Sports and leisure-time physical activity in pregnancy and birth weight: a population-based study

The association of physical activity during pregnancy with birthweight extremes: A scoping review

OBJECTIVES

Birthweight (BW) indicates newborn health and is a risk factor for development of chronic diseases later in life. The aim was to investigate whether or not prenatal physical activity (PA) influences BW extremes and how PA influences BW extremes in those diagnosed with pregnancy-related diseases.

DESIGN

We performed a scoping review.

METHODS

Searches were completed on five databases and studies identified were uploaded to Covidence.

RESULTS

Across the five databases 3114 studies were identified and after screening, 69 of these studies were used for the final review. Of the 61 studies that considered low BW (LBW)/small for gestational age (SGA) infants, the majority of results (69 %) indicated that PA during pregnancy had no significant impact on LBW or SGA infants. In addition, 11 % of studies reported a significant decrease in the prevalence of LBW infants, however two studies (3 %) reported a significant increase in LBW or SGA infants, likely relating to individuals with high body mass index and poor adherence to PA. Of the 41 studies that did report LGA/macrosomia, 34 % reported that PA significantly reduced the prevalence of higher BW infants. One study reported the association between meeting exercise recommendations and reducing the odds of LGA infants in those with pregnancy-related diseases.

CONCLUSIONS

We provide evidence on the association of prenatal PA with BW extremes. It is suggested that prenatal PA does not increase the risk of delivering LBW/SGA infants and may reduce the prevalence of large BW infants. Further research is needed to confirm these relationships and explain their underlying mechanisms.

Systematic Reviews on the Prevention of Adverse Pregnancy Outcomes Related to Maternal Obesity to Improve Evidence-Based Counselling

Background

Health professionals and their patients should understand the importance of evidence. In the case of gestational diabetes mellitus, which is often associated with an abnormally high body mass index, the immediate and long-term outcome of women and their offspring depends in part on advice and implementation of lifestyle changes before, during and after pregnancy.

Methods

Up to September 2023, MEDLINE, CENTRAL, and WEB OF SCIENCE were used to identify systematic reviews and meta-analyses on the prevention of gestational diabetes. The ROBIS and AMSTAR criteria were analyzed for all systematic reviews.

Results

A total of 36 systematic reviews were identified. Dietary interventions, physical activity or a combined approach all reduced adverse pregnancy outcomes such as gestational diabetes, pregnancy-induced hypertension and related morbidities. Within the randomized controlled trials included in the 36 systematic reviews, the type, intensity and frequency of interventions varied widely. The primary outcomes, reporting and methodological quality of the 36 systematic reviews and meta-analyses also varied.The meta-analysis with the highest ROBIS and AMSTAR-2 scores was selected to design an icon array based on a fact box simulating 100 patients.

Conclusions

We propose a methodology for selecting the best evidence and transforming it into a format that illustrates the benefits and harms in a way that can be understood by lay patients, even if they cannot read. This model can be applied to counselling for expectant mothers in low and high-income countries, regardless of socioeconomic status, provided that women have access to appropriately trained healthcare providers.

Associations of dietary and sedentary behaviours of pregnant women with their children's birth weight: findings from the CHAT trial in Australia

OBJECTIVE

To examine the associations of pregnant women's dietary and sedentary behaviours with their children's birth weight.

DESIGN

Secondary data analysis was conducted using data from a randomised controlled trial, Communicating Healthy Beginnings Advice by Telephone, conducted in Australia. Information on mothers' socio-demographics, dietary and sedentary behaviours during pregnancy was collected by telephone survey at the third trimester. Birth weight data were extracted from the child's health record book. Multinomial logistic regression models were built to examine the associations of pregnant women's dietary and sedentary behaviours with children's birth weight.

SETTING

Participating families.

PARTICIPANTS

Pregnant women and their children.

RESULTS

A total of 1132 mother-child dyads were included in the analysis. The majority of infants (87 %, n 989) were of normal birth weight (2500 g to <4000 g), 4 % (n 50) had low birth weight (<2500 g) and 8 % (n 93) had macrosomia (≥4000 g). Mothers who ate processed meat during pregnancy were more likely to have macrosomia (adjusted risk ratio (ARR) 1·80, 95 % CI (1·12, 2·89)). The risk of macrosomia decreased as the number of dietary recommendations met by mothers increased (ARR 0·84, 95 % CI (0·71, 0·99)). Children's birth weight was not associated with mothers' sedentary time. Children's low birth weight was not associated with mothers' dietary and sedentary behaviours during pregnancy.

CONCLUSION

Maternal consumption of processed meat during pregnancy was associated with an increased risk of macrosomia. Increasing number of dietary recommendations met by mothers was associated with a lower risk of macrosomia. The findings suggested encouraging pregnancy women to meet dietary recommendation will benefit children's birth weight.

Impact of Physical Activity of Pregnant Women on Obstetric Outcomes

Regular and well-planned physical activity (PA) has a positive impact on pregnancy outcomes. In this study, we determine the impact of the PA of pregnant women on the occurrence of certain pregnancy outcomes, such as type of labor, duration of pregnancy, and birthweight. The study is based on the results of a Polish national survey performed between 2011 and 2017 on a group of 9170 women. The Pregnancy Physical Activity Questionnaire (PPAQ) was used to estimate the PA of pregnant women. Light intensity PA accounts for the largest proportion of women's total energy expenditure. Increase in women's total energy expenditure was associated with an increase in the birthweight of a child. A similar relationship was observed in the case of light and moderate PA. Vaginal birth was more common among women with higher total energy expenditure. Mothers of preterm children showed lower energy expenditure for each type of PA compared to term pregnancies. There was also a correlation between moderate and vigorous PA and low birthweight. Our study indicates that PA undertaken by pregnant women has a positive impact on pregnancy outcomes.

Leisure-time physical activity in Amazonian pregnant women and offspring birth weight: A prospective cohort study

Compelling evidence supports the current international recommendation of at least 150 min/week of leisure-time physical activity (LTPA) during pregnancy. However, the potential relationship between LTPA and birth weight (BW) remains unclear in low- and middle-income countries. The purpose of this study was to examine the association between LTPA during pregnancy and offspring BW in an Amazonian population. Prospective cohort study was carried-out with 500 pregnant women and their offspring followed-up in the MINA-Brazil study, which was conducted in Cruzeiro do Sul, Western Brazilian Amazon. LTPA was assessed in the second (mean 19.6, SD 2.4 weeks) and third (mean 27.8, SD 1.6 weeks) gestational trimesters by a standardised interview and categorised according to the recommended cut-off of at least 150 min/week. We calculated offspring BW z-scores by sex and gestational age. We then explored the effect of LTPA during pregnancy on offspring BW, the association between LTPA and small-for-gestational-age (SGA) or large-for-gestational-age (LGA) births, and the mediating role of excessive and insufficient gestational weight gain (GWG). At least 150 min/week of LTPA during the third gestational trimester was associated with an offspring BW decrease of -0.35 z-score (95% CI: -0.65, -0.05) or -147.9 grams (95% CI: -260.9, -14.8), without increasing the frequency of SGA foetuses either in the second or third gestational trimester (p > 0.05). Excessive GWG mediated the effect of LTPA on the offspring BW (indirect effect = -0.05 z-score [95% CI: -0.10, -0.00] or -34.7 grams (95% CI: -66.1, -3.3]). This mediation effect was not observed for insufficient GWG. LTPA in the third, but not in the second, trimester of pregnancy was inversely associated with offspring BW without increasing the frequency of SGA, an effect that was partly mediated by excessive GWG.

Relationships between Objectively Measured Sedentary Behavior during Pregnancy and Infant Birthweight

Background: Although numerous studies have assessed physical activity during pregnancy and relationships with infant outcomes, such as birthweight, few have evaluated sedentary behavior. Our objective was to evaluate sedentary behavior across pregnancy and relationships with infant birthweight in a sociodemographically diverse sample. Methods: We measured device-assessed sedentary behavior and physical activity over three days at 16–18, 24–26, and 32–34 weeks gestation and infant birthweight from medical records among 71 participants. We used linear regression to assess relationships between sedentary behavior at each evaluation period with birthweight-for-gestational age Z-scores (BW-for-GA). Results: There were no linear relationships between sedentary behavior and BW-for-GA at any evaluation period. We observed a modest curvilinear relationship between sedentary behavior at 16–18 weeks and BW-for-GA (R² = 0.073, p = 0.021). Low and high levels of sedentary behavior predicted lower BW-for-GA. Multivariate models suggested that this relationship was independent of physical activity levels. Conclusions: Considering the high levels of sedentary behavior during pregnancy observed in many studies, even modest associations with birthweight merit further consideration. Relationships might not be evident later in pregnancy or if only linear relationships are considered. More detailed studies could help guide recommendations on sedentary behavior during pregnancy and the development of more comprehensive interventions.

Effects of Maternal Exercise During Pregnancy on Perinatal Growth and Childhood Obesity Outcomes: A Meta-analysis and Meta-regression

BACKGROUND

Perinatal growth abnormalities program susceptibility to childhood obesity, which is further exaggerated by maternal overweight and obesity (MO) during pregnancy. Exercise is highly accessible, but reports about the benefits of maternal exercise on fetal growth and childhood obesity outcomes are inconsistent, reducing the incentives for pregnant women to participate in exercise to improve children's perinatal growth.

OBJECTIVE

This systematic review and meta-analysis aims to establish evidence-based efficacy of exercise in mothers with normal weight (MNW) and MO during pregnancy in reducing the risks of perinatal growth abnormalities and childhood obesity. In addition, the impacts of exercise volume are also assessed.

METHODS

The PubMed, ScienceDirect, Web of Science, and Cochrane Library databases were searched from inception to February 15, 2020. We included randomized controlled trials with exercise-only intervention or exercise with other confounders in pregnant MNW (body mass index, BMI 18.5-24.9 kg/m²) and MO (BMI ≥ 25 kg/m²), which were further subgrouped in the meta-analysis. Primary outcomes included birth weight, preterm birth, small for gestational age (SGA), large for gestational age (LGA), infant and childhood weight, and childhood obesity. A linear meta-regression analysis was also used to explore the effects of exercise volume on outcomes.

RESULTS

99 studies were included in the meta-analysis (n = 596,876), and individual study quality ranged from fair to good according to the Newcastle-Ottawa scale assessment. Exercise only interventions in MNW reduced preterm birth by 15% (26 studies, n = 76,132; odds ratio [OR] 0.85; 95% CI 0.72, 1.01; I² = 83.3%), SGA by 17% (33 studies, n = 92,351; OR 0.83; 95% CI 0.71, 0.98; I² = 74.5%) and LGA by 17% (29 studies, n = 84,310; OR 0.83; 95% CI 0.74, 0.95; I² = 60.4%). Exercise only interventions in MO reduced preterm birth by 33% (2 studies, n = 3,050; OR 0.67; 95% CI 0.70, 0.96; I² = 0%), SGA by 27% (8 studies, n = 3,909; OR 0.73; 95% CI 0.50, 1.05; I² = 40.4%) and LGA by 55% (9 studies, n = 81,581; OR 0.45; 95% CI 0.18, 1.11; I² = 98.3%). Exercise only interventions in MNW reduced childhood obesity by 53% (3 studies, n = 6,920; OR 0.47; 95% CI 0.36, 0.63; I² = 77.0%). However, no significant effect was observed in outcomes from exercise confounders in either MNW or MO. In the meta-regression, the volume of exercise-only intervention in MNW was negatively associated with birth weight, greatly driven by volumes more than 810 metabolic equivalents (MET)-min per week. Other outcomes were not associated with exercise volume.

CONCLUSIONS

This systematic review and meta-analysis suggests that exercise during pregnancy in both MNW and MO safely and effectively reduce the risks of preterm birth, SGA, and LGA. Furthermore, MNW exercise also reduces the risk of childhood obesity. Overall, regardless of prepregnancy BMI, maternal exercise during pregnancy provides an excellent opportunity to mitigate the high prevalence of adverse birth outcomes and childhood obesity.

Association between maternal lifestyle factors and low birth weight in preterm and term births: a case-control study

Background

It has been reported that lifestyle factors may affect birth weight; however, few studies have explored the association between lifestyle factors and low birth weight in preterm and term births in China. The objective of this study was to explore the effect of lifestyle on low birth weight in preterm and term births.

Methods

This case-control study was conducted in fourteen hospitals in Jiangmen, Guangdong Province. Data were collected from August 2015 to May 2016 using a standard questionnaire. Data were analysed using logistic regression.

Results

Women who delivered preterm and were physically active (1–3 times per week and ≥ 4 times per week) had reduced odds of having low birth weight babies (aOR = 0.584, 95%CI = 0.394–0.867 and, aOR = 0.516, 95%CI = 0.355–0.752, respectively). Pregnant women who had insufficient gestational weight gain had increased odds of having low birth weight babies (aOR = 2.272, 95%CI = 1.626–3.176). Women exposed to passive smoking had an increased risk of delivering low birth weight infants (aOR = 1.404, 95%CI = 1.057–1.864). Insufficient gestational weight gain and excessive gestational weight gain were both significantly associated with low birth weight (aOR = 1.484, 95%CI = 1.103–1.998 and aOR = 0.369, 95%CI = 0.236–0.577, respectively) for term deliveries. In addition, parity, history of low birth weight, antenatal care and gestational hypertension were significantly associated with the likelihood of low birth weight.

Conclusion

Pregnant women without exercise contraindications should remain physically active. Pregnant women should be aware of the negative effects of smoke and be aware of strategies to protect themselves from passive smoke exposure. Hospitals should inform pregnant women of the importance appropriate gestational weight gain. These recommendations should be put into practice to decrease the prevalence of low birth weight infants.

Physical Activity Patterns among 9000 Pregnant Women in Poland: A Cross-Sectional Study

The aim was to analyze the knowledge and experience of women regarding physical activity during their latest pregnancy. An anonymous questionnaire was completed electronically, in 2018, by 9345 women who gave birth at least once, with 52% of the women having performed exercises during pregnancy. Physically non-active respondents suffered from gestational hypertension (9.2% vs. 6.7%; p < 0.01) and gave birth prematurely (9% vs. 7%; p < 0.01) to newborns with a low birth weight significantly more often (6% vs. 3.6%; p < 0.001). Physically active women delivered vaginally more often (61% vs. 55%; p < 0.001) and were more likely to have a spontaneous onset of the delivery as compared with non-active women (73.8% vs. 70.7% p = 0.001). The women who were informed by gynaecologist about the beneficial influence of physical activity during pregnancy exercised significantly more often (67% vs. 44% p < 0.001). In addition, 13% of the women felt discrimination due to their physical activity during a pregnancy, 22% of respondents' physical activity was not accepted by their environment, and 39.1% of the women were told by others to stop physical exercise because it was bad for the baby's health. Physical activity during pregnancy is associated with improved fitness, decreased pregnancy ailments occurrence, and therefore influences the course of pregnancy and delivery in a positive way.

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

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

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

Background

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

Methods

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

Results

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

Conclusions

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

Trial registration

PROSPERO trial registration CRD42018102109.

Electronic supplementary material

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

Associations between maternal physical activity in early and late pregnancy and offspring birth size: remote federated individual level meta-analysis from eight cohort studies

OBJECTIVE

Evidence on the impact of leisure time physical activity (LTPA) in pregnancy on birth size is inconsistent. We aimed to examine the association between LTPA during early and late pregnancy and newborn anthropometric outcomes.

DESIGN

Individual level meta-analysis, which reduces heterogeneity across studies.

SETTING

A consortium of eight population-based studies (seven European and one US) comprising 72 694 participants.

METHODS

Generalised linear models with consistent inclusion of confounders (gestational age, sex, parity, maternal age, education, ethnicity, BMI, smoking, and alcohol intake) were used to test associations between self-reported LTPA at either early (8-18 weeks gestation) or late pregnancy (30+ weeks) and the outcomes. Results were pooled using random effects meta-analyses.

MAIN OUTCOME MEASURES

Birth weight, large-for-gestational age (LGA), macrosomia, small-for-gestational age (SGA), % body fat, and ponderal index at birth.

RESULTS

Late, but not early, gestation maternal moderate to vigorous physical activity (MVPA), vigorous activity, and LTPA energy expenditure were modestly inversely associated with BW, LGA, macrosomia, and ponderal index, without heterogeneity (all: I2  = 0%). For each extra hour/week of MVPA, RR for LGA and macrosomia were 0.97 (95% CI: 0.96, 0.98) and 0.96 (95% CI: 0.94, 0.98), respectively. Associations were only modestly reduced after additional adjustments for maternal BMI and gestational diabetes. No measure of LTPA was associated with risk for SGA.

CONCLUSIONS

Physical activity in late, but not early, pregnancy is consistently associated with modestly lower risk of LGA and macrosomia, but not SGA.

TWEETABLE ABSTRACT

In an individual participant meta-analysis, late pregnancy moderate to vigorous physical activity modestly reduced birth size outcomes.

Exercise in Pregnancy and Children's Cardiometabolic Risk Factors: a Systematic Review and Meta-Analysis

BACKGROUND

Maternal metabolic health during the prenatal period is an established determinant of cardiometabolic disease risk. Many studies have focused on poor offspring outcomes after exposure to poor maternal health, while few have systematically appraised the evidence surrounding the role of maternal exercise in decreasing this risk. The aim of this study is to characterize and quantify the specific impact of prenatal exercise on children's cardiometabolic health markers, at birth and in childhood.

METHODS

A systematic review of Scopus, MEDLINE, EMBASE, CENTRAL, CINAHL, and SPORTDiscus up to December 2017 was conducted. Randomized controlled trials (RCTs) and prospective cohort studies of prenatal aerobic exercise and/or resistance training reporting eligible offspring outcomes were included. Four reviewers independently identified eligible citations and extracted study-level data. The primary outcome was birth weight; secondary outcomes, specified a priori, included large-for-gestational age status, fat and lean mass, dyslipidemia, dysglycemia, and blood pressure. We included 73 of the 9804 citations initially identified. Data from RCTs was pooled using random effects models. Statistical heterogeneity was quantified using the I2 test. Analyses were done between June and December 2017 and the search was updated in December 2017.

RESULTS

Fifteen observational studies (n = 290,951 children) and 39 RCTs (n = 6875 children) were included. Observational studies were highly heterogeneous and had discrepant conclusions, but globally showed no clinically relevant effect of exercise on offspring outcomes. Meta-analyzed RCTs indicated that prenatal exercise did not significantly impact birth weight (mean difference [MD] - 22.1 g, 95% confidence interval [CI] - 51.5 to 7.3 g, n = 6766) or large-for-gestational age status (risk ratio 0.85, 95% CI 0.51 to 1.44, n = 937) compared to no exercise. Sub-group analyses showed that prenatal exercise reduced birth weight according to timing (starting after 20 weeks of gestation, MD - 84.3 g, 95% CI - 142.2, - 26.4 g, n = 1124), type of exercise (aerobic only, MD - 58.7 g, 95% CI - 109.7, - 7.8 g; n = 2058), pre-pregnancy activity status (previously inactive, MD - 34.8 g, 95% CI - 69.0, - 0.5 g; n = 2829), and exercise intensity (light to moderate intensity only, MD - 45.5 g, 95% CI - 82.4, - 8.6 g; n = 2651). Fat mass percentage at birth was not altered by prenatal exercise (0.19%, 95% CI - 0.27, 0.65%; n = 130); however, only two studies reported this outcome. Other outcomes were too scarcely reported to be meta-analyzed.

CONCLUSIONS

Prenatal exercise does not causally impact birth weight, fat mass, or large-for-gestational-age status in a clinically relevant way. Longer follow up of offspring exposed to prenatal exercise is needed along with measures of relevant metabolic variables (e.g., fat and lean mass).

PROTOCOL REGISTRATION

Protocol registration number: CRD42015029163 .

Leisure-Time Physical Activity in Pregnancy and Maternal-Child Health: A Systematic Review and Meta-Analysis of Randomized Controlled Trials and Cohort Studies

BACKGROUND

Evidence suggests that leisure-time physical activity (LTPA) during pregnancy is associated with a reduced risk of preeclampsia, gestational diabetes mellitus (GDM), and preterm birth. However, these results are inconsistent when comparing cohort studies and randomized controlled trials (RCTs).

OBJECTIVE

The purpose of our study was to compare the associations between LTPA in pregnancy and maternal (GDM, preeclampsia, and weight gain during pregnancy) and child health outcomes (preterm birth, birthweight, and fetal growth) between RCTs and cohort studies.

METHODS

We performed a systematic search in PubMed, Web of Science, and EBSCO up to 31 August 2015. Inclusion criteria for experimental studies required randomized trials with a control group and exposure to a physical activity structured program. The inclusion criteria for cohort studies required information on LTPA during pregnancy as an exposure and at least one maternal-child health outcome. We assessed the methodological quality of all studies and performed a meta-analysis to produce summary estimates of the effects using random models.

RESULTS

We included 30 RCTs and 51 cohort studies. The meta-analysis of RCTs indicated that participation in LTPA was associated with lower weight gain during pregnancy, lower likelihood of GDM, and lower likelihood of delivering a large-for-gestational-age infant. Cohort studies indicated that participation in LTPA was associated with lower weight gain during pregnancy, lower likelihood of GDM, and lower risk of preterm delivery.

CONCLUSIONS

Our findings support the promotion of LTPA in pregnancy as a strategy to improve maternal and child health.

Associations of Maternal Light/Moderate Leisure-Time Walking and Yoga With Offspring Birth Size

BACKGROUND

Although perinatal walking and yoga have been associated with decreased risks of pregnancy complications, associations with offspring birth size have been inconsistent. We investigated associations of prepregnancy and early pregnancy leisure-time light/moderate walking and yoga practice with birth size.

METHODS

Study participants (N = 3687) reported leisure-time physical activity duration (hours per week) in the year before pregnancy and early pregnancy. Birth size was abstracted from medical records. Regression was used to determine mean differences in birth weight, head circumference, and ponderal index. Interaction terms were used to assess effect modification by offspring sex.

RESULTS

About one-third of women reported light/moderate leisure-time walking and about 10% reported yoga practice. Women in the highest tertile for prepregnancy (mean: 2.9 h/wk; range: 1.4-20 h/wk) or early pregnancy (mean: 5.9 h/wk; range: 3.1-24 h/wk) light/moderate walking had offspring with 0.9 and 1.5 kg/m³ greater ponderal index (95% confidence interval, 0.3 to 1.4 and 0.7 to 2.4, respectively) compared with women who reported no light/moderate walking in the same time period. Light/moderate walking was not associated with birth weight or head circumference. Yoga practice was not associated with birth size. Associations were similar by offspring sex.

CONCLUSION

Light/moderate leisure-time walking may be associated with greater offspring ponderal index.

Exercise in Pregnancy: First Trimester Risks

Most national guidelines recommend moderate exercise during pregnancy, but this is not followed by the majority of pregnant women. Fear of exercise risks is among reported barriers. In contrast to most reviews focusing on late pregnancy risks, this review evaluates the association between exercise in the first trimester and the risk of miscarriage. A systematic review based on the EMBASE and PUBMED databases was conducted and 5 studies assessing the association between early pregnancy exercise and miscarriage were identified. Diverging findings were reported making no clear conclusion possible. New studies with participants included in the prepregnancy period are needed.

Influence of pre-pregnancy leisure time physical activity on gestational and postpartum weight gain and birth weight - a cohort study

In order to examine the association between pre-pregnancy leisure time physical activities and gestational weight gain, postpartum weight gain and birth weight, we analysed prospectively collected data from 1827 women with singleton term pregnancies. Women were categorised in groups of sedentary women, light exercisers, moderate exercisers and competitive athletes. The results showed that sedentary women on average gained 14.1 kg during pregnancy, whereas light exercisers gained 13.7 kg, moderate exercisers gained 14.3 kg and competitive athletes 16.1 kg. Competitive athletes had an increased risk of having a gestational weight gain above Institute of Medicine (IOM) recommendations with an odds ratio of 2.60 (1.32-5.15) compared to light exercisers. However, birth weight and one year postpartum weight was similar for all four groups. Thus, although competitive athletes gain more weight than recommended during pregnancy, this may not affect birth weight or postpartum weight. Impact statement What is already known on this subjectPrevious studies have found that increased pre-pregnancy physical activity is associated with lower gestational weight gain during the last trimester, but showed no association between the pre-pregnancy level of physical activity and mean birth weight. What the results of this study addWe found that women classified as competitive exercisers had a 2.6-fold increased risk of gaining more weight than recommended compared to light exercisers. Nearly 6 out of 10 women among the competitive exercisers gained more weight than recommended by IOM. Surprisingly, this did not appear to increase birth weight or post-partum weight gain, but other adverse effects cannot be excluded. What the implications are of these findings for clinical practice and/or further researchIn the clinical practice it may be relevant to focus on and advise pre-pregnancy competitive exercisers in order to prevent excessive gestational weight gain.

Sedentary behaviours during pregnancy: a systematic review

Background

In the general population, at least 50% of time awake is spent in sedentary behaviours. Sedentary behaviours are activities that expend less energy than 1.5 metabolic equivalents, such as sitting. The amount of time spent in sedentary behaviours is a risk factor for diseases such as type 2 diabetes, cardiovascular disease, and death from all causes. Even individuals meeting physical activity guidelines are at a higher risk of premature death and adverse metabolic outcomes if they sit for extended intervals. The associations between sedentary behaviour with type 2 diabetes and with impaired glucose tolerance are stronger for women than for men. It is not known whether sedentary behaviour in pregnancy influences pregnancy outcomes, but if those negative outcomes observed in general adult population also occur in pregnancy, this could have implications for adverse outcomes for mothers and offspring.

We aimed to determine the proportion of time spent in sedentary behaviours among pregnant women, and the association of sedentary behaviour with pregnancy outcomes in mothers and offspring.

Methods

Two researchers independently performed the literature search using 5 different electronic bibliographic databases. Studies were included if sedentary behaviours were assessed during pregnancy. Two reviewers independently assessed the articles for quality and bias, and extracted the relevant information.

Results

We identified 26 studies meeting the inclusion criteria. Pregnant women spent more than 50% of their time in sedentary behaviours. Increased time in sedentary behaviour was significantly associated with higher levels of C Reactive Protein and LDL Cholesterol, and a larger newborn abdominal circumference. Sedentary behaviours were significantly higher among women who delivered macrosomic infants. Discrepancies were found in associations of sedentary behaviour with gestational weight gain, hypertensive disorders, and birth weight. No consistent associations were found between sedentary behaviour and other variables such as gestational diabetes. There was considerable variability in study design and methods of assessing sedentary behaviour.

Conclusions

Our review highlights the significant time spent in sedentary behaviour during pregnancy, and that sedentary behaviour may impact on pregnancy outcomes for both mother and child. The considerable heterogeneity in the literature suggests future studies should use robust methodology for quantifying sedentary behaviour.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-017-0485-z) contains supplementary material, which is available to authorized users.

The Influence of Prenatal Exercise on Offspring Health: A Review

Research has continued to demonstrate that exercise during pregnancy is safe. Growing evidence supports that exercise during pregnancy is beneficial for mother and fetus during gestation, with benefits persisting for the child into adulthood. Regardless of income or socioeconomic status, exercise during pregnancy is associated with increased incidence of full-term delivery. Additionally, normalization of birth measures, such as birth weight, occurs when women perform regular exercise throughout gestation. Measures of growth and development further indicate that exercise during pregnancy does not harm and may stimulate healthy growth throughout childhood. Measures of cognition and intelligence demonstrate that exercise during pregnancy causes no harm and may be beneficial. Overall, the benefits of exercise during pregnancy decrease the risk of chronic disease for both mother and child.

Physical Activity Volumes during Pregnancy: A Systematic Review and Meta-Analysis of Observational Studies Assessing the Association with Infant's Birth Weight

Objective This study aims to examine the association between different maternal physical activity exposures during pregnancy and infant's birth weight, body composition, and risk of inadequate weight. Methods Two reviewers (M.B. and J.L.G.) identified observational studies reporting total or leisure time activity during pregnancy and birth weight outcomes. Pooled analyses were performed to summarize the risk associated with high or moderate volumes of physical activity on birth weight. Results A total of 54 studies among 4,080 reported the association between physical activity and birth weight (37 studies) or risks of small or large birth weight. The association between physical activity and birth weight was evaluated by physical activity levels (low, moderate, or high). Despite heterogeneity, pooled results (23 studies) suggested that moderate levels of activity are associated with an increased birth weight (mean difference: 61.5 g, 95% confidence interval [CI]: 16.6, 106.5, 15 studies), while high levels were associated with lower birth weight (mean difference: -69.9 g, 95% CI: -114.8, -25.0, 15 studies). Data were insufficient to provide robust estimates for other outcomes. Conclusions The results of observational studies suggest an inverted u-shaped association between physical activity and birth weight, despite methodological variability. These results could help refining physical activity guidelines for pregnancy and provide guidance for future research.

Do Physical Activity Patterns Across the Lifecourse Impact Birth Outcomes?

The significant impact of physical activity during, or immediately prior to pregnancy on a range of pregnancy and birth outcomes has been established. However, lifecourse theory posits that the antecedents of poor outcomes occur across a larger trajectory of time. The objective of this study was to examine whether physical activity patterns over the lifecourse impact birth outcomes. The sample (n = 1,713) was derived from Waves I, III, and IV of the National Longitudinal Study of Adolescent Health and limited to women who had their first, singleton live birth between Waves III and IV; respondents who had missing data were excluded. Outcome variables included preterm birth (<37 weeks) and low birth weight (<5.5 pounds). Physical activity was categorized as follows: long-term physically active (active at Waves I and III); short-term physically active (active at only Wave I or III); and not physically active (not active at Waves I and III). Survey-weighted logistic regression controlled for socio-demographic and established predictors of poor birth outcomes. Women categorized as long-term physically active had lower rates of preterm births (12.2 vs. 18.7 %) and low birth weight (9.1 vs. 11.1 %) compared to women categorized as not physically active. However, when controlling for covariates, adjusted analysis revealed that physical activity consistency only predicted preterm birth (aOR = 0.55, 95 % CI = 0.33-0.91). Findings suggest that physical activity patterns across the lifecourse may decrease risk of preterm birth. Implications include efforts supporting patterns of physical activity over longer periods of time prior to pregnancy.

Windows of opportunity for physical activity in the prevention of obesity

Tackling increasing rates of obesity is likely to be a defining feature of health care over the next several decades. Adult obesity is a persistent and treatment-resistant problem. Consequently, an emerging theme in the literature is to commence prevention efforts earlier in the developmental time course. This view is based primarily on epidemiological data demonstrating a link between traits manifesting early during development and increased obesity risk in adulthood. Physical activity is a perennial factor in discussions of obesity prevention. However, the optimal timing and type of physical activity interventions to commence remains unclear. Critical developmental windows of plasticity may afford time-limited opportunities to shape body composition across the life course; however, physical activity has not been explicitly considered in these discussions. Although animal models suggest that physical activity commenced earlier in development has differential effects on obesity onset compared to physical activity commenced in adulthood, human research is lacking. In this conceptual review, we consider physical activity during critical developmental periods as a way to mitigate obesity risk later in life.

Associations between prenatal physical activity, birth weight, and DNA methylation at genomically imprinted domains in a multiethnic newborn cohort

Birth weight is a commonly used indicator of the fetal environment and a predictor of future health outcomes. While the etiology of birth weight extremes is likely multifactorial, epidemiologic data suggest that prenatal physical activity (PA) may play an important role. The mechanisms underlying this association remain unresolved, although epigenetics has been proposed. This study aimed to estimate associations between prenatal PA, birth weight, and newborn DNA methylation levels at differentially methylated regions (DMRs) regulating 4 imprinted genes known to be important in fetal development. Study participants (N = 1281) were enrolled as part of the Newborn Epigenetics Study. Prenatal PA was ascertained using the Pregnancy Physical Activity Questionnaire, and birth weight data obtained from hospital records. Among 484 term mother-infant pairs, imprinted gene methylation levels were measured at DMRs using bisulfite pyrosequencing. Generalized linear and logistic regression models were used to estimate associations. After adjusting for preterm birth and race/ethnicity, we found that infants born to mothers in the highest quartile of total non-sedentary time had lower birth weight compared to infants of mothers in the lowest quartile (β = -81.16, SE = 42.02, P = 0.05). These associations appeared strongest among male infants (β = -125.40, SE = 58.10, P = 0.03). Methylation at the PLAGL1 DMR was related to total non-sedentary time (P < 0.05). Our findings confirm that prenatal PA is associated with reduced birth weight, and is the first study to support a role for imprinted gene plasticity in these associations. Larger studies are required.

Changes in leisure time physical activity during pregnancy compared to the prior year

To quantify changes in leisure time physical activity (LTPA) type, frequency, duration and intensity during the first half of pregnancy as compared with the year prior to pregnancy. A cross sectional study was conducted at the Maternal University Hospital in Granada, Spain. A total of 1,175 healthy pregnant women attending a scheduled visit during the 20-22nd gestational week were enrolled in the study. Information about socio-demographic, obstetric and life-style variables during the previous year and the first half of pregnancy were collected. LTPA was quantified by assigning metabolic equivalents to each activity according to frequency, intensity and duration. The prevalence of women who met the optimal physical activity recommendations before and during pregnancy was calculated, and the McNemar-Bowker symmetry test was used to assess changes in type, frequency, intensity and duration of activities between the two periods. Some sort of LTPA was performed before and during pregnancy by 68.6% of the pregnant women. Respectively, just 27.5% and 19.4% of women fulfilled LTPA recommendations prior to pregnancy and during pregnancy; 12.6% of the women meeting recommendations prior to pregnancy later did not meet those recommendations during gestation, and 4.5% showed the reverse trend. A light increase in walking as a LTPA, and a decrease in the rest of the LTPA type activities, were seen during pregnancy. Some 13.4% of women changed from moderate--the year before- to light LTPA- during pregnancy. Pregnancy involved a decrease in LTPA, not only regarding frequency, but also duration and intensity.

Weight loss before conception: A systematic literature review

The prevalence of overweight and obesity in women has increased during the last decades. This is a serious concern since a high BMI before conception is an independent risk factor for many adverse outcomes of pregnancy. Therefore, dietary counseling, intended to stimulate weight loss in overweight and obese women prior to conception has recently been recommended. However, dieting with the purpose to lose weight may involve health risks for mother and offspring. We conducted a systematic literature review to identify papers investigating the effects of weight loss due to dietary interventions before conception. The objective of this study is to assess the effect of weight loss prior to conception in overweight or obese women on a number of health-related outcomes in mother and offspring using studies published between January 2000 and December 2011. Our first literature search produced 486 citations and, based on predefined eligibility criteria, 58 were selected and ordered in full text. Two group members read each paper. Fifteen studies were selected for quality assessment and two of them were considered appropriate for inclusion in evidence tables. A complementary search identified 168 citations with four papers being ordered in full text. The two selected studies provided data for overweight and obese women. One showed a positive effect of weight loss before pregnancy on the risk of gestational diabetes and one demonstrated a reduced risk for large-for-gestational-age infants in women with a BMI above 25 who lost weight before pregnancy. No study investigated the effect of weight loss due to a dietary intervention before conception. There is a lack of studies on overweight and obese women investigating the effect of dietary-induced weight loss prior to conception on health-related variables in mother and offspring. Such studies are probably lacking since they are difficult to conduct. Therefore, alternative strategies to control the body weight of girls and women of reproductive age are needed.

Prepregnancy physical activity in relation to offspring birth weight: a prospective population-based study in Norway-The HUNT Study

Background. The objective was to examine the association between prepregnancy physical exercise and offspring birth weight and to assess the combined association of pre-pregnancy body mass index (BMI) and physical exercise on birth weight. Methods. The study included 2,026 women aged 20–39 years participating in the Norwegian HUNT study and linked with the Medical Birth Registry. We calculated mean differences in birth weight and odds ratios (ORs) for a macrosomic infant (i.e., birth weight >4000 g) using linear and logistic regression analysis. Results. There was no clear association between leisure time physical exercise and mean birth weight. Women who reported no exercise had reduced risk of a macrosomic infant (OR, 0.6; 95% confidence interval (CI), 0.4–0.9) compared to women with a high exercise level. Overweight (BMI ≥ 25.0 kg/m²) was associated with an OR of 1.9 (95% CI, 1.2–2.9) for a macrosomic infant among women who reported low exercise levels, whereas the OR was 1.2 (95% CI, 0.8–1.8) among women with higher exercise levels. Conclusion. There was some evidence that women who reported no exercise before pregnancy had lower risk for a macrosomic infant than women who exercised. Pre-pregnancy BMI was positively associated with birth weight and risk of macrosomia but only among the least active women.

A prospective study of the association between vigorous physical activity during pregnancy and length of gestation and birthweight

Current US pregnancy-related physical activity recommendations do not provide specific guidance for vigorous intensity activity. We examined the associations between vigorous physical activity during pregnancy and length of gestation and birthweight.

METHODS

Women were recruited before 10 weeks gestation. At 13-16 weeks gestation, participants reported the type, frequency, and duration of their typical weekly vigorous physical activities. Activity domains included recreational, occupational, household, and child/adult care. Infant birth date was obtained from medical or vital records; if unavailable, self-report was used. Birthweight (from vital records) was studied among term births. We analyzed gestational age among 1,647 births using discrete-time survival analysis. We used logistic and linear regression to analyze preterm birth (birth at <37 weeks) and birthweight, respectively. Vigorous recreational activity was associated with longer gestation (any vs. none, hazard ratio (HR) [95% CI]: 0.85 [0.70, 1.05]) and we did not detect any dose-response association. Higher frequency of vigorous recreational activity sessions (adjusted for total volume of activity) was associated with a decreased odds of preterm birth (≥ 4 sessions/week vs. 0 or 1, OR [95% CI]: 0.08 (0.006, 1.0). Birthweight was not associated with physical activity measures. In summary, vigorous physical activity does not appear to be detrimental to the timing of birth or birthweight. Our data support a reduced risk of preterm birth with vigorous recreational activity, particularly with increased frequency of recreational activity sessions. Future studies should investigate the components of physical activity (i.e., intensity, duration, and frequency) in relation to birth outcomes.

Bone mineral density changes during pregnancy in actively exercising women as measured by quantitative ultrasound

Objective

To evaluate whether bone mineral density (BMD) changes in women engaged in active exercises during pregnancy would be different from non-exercising women.

Methods

Consecutive patients with singleton pregnancies who were engaged in active exercise training during pregnancy were prospectively recruited over a period of 6 months. Quantitative USG measurements of the os calcis BMD were performed at 14–20 weeks and at 36–38 weeks. These patients were compared to a control cohort of non-exercising low-risk women.

Results

A total of 24 physically active women undergoing active physical training of over 10 h per week at 20 weeks gestation and beyond (mean 13.1 h, SD 3.3) were compared to 94 non-exercising low-risk women. A marginal fall in BMD of 0.015 g/cm² (SD 0.034) was demonstrable from early to late gestation in the exercising women, which was significantly lower than that of non-exercising women (0.041 g/cm²; SD 0.042; p = 0.005). Logistic regression models confirmed that active exercises in pregnancy were significantly associated with the absence of or less BMD loss in pregnancy.

Conclusion

In women actively engaged in physical training during pregnancy, the physiological fall in BMD during pregnancy was apparently less compared to those who did not regularly exercise.

Sports and leisure time physical activity during pregnancy in nulliparous women

To describe patterns of leisure time physical activity during pregnancy in relation to pre-pregnancy leisure time physical activity, socio-demographic characteristics, fertility history, and lifestyle factors. 4,718 nulliparous with singleton pregnancy and intended spontaneous vaginal delivery were included in the study at gestational week 33 from May 2004 to July 2005. Information was provided by self-administered questionnaires. Leisure time physical activity was categorised into four categories: competitive sport, moderate-to-heavy, light or sedentary. In this population of nulliparous women, 4% participated in competitive sport, 25% in moderate-to-heavy activities, 66% in light activities, and 5% in sedentary activities in the year prior to pregnancy. Physical activity before pregnancy was statistically significantly associated with age, pre-pregnancy BMI, chronic diseases, number of years at school, and smoking habits. The proportion of women who took part in competitive sports, and moderate-to-heavy activities decreased over the three trimesters of pregnancy. The proportion of women with light physical activity was stable during pregnancy while the proportion of women with sedentary activity increased from 6% to 29%. During the third trimester women performing competitive sports or moderate-to-heavy activities before pregnancy continued to have a higher level of physical activity than women with light activities or sedentary activities before pregnancy. In general the intensity and time spent on exercise decreased during pregnancy. Women with the highest level of exercise prior to pregnancy continued to be the most active during pregnancy. Among women with sedentary activities before pregnancy one-fourth changed to light activity during pregnancy.

Leisure-time physical activity in pregnancy and the birth weight distribution: where is the effect?

BACKGROUND

Leisure-time physical activity (LTPA) is recommended during pregnancy and has been associated with lower risk of delivering a large infant. We sought to characterize the effect of LTPA across the entire birth weight distribution.

METHODS

Women enrolled in the Pregnancy Outcomes and Community Health (POUCH) Study (1998-2004) were followed-up in 2007. Follow-up efforts were extensive for a subcohort and minimal for the remainder (nonsubcohort). Thus, 596 subcohort and 418 nonsubcohort women who delivered at term participated. Offspring were categorized as small-, appropriate-, or large-for-gestational-age (SGA, AGA, and LGA, respectively) based on gender and gestational age-specific birth weight z-scores (BWz). At follow-up, women recalled pregnancy LTPA and were classified as inactive, insufficiently active or meeting LTPA recommendations. Linear, logistic, and quantile regression analyses were conducted separately by subcohort status.

RESULTS

Meeting LTPA recommendations decreased odds of LGA significantly among the nonsubcohort (aOR = 0.30, 95% CI: 0.14-0.64) and nonsignificantly among the subcohort (aOR = 0.68, 95% CI: 0.34-1.34). In quantile regression, meeting LTPA recommendations reduced BWz among the upper quantiles in the nonsubcohort.

CONCLUSIONS

LTPA during pregnancy lowered odds of LGA and reduced BWz among the upper quantiles, without shifting the entire distribution. LTPA during pregnancy may be useful for reducing risks of large fetal size.

Compliance with leisure-time physical activity recommendations in pregnant women

OBJECTIVE

The aim of this study was to identify the prevalence and factors associated with the performance of minimal beneficial leisure-time physical activity in the first half of pregnancy according to the criteria of the American College of Sport and Medicine (ACSM) and the American College of Obstetricians and Gynecologists (ACOG).

MATERIAL AND METHODS

This was a cross-sectional study carried out at the Maternal and Neonatal University Hospital in Granada, which services the whole population of the hospital reference area. We studied 1,175 healthy pregnant women aged over 18 years. Information about sociodemographics, lifestyles, obstetric antecedents and anthropometric variables were collected. The amount of leisure-time physical activity was quantified by assigning metabolic equivalents to each activity. The ACSM and ACOG criteria were used to define optimal physical activity in the first half of pregnancy. The frequency of compliance for both criteria was estimated. Multiple logistic regression models were fitted to study the factors associated with the recommendations.

RESULTS

Only 20.3% (95% confidence interval 15.50-26.10) of the women complied with ACOG criteria. More women complied with ACSM recommendations (70.8%, 95% confidence interval 67.5-73.8), which are less restrictive criteria. Women aged 30 years old or older and those with a university degree tended to devote more time to exercising according to both recommendations.

CONCLUSION

The prevalence of pregnant women who performed minimal beneficial leisure-time physical activity was lower with the dominant and more accepted criteria. It is necessary to encourage physical activity, mainly among those who are younger, and those with lower levels of educational attainment.