Spotlight on the fetus: how physical activity during pregnancy influences fetal health: a narrative review

Interval training and cardiometabolic health in reproductive-aged females

Physical activity and exercise training are especially important for reproductive-aged females as exercise-induced health benefits can also affect their infants. However, levels of physical inactivity remain high among females in this age group, before, during, and after pregnancy. There is a great need for practical and feasible exercise modes to increase adherence to exercise in this population, and interval training may be a time-efficient training modality. Interval training is a form of exercise involving intermittent bouts of intense effort interspersed with recovery periods of rest or lower-intensity exercise. A substantial amount of research indicates that interval training induces superior cardiometabolic health benefits compared with iso-energetic moderate-intensity continuous exercise. This review provides a comprehensive overview of research on interval training interventions in reproductive-aged females across various life stages, focusing on the cardiometabolic health benefits. We discuss the potential role of interval training in premenopausal females with overweight/obesity, polycystic ovary syndrome, and subfertility, as well as the potential influence of oral contraceptives on cardiometabolic adaptations to interval training. Furthermore, this review also highlights recent findings supporting the beneficial role of high-intensity interval training for cardiometabolic health outcomes during pregnancy. In summary, the existing evidence suggests that interval training can improve several cardiometabolic and reproductive outcomes in females spanning different life stages. However, more research is needed to further strengthen the evidence-base for physical activity recommendations for females in their reproductive years of life.

It's time to increase physical activity promotion among pregnant women in France

BACKGROUND

The lockdown linked to COVID-19 was shown to have negative effects on healthy behaviors in the general population, prompting the implementation of adapted public health measures. However, more vulnerable populations, such as pregnant women, were not specifically taken into account. At the time of writing this study, we know little about how the COVID-19 pandemic impacted the physical activity (PA) behavior of pregnant women in France. Given the many reports in the literature about women's low level of PA throughout pregnancy and the negative effects of the COVID-19 lockdown on behaviors in the general population; however, we might assume that their sedentary behaviors increased. The current study aimed to analyze the French recommendations and PA promotion among pregnant women.

MATERIALS AND METHODS

A literature search was done using PubMed for the key terms "physical activity/physical activity promotion," "pregnant women/pregnancy,", and "French population/France." All the relevant studies were included to support the argument for this narrative review.

RESULTS

Efforts to promote PA for pregnant women often seem ineffective and even unrealistic, and many women become overweight or obese during pregnancy. Health professionals need evidence-based guidelines and continuous training and skills development in order to convincingly encourage women to be more active during pregnancy and the postpartum period.

CONCLUSION

Health policies should strengthen PA promotion among pregnant women with detailed evidence-based guidelines on PA during postpartum.

Physical Activity Over the Lifecourse and Cardiovascular Disease

Despite improvements in cardiovascular care in recent decades, cardiovascular disease (CVD) remains a leading cause of death worldwide. At its core, CVD is a largely preventable disease with diligent risk factor management and early detection. As highlighted in the American Heart Association's Life's Essential 8, physical activity plays a central role in CVD prevention at an individual and population level. Despite pervasive knowledge of the numerous cardiovascular and noncardiovascular health benefits of physical activity, physical activity has steadily decreased over time and unfavorable changes in physical activity occur throughout people's lives. Here, we use a lifecourse framework to examine the evidence reporting on the association of physical activity with CVD. From in utero to older adults, we review and discuss the evidence detailing how physical activity may prevent incident CVD and mitigate CVD-related morbidity and death across all life stages.

Infant lung function and maternal physical activity in the first half of pregnancy

Background and aim

Physical activity (PA) in pregnancy is important for maternal and possibly offspring health. To study the early origins of lung function we aimed to determine whether PA in the first half of pregnancy is associated with lung function in healthy 3-month-old infants.

Methods

From the general population-based Preventing Atopic Dermatitis and Allergies in Children birth cohort recruiting infants antenatally in Norway and Sweden, all 812 infants (48.8% girls) with available tidal flow-volume measures in the awake state at 3 months of age and mid-pregnancy data on PA were included. PA was self-reported by the mothers and, based on intensity, we categorised them as active or inactive during pregnancy. Furthermore, we defined active mothers as fairly or highly active. The main outcome was a ratio of time to peak tidal expiratory flow to expiratory time (t _PTEF/t _E) <0.25. Associations were analysed by logistic regression, adjusting for maternal age, education, parity, pre-pregnancy body mass index, in utero nicotine exposure and parental atopy.

Results

The mean±sd t _PTEF/t _E was 0.391±0.08 and did not differ significantly according to maternal PA level in pregnancy. The 290 infants of inactive mothers had higher odds of having t _PTEF/t _E <0.25 compared to infants of all active mothers (OR 2.07, 95% CI 1.13-3.82; p=0.019) and compared to infants (n=224) of fairly active (OR 2.83, 95% CI 1.26-7.24; p=0.018) but not highly active mothers (n=298).

Conclusion

Based on self-reported maternal PA in the first half of pregnancy, 3-month-old infants of inactive compared to active mothers had higher odds of a low t _PTEF/t _E.

"Conscious Nine Months": Exploring Regular Physical Activity amongst Pregnant Women-A Qualitative Study Protocol

Despite a clear and convincing evidence base and strong recommendations for pregnant women to maintain regular moderate physical activity throughout pregnancy, many of them reduce or discontinue exercise altogether. This is due to pregnancy-related difficulties and barriers. The aim of this protocol is to describe a qualitative research methodology for a study exploring the experiences of women who managed to achieve the recommended levels of physical activity throughout their pregnancy by regularly participating in a specially designed "Conscious nine months" exercise programme. A qualitative descriptive design will be used, including semi-structured in-depth literature-based interviews, together with thematic analysis. Consolidated criteria for reporting qualitative research (COREQ) guidelines will be used. In-depth individual interviews (60-90 min) with exercise programme participants, used together with a thematic analysis process, will allow for a better understanding and exploration of what enabled the participants to achieve such high adherence to the overall exercise programme. The chosen methodology offers a structured way for researchers to explore the experiences and factors that influence the ability of pregnant women to be physically active, enabling research into how pregnant women can be supported to remain active during this special, often challenging time in life.

Mother’s physical activity during pregnancy and newborn’s brain cortical development

Background

Physical activity is known to improve mental health, and is regarded as safe and desirable for uncomplicated pregnancy. In this novel study, we aim to evaluate whether there are associations between maternal physical activity during pregnancy and neonatal brain cortical development.

Methods

Forty-four mother/newborn dyads were included in this longitudinal study. Healthy pregnant women were recruited and their physical activity throughout pregnancy were documented using accelerometers worn for 3–7 days for each of the 6 time points at 4–10, ∼12, ∼18, ∼24, ∼30, and ∼36 weeks of pregnancy. Average daily total steps and daily total activity count as well as daily minutes spent in sedentary/light/moderate/vigorous activity modes were extracted from the accelerometers for each time point. At ∼2 weeks of postnatal age, their newborns underwent an MRI examination of the brain without sedation, and 3D T1-weighted brain structural images were post-processed by the iBEAT2.0 software utilizing advanced deep learning approaches. Cortical surface maps were reconstructed from the segmented brain images and parcellated to 34 regions in each brain hemisphere, and mean cortical thickness for each region was computed for partial correlation analyses with physical activity measures, with appropriate multiple comparison corrections and potential confounders controlled.

Results

At 4–10 weeks of pregnancy, mother’s daily total activity count positively correlated (FDR corrected P ≤ 0.05) with newborn’s cortical thickness in the left caudal middle frontal gyrus (rho = 0.48, P = 0.04), right medial orbital frontal gyrus (rho = 0.48, P = 0.04), and right transverse temporal gyrus (rho = 0.48, P = 0.04); mother’s daily time in moderate activity mode positively correlated with newborn’s cortical thickness in the right transverse temporal gyrus (rho = 0.53, P = 0.03). At ∼24 weeks of pregnancy, mother’s daily total activity count positively correlated (FDR corrected P ≤ 0.05) with newborn’s cortical thickness in the left (rho = 0.56, P = 0.02) and right isthmus cingulate gyrus (rho = 0.50, P = 0.05).

Conclusion

We identified significant relationships between physical activity in healthy pregnant women during the 1st and 2nd trimester and brain cortical development in newborns. Higher maternal physical activity level is associated with greater neonatal brain cortical thickness, presumably indicating better cortical development.

To Be Active or to Stop? A Cross-Sectional Retrospective Study Exploring Provider Advice and Patient Fears Surrounding Physical Activity in Pregnancies Complicated by Fetal Growth Restriction

Exercise guidance for women with pregnancies complicated by fetal growth restriction (FGR) is vague, despite the fact that physical activity during pregnancy improves placental development, placental blood flow, and encourages healthy fetal growth. The goal of this study is to test the hypothesis that women with pregnancies complicated by FGR are fearful of physical activity and are being given unclear or limited advice from healthcare providers. Participants (N = 78) (women who delivered an infant diagnosed with FGR within the past 5 years) took an electronic survey including demographic information, pregnancy information, provider advice recall, and other health-related information relevant to growth-restricted pregnancies. Quantitative and qualitative (post-positivism paradigm) methods were employed to analyze the data. When asked specifically about how the FGR diagnosis impacted their activity levels, nearly 50% of participants said the diagnosis led them to decrease their activity levels. Participants reported that healthcare providers who do discuss activity with pregnant patients with FGR suggest low-intensity activities or ceasing activity, although the majority of providers did not discuss activity at all. More fears surrounding physical activity were reported post-FGR diagnosis, including worrying about fetal growth and development and causing fetal harm when engaging in physical activity.

Activity restriction and preterm birth prevention

PURPOSE OF REVIEW

Since the 1900s, activity restriction (AR) has been widely prescribed as a strategy for preventing preterm birth (PTB). Over the past decade, the practice has been called into question as numerous studies have demonstrated that AR does not improve obstetrical and perinatal outcomes but does confer significant physical and psychological risks. The purpose of this review is to offer clinicians a summary of the latest data on the risks, benefits, and efficacy of AR for the prevention of PTB.

RECENT FINDINGS

Both retrospective and prospective studies have demonstrated that AR does not significantly prolong pregnancy including those with multiple gestations, short cervices, ruptured membranes, and increased body mass indexes. Several studies have also shown that physical activity during pregnancy is associated with a higher incidence of vaginal delivery, a lower incidence of gestational diabetes mellitus, and a lower incidence of hypertensive disorders without increasing the risk of adverse neonatal outcomes.

SUMMARY

The culmination of these data led to the Society for Maternal-Fetal Medicines' release of an updated committee recommendation in August of 2020; AR should not be routinely prescribed as a treatment to prevent PTB.

Effects of Regular Exercise During Pregnancy on Early Childhood Neurodevelopment: The Physical Activity for Mothers Enrolled in Longitudinal Analysis Randomized Controlled Trial

BACKGROUND

The aim of this study was to investigate the effect of exercise during pregnancy on early childhood neurodevelopment (cognitive, motor, and language domains).

METHODS

A randomized controlled trial nested into the 2015 Pelotas (Brazil) Birth Cohort was conducted. Healthy pregnant women were enrolled between 16 and 20 weeks of gestation; 424 women and their children (intervention [n = 141]; control [n = 283]) were analyzed. An exercise-based intervention 3 times per week was delivered over 16 weeks. Child neurodevelopment and its domains were assessed at 1, 2, and 4 years. Standardized mean differences and 95% confidence intervals are presented.

RESULTS

No effects of exercise during pregnancy on child neurodevelopment and its domains at age 1 year were observed. Compared with the control group, children from women in the exercise group had higher language score at age 2 years (standardized mean differences = 0.23; 95% confidence intervals, 0.02 to 0.44) and higher cognitive score (standardized mean differences = 0.22; 95% confidence intervals, 0.03 to 0.41) at age 4 years. No effects of exercise during pregnancy were observed in the motor domain at 1, 2, and 4 years.

CONCLUSIONS

No detrimental effects of exercise during pregnancy on child neurodevelopment were observed. In addition, these findings suggest that exercise during pregnancy can result in small benefits for language and cognitive development.

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.

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

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

The first prior: From co-embodiment to co-homeostasis in early life

The idea that our perceptions in the here and now are influenced by prior events and experiences has recently received substantial support and attention from the proponents of the Predictive Processing (PP) and Active Inference framework in philosophy and computational neuroscience. In this paper we look at how perceptual experiences get off the ground from the outset, in utero. One basic yet overlooked aspect of current PP approaches is that human organisms first develop within another human body. Crucially, while not all humans will have the experience of being pregnant or carrying a baby, the experience of being carried and growing within another person's body is universal. Specifically, we focus on the development of minimal selfhood in utero as a process co-embodiment and co-homeostasis, and highlight their close relationship. We conclude with some implications on several critical questions fuelling current debates on the nature of conscious experiences, minimal self and social cognition.

Embryonic movement stimulates joint formation and development: Implications in arthrogryposis multiplex congenita

Arthrogryposis multiplex congenita (AMC) is a heterogeneous syndrome where multiple joints have reduced range of motion due to contracture formation prior to birth. A common cause of AMC is reduced embryonic movement in utero. This reduction in embryonic movement can perturb molecular mechanisms and signaling pathways involved in the formation of joints during development. The absence of mechanical stimuli can impair joint cavitation, resulting in joint fusion, and ultimately eliminate function. In turn, mechanical stimuli are critical for proper joint formation during development and for mitigating AMC. Studies in experimental animal models have provided a greater understanding on the molecular pathophysiology of congenital contracture formation as a consequence of embryonic immobilization. Elucidation of how the mechanical signaling environment is transduced to initiate a biological response will be necessary to gain a deeper understanding of how mechanical stimuli are intertwined in the molecular regulation of joint development.