Thermoregulation During Pregnancy: a Controlled Trial Investigating the Risk of Maternal Hyperthermia During Exercise in the Heat

Smallcombe, James W.; Puhenthirar, Agalyaa; Casasola, William; Inoue, Daniela Sayuri; Chaseling, Georgia K.; Ravanelli, Nicholas; Edwards, Kate M.; Jay, Ollie

doi:10.1007/s40279-021-01504-y

Cited by 15 publications

(14 citation statements)

References 40 publications

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“…The effect of prolonged exercise and chronic heat exposure that may occur among pregnant women who work outdoors in hot countries is currently unknown and requires further study. Research evidence is so far consistent with current advice, such as that from the International Olympic Committee, that pregnant women can safely exercise for short periods of time in moderate temperatures (Bø et al 2016;Smallcombe et al 2021).…”

Section: Discussionsupporting

confidence: 65%

“…Studies have shown that short-term exposure to heat through exercise or in a sauna or hot bath does not raise a pregnant woman’s temperature over the teratogenic threshold of an increase in 1.5 °C; Ravanelli et al ( 2018 ) demonstrated in a review paper that pregnant women can use a hot bath of 40 °C or a dry sauna of 70 °C for 20 min and maintain their temperature within safe limits. Furthermore, Smallcombe et al ( 2021 ) recently demonstrated no systematic alteration in thermoregulatory capacity among pregnant women in the second or third trimester performing moderate intensity exercise for up to 45 min in the heat (32 °C, relative humidity 45%) as compared to non-pregnant controls. However, whether there are adverse effects of prolonged exercise or physical labour in a hot environment is not yet known and the temperature thresholds at which adverse effects may occur are not well described.…”

Section: Resultsmentioning

confidence: 98%

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Physiological mechanisms of the impact of heat during pregnancy and the clinical implications: review of the evidence from an expert group meeting

et al. 2022

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Many populations experience high seasonal temperatures. Pregnant women are considered vulnerable to extreme heat because ambient heat exposure has been linked to pregnancy complications including preterm birth and low birthweight. The physiological mechanisms that underpin these associations are poorly understood. We reviewed the existing research evidence to clarify the mechanisms that lead to adverse pregnancy outcomes in order to inform public health actions. A multi-disciplinary expert group met to review the existing evidence base and formulate a consensus regarding the physiological mechanisms that mediate the effect of high ambient temperature on pregnancy. A literature search was conducted in advance of the meeting to identify existing hypotheses and develop a series of questions and themes for discussion. Numerous hypotheses have been generated based on animal models and limited observational studies. There is growing evidence that pregnant women are able to appropriately thermoregulate; however, when exposed to extreme heat, there are a number of processes that may occur which could harm the mother or fetus including a reduction in placental blood flow, dehydration, and an inflammatory response that may trigger preterm birth. There is a lack of substantial evidence regarding the processes that cause heat exposure to harm pregnant women. Research is urgently needed to identify what causes the adverse outcomes in pregnancy related to high ambient temperatures so that the impact of climate change on pregnant women can be mitigated.

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Section: Discussionsupporting

confidence: 65%

Section: Resultsmentioning

confidence: 98%

Physiological mechanisms of the impact of heat during pregnancy and the clinical implications: review of the evidence from an expert group meeting

et al. 2022

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“…Other studies have mainly focused on thermoregulation in pregnancy and there are several studies with encouraging evidence that thermoregulation is not compromised. (22,23) Although there is clear evidence that moderate intensity exercise is of benefit in pregnancy,(24) these studies are in temperate conditions and so not transferable to our setting. Additionally in extreme cases (Olympic athletes exercising at > 90% maximum maternal heart rate) there can be compromised fetal wellbeing.…”

Section: Discussionmentioning

confidence: 99%

Exploring the use of UmbiFlow^™ to assess the impact of heat stress on fetoplacental blood flow in field studies

Bonell

Vannevel

Sonko

et al. 2022

Preprint

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ObjectiveTo evaluate the impact of heat stress on umbilical artery resistance index (RI) measured by UmbiFlow™ in field settings and the implications for pregnancy outcomes.MethodsThis feasibility study was conducted in West Kiang, The Gambia, West Africa; a rural area with increasing exposure to extreme heat. We recruited women with singleton fetuses who performed manual tasks (such as farming) during pregnancy. The umbilical artery RI was measured at rest, during and at the end of a typical working shift in women ≥ 28 weeks’ gestation. Adverse pregnancy outcomes (APO) were classified as stillbirth, preterm birth, low birth weight, or small for gestational age, and all other outcomes as normal.ResultsA total of 40 participants were included; 23 normal births and 17 APO. Umbilical artery RI demonstrated a nonlinear relationship to heat stress, with indication of a potential threshold value for placental insufficiency around 32ºC by universal thermal climate index. Preliminary evidence suggests the fetoplacental circulation response to heat stress differs in APO versus normal outcome.ConclusionsThe Umbiflow™ device proved to be an effective field method for assessing placental function. Dynamic changes in RI may begin to explain the association between extreme heat and APO.FundingThe Wellcome Trust (216336/Z/19/Z)SynopsisExtreme heat exposure is increasing and a low-cost umbilical artery doppler device, UmbiFlow™, can aid understanding of fetoplacental function under heat stress conditions.

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“…Excessive heat exposure to pregnant women during the later stages of pregnancy is associated with increased risk of still‐ and premature births (Chersich et al., 2020; S. Ha et al., 2017), yet moderate bouts of exercise in the second and third trimesters were recently shown to not pose a greater risk to pregnant women in those trimesters (Smallcombe et al., 2021).…”

Section: Assessing the Impacts Of Overheating On Urban Vulnerabilitymentioning

confidence: 99%

Integrated Assessment of Urban Overheating Impacts on Human Life

et al. 2022

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Urban overheating, driven by global climate change and urban development, is a major contemporary challenge that substantially impacts urban livability and sustainability. Overheating represents a multifaceted threat to the well‐being, performance, and health of individuals as well as the energy efficiency and economy of cities, and it is influenced by complex interactions between building, city, and global scale climates. In recent decades, extensive discipline‐specific research has characterized urban heat and assessed its implications on human life, including ongoing efforts to bridge neighboring disciplines. The research horizon now encompasses complex problems involving a wide range of disciplines, and therefore comprehensive and integrated assessments are needed that address such interdisciplinarity. Here, our objective is to go beyond a review of existing literature and instead provide a broad overview and integrated assessments of urban overheating, defining holistic pathways for addressing the impacts on human life. We (a) detail the characterization of heat hazards and exposure across different scales and in various disciplines, (b) identify individual sensitivities to urban overheating that increase vulnerability and cause adverse impacts in different populations, (c) elaborate on adaptive capacities that individuals and cities can adopt, (d) document the impacts of urban overheating on health and energy, and (e) discuss frontiers of theoretical and applied urban climatology, built environment design, and governance toward reduction of heat exposure and vulnerability at various scales. The most critical challenges in future research and application are identified, targeting both the gaps and the need for greater integration in overheating assessments.

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Thermoregulation During Pregnancy: a Controlled Trial Investigating the Risk of Maternal Hyperthermia During Exercise in the Heat

Cited by 15 publications

References 40 publications

Physiological mechanisms of the impact of heat during pregnancy and the clinical implications: review of the evidence from an expert group meeting

Physiological mechanisms of the impact of heat during pregnancy and the clinical implications: review of the evidence from an expert group meeting

Exploring the use of UmbiFlow^™ to assess the impact of heat stress on fetoplacental blood flow in field studies

Integrated Assessment of Urban Overheating Impacts on Human Life

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Thermoregulation During Pregnancy: a Controlled Trial Investigating the Risk of Maternal Hyperthermia During Exercise in the Heat

Cited by 15 publications

References 40 publications

Physiological mechanisms of the impact of heat during pregnancy and the clinical implications: review of the evidence from an expert group meeting

Physiological mechanisms of the impact of heat during pregnancy and the clinical implications: review of the evidence from an expert group meeting

Exploring the use of UmbiFlow™ to assess the impact of heat stress on fetoplacental blood flow in field studies

Integrated Assessment of Urban Overheating Impacts on Human Life

Contact Info

Product

Resources

About

Exploring the use of UmbiFlow^™ to assess the impact of heat stress on fetoplacental blood flow in field studies