Temperature and preeclampsia: Epidemiological evidence that perturbation in maternal heat homeostasis affects pregnancy outcome

Maternal exposure to bioclimatic stress and hypertensive disorders of pregnancy in Western Australia: identifying potential critical windows of susceptibility

The anthropogenic climate change may impact pregnancy outcomes. Rather than ambient temperature, we aimed to use a composite bioclimatic metric (Universal Thermal Climate Index, UTCI) to identify critical susceptible windows for the associations between bioclimatic exposure and hypertensive disorders of pregnancy (HDPs) risk. Daily UTCI exposure from 12 weeks of preconception through pregnancy was linked to 415,091 singleton pregnancies between 1st January 2000 and 31st December 2015 in Western Australia. Adjusted weekly-specific and cumulative odds ratios (ORs) and 95% confidence intervals (CIs) of gestational hypertension and preeclampsia were estimated with distributed lag non-linear and standard non-linear logistic regressions. Exposures from early pregnancy to week 30 were associated with greater odds of HDPs with critical susceptible windows, particularly elevated at the 1st (10.2 °C) and 99th (26.0 °C) exposure centiles as compared to the median (14.2 °C). The most elevated ORs were 1.07 (95% CI 1.06, 1.08) in weeks 8-18 for gestational hypertension and 1.10 (95% CI 1.08, 1.11) in weeks 11-16 for preeclampsia for the 99th exposure centile. Cumulative exposures associated with HDPs with relatively higher but less precise ORs. The effects of high exposure to HDPs indicated sociodemographic inequalities. The identified critical periods and subpopulations could benefit from climate-related interventions.

Understanding the physiological and biological response to ambient heat exposure in pregnancy: protocol for a systematic review and meta-analysis

INTRODUCTION

Climate change increases not only the frequency, intensity and duration of extreme heat events but also annual temperatures globally, resulting in many negative health effects, including harmful effects on pregnancy and pregnancy outcomes. As temperatures continue to increase precipitously, there is a growing need to understand the underlying biological pathways of this association. This systematic review will focus on maternal, placental and fetal changes that occur in pregnancy due to environmental heat stress exposure, in order to identify the evidence-based pathways that play a role in this association.

METHODS AND ANALYSIS

We will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We will search PubMed and Ovid Embase databases from inception using tested and validated search algorithms. Inclusion of any studies that involve pregnant women and have measured environmental heat stress exposure and either maternal, placental or fetal physiological or biochemical changes and are available in English. Modelling studies or those with only animals will be excluded. The risk of bias will be assessed using the Office of Health Assessment and Translation tool. Abstract screening, data extraction and risk of bias assessment will be conducted by two independent reviewers.Environmental parameters will be reported for each study and where possible these will be combined to calculate a heat stress indicator to allow comparison of exposure between studies. A narrative synthesis will be presented following standard guidelines. Where outcome measures have at least two levels of exposure, we will conduct a dose-response meta-analysis should there be at least three studies with the same outcome. A random effects meta-analysis will be conducted where at least three studies give the same outcome.

ETHICS AND DISSEMINATION

This systematic review and meta-analysis does not require ethical approval. Dissemination will be through peer-reviewed journal publication and presentation at international conferences/interest groups.

PROSPERO REGISTRATION NUMBER

CRD42024511153.

Ambient temperature-related sex ratio at birth in historical urban populations: the example of the city of Poznań, 1848-1900

This study examines whether exposure to ambient temperature in nineteenth-century urban space affected the ratio of boys to girls at birth. Furthermore, we investigate the details of temperature effects timing upon sex ratio at birth. The research included 66,009 individual births, aggregated in subsequent months of births for the years 1847-1900, i.e. 33,922 boys and 32,087 girls. The statistical modelling of the probability of a girl being born is based on logistic GAM with penalized splines and automatically selected complexity. Our research emphasizes the significant effect of temperature in the year of conception: the higher the temperature was, the smaller probability of a girl being born was observed. There were also several significant temperature lags before conception and during pregnancy. Our findings indicate that in the past, ambient temperature, similar to psychological stress, hunger, malnutrition, and social and economic factors, influenced the viability of a foetus. Research on the effects of climate on the sex ratio in historical populations may allow for a better understanding of the relationship between environmental factors and reproduction, especially concerning historical populations since due to some cultural limitations, they were more prone to stronger environmental stressors than currently.

Impacts of heat exposure in utero on long-term health and social outcomes: a systematic review

BACKGROUND

Climate change, particularly global warming, is amongst the greatest threats to human health. While short-term effects of heat exposure in pregnancy, such as preterm birth, are well documented, long-term effects have received less attention. This review aims to systematically assess evidence on the long-term impacts on the foetus of heat exposure in utero.

METHODS

A search was conducted in August 2019 and updated in April 2023 in MEDLINE(PubMed). We included studies on the relationship of environmental heat exposure during pregnancy and any long-term outcomes. Risk of bias was assessed using tools developed by the Joanna-Briggs Institute, and the evidence was appraised using the GRADE approach. Synthesis without Meta-Analysis (SWiM) guidelines were used.

RESULTS

Eighteen thousand six hundred twenty one records were screened, with 29 studies included across six outcome groups. Studies were mostly conducted in high-income countries (n = 16/25), in cooler climates. All studies were observational, with 17 cohort, 5 case-control and 8 cross-sectional studies. The timeline of the data is from 1913 to 2019, and individuals ranged in age from neonates to adults, and the elderly. Increasing heat exposure during pregnancy was associated with decreased earnings and lower educational attainment (n = 4/6), as well as worsened cardiovascular (n = 3/6), respiratory (n = 3/3), psychiatric (n = 7/12) and anthropometric (n = 2/2) outcomes, possibly culminating in increased overall mortality (n = 2/3). The effect on female infants was greater than on males in 8 of 9 studies differentiating by sex. The quality of evidence was low in respiratory and longevity outcome groups to very low in all others.

CONCLUSIONS

Increasing heat exposure was associated with a multitude of detrimental outcomes across diverse body systems. The biological pathways involved are yet to be elucidated, but could include epigenetic and developmental perturbations, through interactions with the placenta and inflammation. This highlights the need for further research into the long-term effects of heat exposure, biological pathways, and possible adaptation strategies in studies, particularly in neglected regions. Heat exposure in-utero has the potential to compound existing health and social inequalities. Poor study design of the included studies constrains the conclusions of this review, with heterogenous exposure measures and outcomes rendering comparisons across contexts/studies difficult.

TRIAL REGISTRATION

PROSPERO CRD 42019140136.

Heat stress and adverse pregnancy outcome: Prospective cohort study

OBJECTIVE

To explore the relationship between occupational heat exposure, physiological heat strain indicators and adverse outcomes in pregnant women.

DESIGN

Prospective cohort.

SETTING

Workplaces in Tamil Nadu, India.

SAMPLE

A cohort of 800 pregnant women engaged in moderate to heavy physical work in 2017-2019 and 2021-2022.

METHODS

Participants were recruited at between 8 and 14 weeks of gestation. Occupational heat exposure and heat strain indicators were captured each trimester. 'Heat exposed' was defined as heat stress exceeding the threshold limit value (TLV) for safe manual work (with maximum wet-bulb globe temperatures of 27.5°C for a heavy workload and 28.0°C for a moderate workload). Physiological heat strain indicators (HSIs) such as core body temperature (CBT) and urine specific gravity (USG) were measured before and after each shift. Heat-related health symptoms were captured using the modified HOTHAPS questionnaire.

MAIN OUTCOME MEASURES

The main outcome measures included (1) a composite measure of any adverse pregnancy outcome (APO) during pregnancy (including miscarriage, preterm birth, low birthweight, stillbirth, intrauterine growth restriction and birth defects), (2) a composite measure of adverse outcomes at birth (3) and miscarriage.

RESULTS

Of the 800 participants, 47.3% had high occupational heat exposure. A rise in CBT was recorded in 17.4% of exposed workers, and 29.6% of workers experienced moderate dehydration (USG ≥ 1.020). Heat-exposed women had a doubled risk of miscarriage (adjusted odds ratio, aOR 2.4; 95% confidence interval, 95% CI 1.0-5.7). High occupational heat exposure was associated with an increased risk of any adverse pregnancy and foetal outcome (aOR 2.3; 95% CI 1.4-3.8) and adverse outcome at birth (aOR 2.0; 95% CI 1.2-3.3).

CONCLUSIONS

High occupational heat exposure is associated with HSIs and adverse pregnancy outcomes in India.

Indoor Temperature and Energy Insecurity: Implications for Prenatal Health Disparities in Extreme Heat Events

BACKGROUND

Extreme heat events are a major public health concern and are only expected to increase in intensity and severity as climate change continues to accelerate. Pregnant people are physiologically more vulnerable to the effects of extreme heat, and exposure can induce harm on both the pregnant person and the fetus.

OBJECTIVES

This commentary argues that there is a need for greater epidemiological research on indoor heat exposure and energy insecurity as potential drivers of maternal and child environmental health disparities.

DISCUSSION

While there is substantial evidence linking ambient (outdoor) high temperature to pregnancy-related outcomes, there is a lack of epidemiological evidence to date on pregnant people's exposure to high indoor temperature and adverse maternal and/or child health outcomes. Energy insecurity is disproportionately experienced by people with low incomes and/or people of color, and indoor temperature may play a role in shaping socioeconomic and racial/ethnic disparities in maternal and child health in the United States. Further research is needed to understand the relationship between indoor heat exposure, energy insecurity, and pregnancy outcomes in both parents and children and to inform potential policies and practices to enhance resilience and reduce maternal/child health disparities. https://doi.org/10.1289/EHP13706.

Disparities in the association between ambient temperature and preterm birth according to individual and regional characteristics: a nationwide time-stratified case-crossover study

BACKGROUND

Several studies have reported that climate change elevates heat exposure in pregnant women and high temperatures during pregnancy are associated with preterm births (PTBs). Although the association might be disproportionate, related evidence remains sparse. We evaluated the disproportionate risk of PTB associated with ambient temperature during pregnancy by individual and regional characteristics in South Korea.

METHODS

We collected data on birth certificates and daily mean temperatures during the period from 2011 to 2019. A time-stratified case-crossover design was used to investigate the association between temperature and PTB and stratified analyses were conducted to examine the effect modification of individual and regional characteristics.

RESULTS

A total of 160,067 singleton PTBs were recorded in Korea from 2011 to 2019. A 5℃ increase in the mean temperature during the last four weeks before delivery was associated with an increased risk of PTB with an odds ratio (OR) of 1.03 (95% confidence interval [CI]: 1.02, 1.05), and the association was more evident in mothers aged ≥35 years (OR: 1.06 [95% CI: 1.03, 1.10]) and with low education levels (OR: 1.04 [95% CI: 1.02, 1.05]). Additionally, the estimated risk was evident in districts with lower medical resources and more prominent disparities were shown by individual and regional characteristics in rural areas than in urban areas.

CONCLUSIONS

This study provides evidence that the risk of PTB related to ambient temperature is disproportionate by individual and regional characteristics and suggests the need for public health policies to alleviate the disparities, especially in rural areas.

Ambient temperature and preeclampsia: A historical cohort study

Previous studies found inconsistent associations between ambient temperature during pregnancy and the risk of preeclampsia. If such associations are causal, they may impact the future burden of preeclampsia in the context of climate change. We used a historical cohort of 129,009 pregnancies (5074 preeclampsia cases) from southern Israel that was merged with temperature assessments from a hybrid satellite-based exposure model. Distributed-lag and cause-specific hazard models were employed to study time to all preeclampsia cases, followed by stratification according to early (≤34 weeks) and late (>34 weeks) onset disease and identify critical exposure periods. We found a positive association between temperature and preeclampsia during gestation, which was stronger in the 3rd trimester. For example, during week 33, compared to the reference temperature of 22.4 °C, the cause-specific hazard ratio (HRCS) of preeclampsia was 1.01 (95% confidence interval (CI): 1.01-1.02) when exposed to 30 °C, 1.05 (95%CI: 1.03-1.08) at 35 °C, and 1.07 (95%CI: 1.04-1.10) at 37 °C. The associations existed with both early- and late-onset preeclampsia; however, the associations with the early-onset disease were somewhat stronger, limited to the first weeks of pregnancy and the third trimester, and with larger confidence intervals. The HRCS for early preeclampsia onset, when exposed to 37 °C compared to 22.4 °C during week 33, was 1.12 (95%CI: 0.96-1.30), and for late-onset preeclampsia, the HRCS was 1.09 (95%CI: 1.05-1.13). To conclude, exposure to high temperatures at the beginning and, particularly, the end of gestation is associated with an increased risk of preeclampsia in southern Israel.

Associations between extreme temperature exposure and hypertensive disorders in pregnancy: a systematic review and meta-analysis

BACKGROUND

Hypertensive disorders in pregnancy (HDP) are a major cause of maternal mortality and morbidity. Recent studies indicated that pregnant women are the most vulnerable populations to ambient temperature influences, but it affected HDP with inconsistent conclusions. Our objective is to systematically review whether extreme temperature exposure is associated with a changed risk for HDP.

METHOD

We searched PubMed, EMBASE, Web of Science and Cochrane Library databases. We included cohort or case control studies examining the association between extreme temperature exposure before or during pregnancy and HDP. Heat sources such as saunas and hot baths were excluded. We pooled the odds ratio (OR) to assess the association between extreme temperature exposure and preeclampsia or eclampsia.

RESULTS

Fifteen studies involving 4,481,888 patients were included. Five studies were included in the meta-analysis. The overall result demonstrated that in the first half of pregnancy, heat exposure increases the risk of developing preeclampsia or eclampsia and gestational hypertension, and cold exposure decreases the risk. The meta-analysis revealed that during the first half of pregnancy, heat exposure increased the risk of preeclampsia or eclampsia (OR 1.54, 95% confidence interval (CI): 1.10, 2.15), whereas cold exposure decreased the risk (OR 0.90, 95% CI: 0.84, 0.97).

CONCLUSION

The ambient temperature is an important determinant for the development of HDP, especially for preeclampsia or eclampsia. The effects of extreme temperatures may be bidirectional during the different trimesters of pregnancy, which should be evaluated by future studies. This review provided hints of temperature regulation in HDP administration.

Adverse effects of temperature on perinatal and pregnancy outcomes: methodological challenges and knowledge gaps

Evidence linking temperature with adverse perinatal and pregnancy outcomes is emerging. We searched for literature published until 30 January 2023 in PubMed, Web of Science, and reference lists of articles focusing on the outcomes that were most studied like preterm birth, low birth weight, stillbirth, and hypertensive disorders of pregnancy. A review of the literature reveals important gaps in knowledge and several methodological challenges. One important gap is the lack of knowledge of how core body temperature modulates under extreme ambient temperature exposure during pregnancy. We do not know the magnitude of non-modulation of body temperature during pregnancy that is clinically significant, i.e., when the body starts triggering physiologic counterbalances. Furthermore, few studies are conducted in places where extreme temperature conditions are more frequently encountered, such as in South Asia and sub-Saharan Africa. Little is also known about specific cost-effective interventions that can be implemented in vulnerable communities to reduce adverse outcomes. As the threat of global warming looms large, effective interventions are critically necessary to mitigate its effects.

A Comprehensive Review on Hot Ambient Temperature and its Impacts on Adverse Pregnancy Outcomes

INTRODUCTION

High workplace/ambient temperatures have been associated with Adverse Pregnancy Outcomes (APO). Millions of women working in developing nations suffer due to the rising temperatures caused by climate change. There are few pieces of research linking occupational heat stress to APO, and fresh evidence is required.

METHODOLOGY

We used databases including PubMed, Google Scholar, and Science Direct to search for research on high ambient/workplace temperatures and their effects. Original articles, newsletters, and book chapters were examined. The literature we analysed was categorised as follows: Heat, strain, and physical activity harming both mother and fetus. After categorising the literature, it was examined to identify the major results.

RESULTS

We found a definite association between heat stress and APOs such as miscarriages, premature birth, stillbirth, low birthweight, and congenital abnormalities in 23 research articles. Our work provides important information for future research into the biological mechanisms that create APOs and various prevention measures.

CONCLUSION

Our data suggest that temperature has long-term and short-term effects on maternal and fetal health. Though small in number, this study stressed the need for bigger cohort studies in tropical developing countries to create evidence for coordinated policies to safeguard pregnant women.

The Impact of Extreme Heat Exposure on Pregnant People and Neonates: A State of the Science Review

The relationship between heat exposure and perinatal morbidity and mortality is of increasing concern as global temperatures rise and extreme heat events become more frequent and intense. Heat exposure can lead to a multitude of harmful outcomes for pregnant individuals and neonates, including hospitalization and death. This state of the science review explored the evidence on the associations between heat exposure and negative health outcomes during pregnancy and the neonatal period. Findings suggest that improving health care provider and patient awareness of heat-related risks and implementing specific interventions could mitigate adverse outcomes. Furthermore, public health and other policy interventions are needed to increase thermal comfort and reduce societal exposure to extreme heat and related risks. Early warning systems, medical alerts, provider and patient education, and increased access to health care and thermal comfort may improve pregnancy and early life health outcomes.

Factors influencing vulnerability to climate change-related health impacts in cities - A conceptual framework

Climate change will have adverse impacts on human health, which are amplified in cities. For these impacts, there are direct, indirect, and deferred pathways. The first category is well-studied, while indirect and deferred impacts are not well-understood. Moreover, the factors moderating the impacts have received little attention, although understanding these factors is critical for adaptation. We developed a conceptual framework that shows the pathways of climate impacts on human health, focusing specifically on the factors of urban environment moderating the emergence and severity of these health impacts. Based on the framework and literature review, we illustrate the mechanisms of direct, indirect, and deferred health impact occurrence and the factors that exacerbate or alleviate the severity of these impacts, thus presenting valuable insights for anticipatory adaptation. We conclude that an integrated systemic approach to preventing health risks from climate change can provide co-benefits for adaptation and address multiple health risks. Such an approach should be mainstreamed horizontally to all sectors of urban planning and should account for the spatiotemporal aspects of policy and planning decisions and city complexity.

Early delivery following chronic and acute ambient temperature exposure: a comprehensive survival approach

Background

Ambient temperature, particularly heat, is increasingly acknowledged as a trigger for preterm delivery but study designs have been limited and results mixed. We aimed to comprehensively evaluate the association between ambient temperature throughout pregnancy and preterm delivery.

Methods

We estimated daily temperature throughout pregnancy using a cutting-edge spatiotemporal model for 5347 live singleton births from three prospective cohorts in France, 2002–2018. We performed Cox regression (survival analysis) with distributed lags to evaluate time-varying associations with preterm birth simultaneously controlling for exposure during the first 26 weeks and last 30 days of pregnancy. We examined weekly mean, daytime, night-time and variability of temperature, and heatwaves accounting for adaptation to location and season.

Results

Preterm birth risk was higher following cold (5th vs 50th percentile of mean temperature) 7–9 weeks after conception [relative risk (RR): 1.3, 95% CI: 1.0–1.6 for 2°C vs 11.6°C] and 10–4 days before delivery (RR: 1.6, 95% CI: 1.1–2.1 for 1.2°C vs 12.1°C). Night-time heat (95th vs 50th percentile of minimum temperature; 15.7°C vs 7.4°C) increased risk when exposure occurred within 5 weeks of conception (RR: 2.0, 95% CI: 1.05–3.8) or 20–26 weeks after conception (RR: 2.9, 95% CI: 1.2–6.8). Overall and daytime heat (high mean and maximum temperature) showed consistent effects. We found no clear associations with temperature variability or heatwave indicators, suggesting they may be less relevant for preterm birth.

Conclusions

In a temperate climate, night-time heat and chronic and acute cold exposures were associated with increased risk of preterm birth. These results suggest night-time heat as a relevant indicator. In the context of rising temperatures and more frequent weather hazards, these results should inform public health policies to reduce the growing burden of preterm births.

Ambient temperature during pregnancy and risk of maternal hypertensive disorders: A time-to-event study in Johannesburg, South Africa

Hypertensive disorders in pregnancy are a leading cause of maternal and perinatal mortality and morbidity. We evaluate the effects of ambient temperature on risk of maternal hypertensive disorders throughout pregnancy. We used birth register data for all singleton births (22-43 weeks' gestation) recorded at a tertiary-level hospital in Johannesburg, South Africa, between July 2017-June 2018. Time-to-event analysis was combined with distributed lag non-linear models to examine the effects of mean weekly temperature, from conception to birth, on risk of (i) high blood pressure, hypertension, or gestational hypertension, and (ii) pre-eclampsia, eclampsia, or HELLP (hemolysis, elevated liver enzymes, low platelets). Low and high temperatures were defined as the 5th and 95th percentiles of daily mean temperature, respectively. Of 7986 women included, 844 (10.6%) had a hypertensive disorder of which 432 (51.2%) had high blood pressure/hypertension/gestational hypertension and 412 (48.8%) had pre-eclampsia/eclampsia/HELLP. High temperature in early pregnancy was associated with an increased risk of pre-eclampsia/eclampsia/HELLP. High temperature (23 °C vs 18 °C) in the third and fourth weeks of pregnancy posed the greatest risk, with hazard ratios of 1.76 (95% CI 1.12-2.78) and 1.79 (95% CI 1.19-2.71), respectively. Whereas, high temperatures in mid-late pregnancy tended to protect against pre-eclampsia/eclampsia/HELLP. Low temperature (11°) during the third trimester (from 29 weeks' gestation) was associated with an increased risk of high blood pressure/hypertension/gestational hypertension, however the strength and statistical significance of low temperature effects were reduced with model adjustments. Our findings support the hypothesis that high temperatures in early pregnancy increase risk of severe hypertensive disorders, likely through an effect on placental development. This highlights the need for greater awareness around the impacts of moderately high temperatures in early pregnancy through targeted advice, and for increased monitoring of pregnant women who conceive during periods of hot weather.

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

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.

The Changing Climate and Pregnancy Health

PURPOSE OF REVIEW

Climate change is the biggest public health threat of the twenty-first century but its impact on the perinatal period has only recently received attention. This review summarizes recent literature regarding the impacts of climate change and related environmental disasters on pregnancy health and provides recommendations to inform future adaptation and mitigation efforts.

RECENT FINDINGS

Accumulating evidence suggests that the changing climate affects pregnancy health directly via discrete environmental disasters (i.e., wildfire, extreme heat, hurricane, flood, and drought), and indirectly through changes in the natural and social environment. Although studies vary greatly in design, analytic methods, and assessment strategies, they generally converge to suggest that climate-related disasters are associated with increased risk of gestational complication, pregnancy loss, restricted fetal growth, low birthweight, preterm birth, and selected delivery/newborn complications. Window(s) of exposure with the highest sensitivity are not clear, but both acute and chronic exposures appear important. Furthermore, socioeconomically disadvantaged populations may be more vulnerable. Policy, clinical, and research strategies for adaptation and mitigation should be continued, strengthened, and expanded with cross-disciplinary efforts. Top priorities should include (a) reinforcing and expanding policies to further reduce emission, (b) increasing awareness and education resources for healthcare providers and the public, (c) facilitating access to quality population-based data in low-resource areas, and (d) research efforts to better understand mechanisms of effects, identify susceptible populations and windows of exposure, explore interactive impacts of multiple exposures, and develop novel methods to better quantify pregnancy health impacts.

Immunological Changes in Pregnancy and Prospects of Therapeutic Pla-Xosomes in Adverse Pregnancy Outcomes

Stringent balance of the immune system is a key regulatory factor in defining successful implantation, fetal development, and timely parturition. Interference in these primary regulatory mechanisms, either at adolescence or prenatal state led to adverse pregnancy outcomes. Fertility restoration with the help of injectable gonadotrophins/progesterone, ovulation-inducing drugs, immunomodulatory drugs (corticosteroids), and reproductive surgeries provides inadequate responses, which manifest its own side effects. The development of a potential diagnostic biomarker and an effectual treatment for adverse pregnancy outcomes is a prerequisite to maternal and child health. Parent cell originated bi-layered-intraluminal nano-vesicles (30-150 nm) also known as exosomes are detected in all types of bodily fluids like blood, saliva, breast milk, urine, etc. Exosomes being the most biological residual structures with the least cytotoxicity are loaded with cargo in the form of RNAs (miRNAs), proteins (cytokines), hormones (estrogen, progesterone, etc.), cDNAs, and metabolites making them chief molecules of cell-cell communication. Their keen involvement in the regulation of biological processes has portrayed them as the power shots of cues to understand the disease's pathophysiology and progression. Recent studies have demonstrated the role of immunexosomes (immunomodulating exosomes) in maintaining unwavering immune homeostasis between the mother and developing fetus for a healthy pregnancy. Moreover, the concentration and size of the exosomes are extensively studied in adverse pregnancies like preeclampsia, gestational diabetes mellitus (GDM), and preterm premature rupture of membrane (pPROMs) as an early diagnostic marker, thus giving in-depth information about their pathophysiology. Exosomes have also been engineered physically as well as genetically to enhance their encapsulation efficiency and specificity in therapy for cancer and adverse pregnancies. Successful bench to bedside discoveries and interventions in cancer has motivated developmental biologists to investigate the role of immunexosomes and their active components. Our review summarizes the pre-clinical studies for the use of these power-shots as therapeutic agents. We envisage that these studies will pave the path for the use of immunexosomes in clinical settings for reproductive problems that arise due to immune perturbance in homeostasis either at adolescence or prenatal state.

Building sustainable and resilient surgical systems: A narrative review of opportunities to integrate climate change into national surgical planning in the Western Pacific region

Five billion people lack access to surgical care worldwide; climate change is the biggest threat to human health in the 21st century. This review studies how climate change could be integrated into national surgical planning in the Western Pacific region. We searched databases (PubMed, Web of Science, and Global Health) for articles on climate change and surgical care. Findings were categorised using the modified World Health Organisation Health System Building Blocks Framework. 220 out of 2577 records were included. Infrastructure: Operating theatres are highly resource-intensive. Their carbon footprint could be reduced by maximising equipment longevity, improving energy efficiency, and renewable energy use. Service delivery Tele-medicine, outreaches, and avoiding desflurane could reduce emissions. Robust surgical systems are required to adapt to the increasing burden of surgically treated diseases, such as injuries from natural disasters. Finance: Climate change adaptation funds could be mobilised for surgical system strengthening. Information systems: Sustainability should be a key performance indicator for surgical systems. Workforce: Surgical providers could change clinical, institutional, and societal practices. Governance: Planning in surgical care and climate change should be aligned. Climate change mitigation is essential in the regional surgical care scale-up; surgical system strengthening is also necessary for adaptation to climate change.

A Non-Randomized Controlled Trial for Reducing Postpartum Depression in Low-Income Minority Women at Community-Based Women's Health Clinics

OBJECTIVE

To analyze an intervention that delivered tailored clinic staff training on postpartum depression (PPD) followed by awareness raising and social support aimed at lowering PPD among low-income Bedouin women in southern Israel.

METHODS

We conducted a non-randomized controlled trial at two women's health clinics. The study included 332 of the 384 eligible women recruited at baseline (intervention = 169, control = 163), who completed two face-to-face interviews, one at 26-38 weeks of pregnancy (Time 1) and one 2-4 months postpartum (Time 2). PPD was measured by the Edinburgh Postnatal Depression Scale (EPDS) and dichotomized using a ≥ 10 score cutoff. We calculated EPDS change (rate difference of dichotomous EPDS from Time 1 to Time 2) (no change, positive change, or negative change), and compared EPDS changes in a control clinic vs. an intervention clinic.

RESULTS

The intervention group showed a greater decrease in dichotomous EPDS ≥ 10 between times 1 and 2 (38.5% to 17.2%) than the control group (31.9% to 29.4%, PV = 0.008). Multinomial logistic regression showed that high PPD awareness significantly contributed to positive EPDS change in the intervention group (PV = 0.003) and high social support significantly protected against negative EPDS change in both groups, intervention (PV = 0.001) and control (PV = 0.003).

CONCLUSIONS

In low-income women, an intervention focusing on increasing PPD awareness and social support following staff training was associated with reduced EPDS and positive EPDS change following the intervention. Similar interventions should be implemented in women's clinics during pregnancy.

CLINICAL TRIAL REGISTRY

ClinicalTrials.gov NCT02862444.

Biomimetics provides lessons from nature for contemporary ways to improve human health

Homo sapiens is currently living in serious disharmony with the rest of the natural world. For our species to survive, and for our well-being, we must gather knowledge from multiple perspectives and actively engage in studies of planetary health. The enormous diversity of species, one of the most striking aspects of life on our planet, provides a source of solutions that have been developed through evolution by natural selection by animals living in extreme environments. The food system is central to finding solutions; our current global eating patterns have a negative impact on human health, driven climate change and loss of biodiversity. We propose that the use of solutions derived from nature, an approach termed biomimetics, could mitigate the effects of a changing climate on planetary health as well as human health. For example, activation of the transcription factor Nrf2 may play a role in protecting animals living in extreme environments, or animals exposed to heat stress, pollution and pesticides. In order to meet these challenges, we call for the creation of novel interdisciplinary planetary health research teams.

Differences in environmental factors contributing to preterm labor and PPROM - Population based study

BACKGROUND

Previous reports indicate an association between ambient temperature (Ta) and air pollution exposure during pregnancy and preterm birth (PTB). Nevertheless, information regarding the association between environmental factors and specific precursors of spontaneous preterm birth is lacking. We aimed to determine the association between Ta and air pollution during gestation and the precursors of spontaneous preterm parturition, i.e. preterm labor (PTL) and preterm prelabor rupture of membranes (PPROM).

METHODS

From 2003 to 2013 there were 84,476 deliveries of singleton gestation that comprised the study cohort. Exposure data during pregnancy included daily measurements of temperature and particulate matter <2.5 μm and <10 μm, PM_2.5 and PM₁₀, respectively. Deliveries were grouped into PPROM, PTL and non-spontaneous preterm and term deliveries. Exposure effect was tested in windows of a week and two days prior to admission for delivery and adjusted to gestational age and socio-economic status. Poisson regression models were used for analyses.

RESULTS

There is an association of environmental exposure with the precursors of spontaneous preterm parturition; PPROM was more sensitive to Ta fluctuations than PTL. This effect was modified by the ethnicity, Bedouin-Arabs were susceptible to elevated Ta, especially within the last day prior to admission with PPROM (Relative Risk (RR) =1.19 [95% CI, 1.03; 1.37]). Jews, on the other hand, were susceptible to ambient pollutants, two (RR=1.025 [1.010; 1.040]) and one (RR= 1.017 [1.002; 1.033]) days prior to spontaneous PTL with intact membranes resulting in preterm birth.

CONCLUSION

High temperature is an independent risk factor for PPROM among Bedouin-Arabs; ambient pollution is an independent risk factor for spontaneous PTL resulting in preterm birth. Thus, the precursors of spontaneous preterm parturition differ in their association with environmental factors.

Extreme temperature and out-of-hospital-cardiac-arrest. Nationwide study in a hot climate country

BACKGROUND

Out-of-hospital-cardiac arrest (OHCA) is frequently linked to environmental exposures. Climate change and global warming phenomenon have been found related to cardiovascular morbidity, however there is no agreement on their impact on OHCA occurrence. In this nationwide analysis, we aimed to assess the incidence of the OHCA events attended by emergency medical services (EMS), in relation to meteorological conditions: temperature, humidity, heat index and solar radiation.

METHODS

We analyzed all adult cases of OHCA in Israel attended by EMS during 2016-2017. In the case-crossover design, we compared ambient exposure within 72 h prior to the OHCA event with exposure prior to the four control times using conditional logistic regression in a lag-distributed non-linear model.

RESULTS

There were 12,401 OHCA cases (68.3% were pronounced dead-on-scene). The patients were on average 75.5 ± 16.2 years old and 55.8% of them were males. Exposure to 90th and 10th percentile of temperature adjusted to humidity were positively associated with the OHCA with borderline significance (Odds Ratio (OR) =1.20, 95%CI 0.97; 1.49 and OR 1.16, 95%CI 0.95; 1.41, respectively). Relative humidity below the 10th percentile was a risk factor for OHCA, independent of temperature, with borderline significance (OR = 1.16, 95%CI 0.96; 1.38). Analysis stratified by seasons revealed an adverse effect of exposure to 90th percentile of temperature when estimated in summer (OR = 3.34, 95%CI 1.90; 3.5.86) and exposure to temperatures below 10th percentile in winter (OR = 1.75, 95%CI 1.23; 2.49). Low temperatures during a warm season and high temperatures during a cold season had a protective effect on OHCA. The heat index followed a similar pattern, where an adverse effect was demonstrated for extreme levels of exposure.

CONCLUSIONS

Evolving climate conditions characterized by excessive heat and low humidity represent risk factors for OHCA. As these conditions are easily avoided, by air conditioning and behavioral restrictions, necessary prevention measures are warranted.