levels of maternal physical activity measured by accelerometry during pregnancy were associated with a decrease in infant’s BMC and BMD. The impact of maternal nutrition on this association remains to be investigated. Supported by the Fondation des Étoiles, Canadian Institutes of Health Research and Fonds de Recherche du Québec-Santé.

Physical Activity Levels in Chinese One-Year-Old Children and Their Parents, an Early STOPP China Study.

BackgroundPhysical activity (PA) is associated with health benefits, already in childhood. However, little is known about actual levels, patterns and gender differences in PA level in very young children. This study examines Chinese one-year-old children and their parents’ PA levels and patterns, and assesses the correlations between children’s PA level and gender, body mass index standard deviation score (BMI SDS), parental BMI and parental PA level.MethodsData from 123 families participating in the Early STOPP China study were used. Families were recruited based on parental BMI and were classified as either high-risk or low-risk of obesity. Parents and children wore an ActiGraph GT3X+ to assess the average PA levels. PA levels and hourly patterns during weekdays and weekends were examined as were correlations with gender, BMI SDS, parental BMI and parental PA levels.ResultsThere were no significant differences in children’s averaged PA between risk groups, genders, or between weekdays and weekends. Children’s peak average activity level was at 7 pm and they were least active at 3 pm (p<0.001). Both mothers and fathers demonstrated a similar PA pattern as their children, although paternal PA level was consistently lower than that of mothers and children. No significant association was found between children’s PA and their gender, BMI SDS, parental BMI or paternal PA levels. Maternal PA was found positively associated with child PA (p<0.05).ConclusionPA in one-year-old Chinese children vary over the day but weekdays and weekends are similar. At this age, children’s PA is not related to gender, BMI SDS, parental BMI or paternal PA. Larger scale studies with more contextual information are needed to improve the understanding of our findings.

Physical Activity Level, Modeling, and Importance to Mothers of Preschool Children

Physical activity (PA) is an important component of obesity prevention for children and adults. This study compared maternal and child PA levels, maternal modeling of PA, and importance mothers place on PA for herself and her child to maternal and child BMI categories. Survey participants (n=550) were 72% white and 37% had a college degree or higher. Categorizing mothers by weight status indicated that 26%, 23%, 21%, and 30%, were underweight/low normal weight (BMI&lt;22.5), high normal weight (BMI≥22.5 to &lt;25), overweight (BMI ≥25 to &lt;30), or obese (BMI≥30), respectively. Mean maternal PA levels were low (15.44±9.98SD; 0–42 point scale), with obese mothers (n=165) scoring significantly lower than underweight/low normal weight mothers (14.20±9.91SD vs 17.17±10.47SD, p=0.018). Using a 5‐point 2‐item scale, mothers indicated they felt modeling PA behaviors to their children was important and modeled PA 3.08±1.22SD days a week in the past month. Compared to both categories of normal weight mothers, obese mothers placed significantly less importance on modeling PA behaviors (3.91±0.89SD vs 4.24±0.84SD and 4.32±0.69SD, p&lt;0.001) to their children and spent significantly fewer days a week in the last month modeling PA behaviors (2.80±1.23SD vs 3.35±1.14SD and 3.21±1.25SD, p&lt;0.001). Mothers placed less importance on PA for themselves than for their children (mean 3.49±0.97SD vs 3.83±0.87SD, on a 5‐point scale). Obese mothers placed significantly less importance on PA for themselves than mothers in all other weight categories. PA level of participants’ children was moderate (26.19±11.42SD, 0–42 point scale). No significant differences were found among child BMI categories and child PA levels. The importance mothers placed on modeling PA and importance placed on PA for their children did not differ among child BMI weight categories. Mothers of overweight children reported modeling PA behaviors significantly more days per week than mothers with middle normal weight (25th to 74th percentile) children (3.41±1.27SD vs 2.85±1.17SD). The importance mothers placed on their own PA was lower among mothers of underweight children and tended to increase as child BMI increased. Findings suggest that mothers of obese children may be more sensitive to the importance of modeling PA and its importance to health. Encouragement of all parents to promote PA and model PA behaviors to children is important for obesity prevention.Support or Funding InformationUSDA NIFA #2011‐68001‐30170

Maternal exercise during pregnancy promotes physical activity in adult offspring.

Previous rodent studies have shown that maternal voluntary exercise during pregnancy leads to metabolic changes in adult offspring. We set out to test whether maternal voluntary exercise during pregnancy also induces persistent changes in voluntary physical activity in the offspring. Adult C57BL/6J female mice were randomly assigned to be caged with an unlocked (U) or locked (L) running wheel before and during pregnancy. Maternal running behavior was monitored during pregnancy, and body weight, body composition, food intake, energy expenditure, total cage activity, and running wheel activity were measured in the offspring at various ages. U offspring were slightly heavier at birth, but no group differences in body weight or composition were observed at later ages (when mice were caged without access to running wheels). Consistent with our hypothesis, U offspring were more physically active as adults. This effect was observed earlier in female offspring (at sexual maturation). Remarkably, at 300 d of age, U females achieved greater fat loss in response to a 3-wk voluntary exercise program. Our findings show for the first time that maternal physical activity during pregnancy affects the offspring's lifelong propensity for physical activity and may have important implications for combating the worldwide epidemic of physical inactivity and obesity.-Eclarinal, J. D., Zhu, S., Baker, M. S., Piyarathna, D. B., Coarfa, C., Fiorotto, M. L., Waterland, R. A. Maternal exercise during pregnancy promotes physical activity in adult offspring.

Maternal Leisure-time Physical Activity and Risk of Preterm Birth: A Systematic Review of the Literature.

Preterm birth is a leading cause of infant death and the role of maternal physical activity on this risk remains unclear. This systematic review examined low, moderate and vigorous leisure-time physical activity (LTPA) during pregnancy and the outcome of preterm birth. Key words related to preterm birth and physical activity were used to search relevant databases (Medline, Cochrane, CINAHL, Sports Discuss and Scopus). Studies were excluded if they did not measure physical activity as an exposure in pregnant women, did not provide information on gestational age at delivery, and were not published in English. All study designs and sample sizes were considered. The search generated 1472 studies. There were 27 studies included in this review of which 23 received high quality reporting scores. Eleven studies reported a lower risk of preterm birth for women who performed LTPA during pregnancy, while 14 studies reported null findings. Only 2 studies detected a significantly higher risk of preterm birth with LTPA during pregnancy. This review of literature up to 2014 provides additional evidence to support the assertion that healthy pregnant women can engage in low, moderate, and even some vigorous levels of LTPA without risk for preterm birth.

Association of heart rate and blood pressure among European adolescents with usual food consumption: The HELENA study

Background and aimIn adults, there is some evidence that improving diet reduces blood pressure (BP) and the subsequent risk of cardiovascular diseases (CVDs). However, studies that analyse this association in adolescents are still scarce. The objective of the present study was to examine the associations between heart rate, systolic (SBP), diastolic (DBP) and mean arterial blood pressure (MAP) among European adolescents and usual intake of vegetables, fruits, dairy products, meat, fish, high-sugar foods and savoury snacks. Methods and resultsIn total, 2283 adolescents from the HELENA-study (12.5–17.5 years old; 1253 girls) were included. Dietary intake was assessed using two computerized 24-hour dietary recalls. Age, sex, body mass index, maternal educational level, physical activity and Tanner stage were considered as confounders. Associations were examined by mixed model analysis stratified by sex. Tests for trend were assessed by tertiles of intake while controlling for the aforementioned confounders. Dairy products and fish intake were negatively associated with BP and heart rate. Significant decreasing trends were observed for heart rate and BP across tertiles of dairy products, fish intake and high-sugar foods intake (p < 0.05). Significant increasing trends were observed for SBP and MAP across tertiles of savoury snack intake (p < 0.05). ConclusionSignificant but small inverse associations between fish and dairy products consumption with blood pressure and heart rate have been found in European adolescents. Dietary intervention studies are needed to explore these associations in the context of the modification of several risk factors for the prevention of cardiovascular diseases.

Preconception and pregnancy: opportunities to intervene to improve women's diets and lifestyles.

Recently, large-scale trials of behavioural interventions have failed to show improvements in pregnancy outcomes. They have, however, shown that lifestyle support improves maternal diet and physical activity during pregnancy, and can reduce weight gain. This suggests that pregnancy, and possibly the whole periconceptional period, represents a 'teachable moment' for changes in diet and lifestyle, an idea that was made much of in the recent report of the Chief Medical Officer for England. The greatest challenge with all trials of diet and lifestyle interventions is to engage people and to sustain this engagement. With this in mind, we propose a design of intervention that aims simultaneously to engage women through motivational conversations and to offer access to a digital platform that provides structured support for diet and lifestyle change. This intervention design therefore makes best use of learning from the trials described above and from recent advances in digital intervention design.

Maternal dietary intake and physical activity habits during the postpartum period: associations with clinician advice in a sample of Australian first time mothers.

BackgroundNumerous health benefits are associated with achieving optimal diet and physical activity behaviours during and after pregnancy. Understanding predictors of these behaviours is an important public health consideration, yet little is known regarding associations between clinician advice and diet and physical activity behaviours in postpartum women. The aims of this study were to compare the frequency of dietary and physical activity advice provided by clinicians during and after pregnancy and assess if this advice is associated with postpartum diet and physical activity behaviours.MethodsFirst time mothers (n = 448) enrolled in the Melbourne InFANT Extend trial completed the Cancer Council of Australia’s Food Frequency Questionnaire when they were three to four months postpartum, which assessed usual fruit and vegetable intake (serves/day). Total physical activity time, time spent walking and time in both moderate and vigorous activity for the previous week (min/week) were assessed using the Active Australia Survey. Advice received during and following pregnancy were assessed by separate survey items, which asked whether a healthcare practitioner had discussed eating a healthy diet and being physically active. Linear and logistic regression assessed associations of advice with dietary intake and physical activity.ResultsIn total, 8.6 % of women met guidelines for combined fruit and vegetable intake. Overall, mean total physical activity time was 350.9 ± 281.1 min/week. Time spent walking (251.97 ± 196.78 min/week), was greater than time spent in moderate (36.68 ± 88.58 min/week) or vigorous activity (61.74 ± 109.96 min/week) and 63.2 % of women were meeting physical activity recommendations. The majority of women reported they received advice regarding healthy eating (87.1 %) and physical activity (82.8 %) during pregnancy. Fewer women reported receiving healthy eating (47.5 %) and physical activity (51.9 %) advice by three months postpartum. There was no significant association found between provision of dietary and/or physical activity advice, and mother’s dietary intakes or physical activity levels.ConclusionsHealthy diet and physical activity advice was received less after pregnancy than during pregnancy yet no association between receipt of advice and behaviour was observed. More intensive approaches than provision of advice may be required to promote healthy diet and physical activity behaviours in new mothers.Trial registrationAustralian New Zealand Clinical Trials Registry (ACTRN12611000386932 13/04/2011)

Maternal Leisure Time Physical Activity and Infant Birth Size

Associations of maternal leisure time physical activity with birth size are inconsistent. Roles of infant sex and maternal prepregnancy body mass index (BMI) in these associations have not been studied. Participants (N = 3,310) in the Omega study, a cohort in Washington State (1996-2008), reported leisure time physical activity duration and energy expenditure in the year prepregnancy and in early pregnancy (mean 15 weeks gestation). Regression models estimated mean differences in infant head circumference, birthweight, and ponderal index (birthweight/length) across quartiles of pre- or early-pregnancy leisure time physical activity. We assessed effect modification by infant sex or prepregnancy overweight/obese status (BMI ≥ 25 kg/m). We observed positive associations between prepregnancy leisure time physical activity and head circumference overall and among male infants. Among males, each quartile increase in prepregnancy physical activity duration was associated with 0.14 cm (95% confidence interval = 0.046, 0.24; trend P = 0.004) greater head circumference. We did not observe associations between leisure time physical activity and birthweight or ponderal index overall. Each quartile increase in pre- or early-pregnancy physical activity duration was associated with 17-23 g lower birthweight among female infants and among women with normal prepregnancy BMI. We observed positive associations between prepregnancy leisure time physical activity and head circumference among male infants, and inverse associations of pre- and early-pregnancy physical activity with birthweight among female infants and women with normal prepregnancy BMI. Future studies should confirm results and elucidate mechanisms of observed associations.