Increasing global temperatures threaten gains in maternal and newborn health in Africa: A review of impacts and an adaptation framework

Baicalin ameliorates heat stress-induced hepatic injury and intestinal microecology dysbiosis in late gestational mice

Heat stress (HS) disrupts intestinal microbiota, glycolipid metabolism, and hepatic mitochondrial function in late gestational mice. Baicalin (BAI), a Chinese herbal medicine known for its heat-clearing and anti-inflammatory properties, has shown promise in modulating intestinal microecology and mitigating inflammation in various organs. This study investigates whether baicalin attenuates HS-induced intestinal microbial dysbiosis and liver damage in pregnant mice during late gestation. Twenty-four pregnant mice were randomly assigned to four groups, including thermoneutral (TN) (24 ± 1 ℃), HS (35 ± 1 ℃), HS+BAI200 (oral gavaged with 200 mg/kg BW of BAI), and HS+BAI400 (oral gavaged with 400 mg/kg BW of BAI). 400 mg/kg BAI treatment markedly decreased the rectal temperature and increased fetal weight in HS pregnant mice. Furthermore, 400 mg/kg BAI administration effectively ameliorated HS-induced hepatic damage and lipid disorders, reducing HSP70, AST, and ALT levels while increasing TG concentration. Notably, it activated a network of genes involved in lipid synthesis, including fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC), and oxidation, such as peroxisome proliferator-activated receptor alpha (PPARα), carnitine palmityl transferase 1 beta (CPT1β). Moreover, BAI intervention restored the intestinal morphology and barrier function, evidenced by increased intestinal villus height, the ratio of villus height to crypt depth, and colonic goblet cells numbers. 400 mg/kg of BAI treatment up-regulated the expression of tight junction proteins, such as claudin-1 and Zonula Occludens-1 (ZO-1), in the jejunum and ileum, counteracting HS-induced downregulation. High-throughput sequencing showed that BAI treatment altered cecal microbial composition, increasing the relative abundance of beneficial Bacteroidota and decreasing Deferribacterota, Turicibacter, and Akkermansia. Spearman's correlation analysis highlighted significant correlations between differential cecal microbiota and physiological indexes. In conclusion, BAI administration alleviated adverse impacts in heat-exposed mice during late gestation, improving maternal physiological parameters, and ameliorating hepatic damage with altered cecal microbial composition. The findings suggest that BAI may regulate the gut-liver axis by modulating intestinal morphology, microecology, and hepatic function.

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.

Heat exposure induced risks of preterm birth mediated by maternal hypertension

Heat exposure is associated with an increased risk of preterm birth (PTB), with previous work suggesting that maternal blood pressure may play a role in these associations. Here we conducted a cohort study of 197,080 singleton live births across 8 provinces in China from 2015 to 2018. The study first estimated the associations between heat exposure, maternal hypertension and clinical subtypes of PTB, and then quantified the role of maternal hypertension in heat and PTB using mediation analyses. We show that heat exposure (>85th, 90th and 95th percentiles of local temperature distributions) spanning from conception to the 20th gestational week was associated with a 15-21% increase in PTB, and a 20-22% increase in medically indicated PTB. Heat exposure is likely to increase the risk of maternal hypertension and elevated blood pressure. Maternal hypertension mediated 15.7% and 33.9% of the effects of heat exposure (>90th percentile) on PTB and medically indicated PTB, respectively. Based on this large-population study, we found that exposure to heat in early pregnancy can increase the risk of maternal hypertension, thereby affecting the incidence of PTB.

Increased risk of preterm birth due to heat exposure during pregnancy: Exploring the mechanism of fetal physiology

BACKGROUND

Heat exposure during pregnancy can increase the risk of preterm birth (PTB) through a range of potential mechanisms including pregnancy complications, hormone secretion and infections. However, current research mainly focuses on the effect of heat exposure on pathophysiological pathways of pregnant women, but ignore that maternal heat exposure can also cause physiological changes to the fetus, which will affect the risk of PTB.

OBJECTIVE

In this study, we aimed to explore the mediating role of fetal heart rate (FHR) in the relationship between maternal heat exposure and PTB incidence.

METHODS

We assigned heat exposure to a multi-center birth cohort in China during 2015-2018, which included all 162,407 singleton live births with several times FHR measurements during the second and third trimesters. We examined the associations between heat exposure, FHR and PTB in the entire pregnancy, each trimester and the last gestational month. The inverse odds ratio-weighted approach applied to the Cox regression was used to identify the mediation effect of heat exposure on PTB and its clinical subtypes via FHR.

FINDINGS

Exposure to heat significantly increased the risk of PTB during the third trimester and the entire pregnancy, hazard ratios and 95 % CIs were 1.266 (1.161, 1.379) and 1.328 (1.218, 1.447). Heat exposure during the third trimester and entire pregnancy increased FHR in the third trimester by 0.24 bpm and 0.14 bpm. The proportion of heat exposure mediated by FHR elevation on PTB and its subtype ranged from 3.68 % to 24.06 %, with the significant mediation effect found for both medically indicated PTB and spontaneous PTB.

CONCLUSIONS

This study suggests that heat exposure during pregnancy has an important impact on fetal health, and FHR, as a surrogate marker of fetal physiology, may mediate the increased risk of PTB caused by extreme heat. Monitoring and managing physiological changes in the fetus would constitute a promising avenue to reduce adverse birth outcomes associated with maternal heat exposure.

High ambient temperature may increase the risk of anemia in pregnancy: Identifying susceptible exposure windows

Anemia in pregnancy (AIP) is associated with multiple severe maternal and perinatal adverse outcomes. However, there is a lack of evidence on the association between environmental factors and AIP. Aim to explore the association between ambient temperature and the risk of AIP, and identify susceptible exposure windows, we conducted a matched case-control study from 2013 to 2016 in Xi'an, China, which included 710 women with AIP and 1420 women without AIP. The conditional logistic regression model was used to evaluate the association between ambient temperature and AIP at different gestational weeks and gestational months. The association between extreme temperature and AIP was evaluated using the distributed lag nonlinear model (DLNM). We conducted stratified analyses of age, parity, and season of conception, and estimated the interaction between ambient temperature and air pollutants on AIP. Ambient temperature was significantly positively associated with the risk of AIP, and the susceptible exposure windows were 2-25 gestational weeks and 1-6 gestational months, respectively. The strongest effect was observed in the week 8 and month 2, for each 1 °C increase in weekly and monthly mean temperature, the odds ratio (OR) for AIP was 1.038 (95 % confidence interval (CI): 1.022, 1.055) and 1.040 (95 % CI: 1.020, 1.060), respectively. Extreme heat may increase the risk of AIP. Stratified analyses showed that there was no significant difference among different age, parity, and season of conception groups. No significant interaction effect of ambient temperature with air pollution on AIP was found. In summary, high ambient temperature may increase the risk of AIP, and the first and second trimesters may be susceptible exposure windows. Understanding the effect of temperature on pregnant women will be beneficial to reduce the occurrence of AIP.

Advancing disability-inclusive climate research and action, climate justice, and climate-resilient development

Globally, more than 1 billion people with disabilities are disproportionately and differentially at risk from the climate crisis. Yet there is a notable absence of climate policy, programming, and research at the intersection of disability and climate change. Advancing climate justice urgently requires accelerated disability-inclusive climate action. We present pivotal research recommendations and guidance to advance disability-inclusive climate research and responses identified by a global interdisciplinary group of experts in disability, climate change, sustainable development, public health, environmental justice, humanitarianism, gender, Indigeneity, mental health, law, and planetary health. Climate-resilient development is a framework for enabling universal sustainable development. Advancing inclusive climate-resilient development requires a disability human rights approach that deepens understanding of how societal choices and actions-characterised by meaningful participation, inclusion, knowledge diversity in decision making, and co-design by and with people with disabilities and their representative organisations-build collective climate resilience benefiting disability communities and society at large while advancing planetary health.

Extreme heat, pregnancy and women's well-being in Burkina Faso: an ethnographical study

Climate change is an increasing threat to the health of populations in Africa, with a shift in seasonal temperatures towards more extreme heat exposures. In Burkina Faso, like other countries in the Sahel, many women have little protection against exposure to high temperatures, either outside or inside the home or place of work. This paper investigates how women perceive the impacts of heat on their physical and mental health, in addition to their social relationships and economic activities. Qualitative methods (in-depth interviews and focus group discussions) were conducted with women, community representatives and healthcare professionals in two regions in Burkina Faso. A thematic analysis was used to explore the realities of participants' experiences and contextual perspectives in relation to heat. Our research shows extreme temperatures have a multifaceted impact on pregnant women, mothers and newborns. Extreme heat affects women's functionality and well-being. Heat undermines a woman's ability to care for themselves and their child and interferes negatively with breast feeding. Heat negatively affects their ability to work and to maintain harmonious relationships with their partners and families. Cultural practices such as a taboo on taking the baby outside before the 40th day may exacerbate some of the negative consequences of heat. Most women do not recognise heat stress symptoms and lack awareness of heat risks to health. There is a need to develop public health messages to reduce the impacts of heat on health in Burkina Faso. Programmes and policies are needed to strengthen the ability of health professionals to communicate with women about best practices in heat risk management.

Protocol of an individual participant data meta-analysis to quantify the impact of high ambient temperatures on maternal and child health in Africa (HE2AT IPD)

INTRODUCTION

Globally, recognition is growing of the harmful impacts of high ambient temperatures (heat) on health in pregnant women and children. There remain, however, major evidence gaps on the extent to which heat increases the risks for adverse health outcomes, and how this varies between settings. Evidence gaps are especially large in Africa. We will conduct an individual participant data (IPD) meta-analysis to quantify the impacts of heat on maternal and child health in sub-Saharan Africa. A detailed understanding and quantification of linkages between heat, and maternal and child health is essential for developing solutions to this critical research and policy area.

METHODS AND ANALYSIS

We will use IPD from existing, large, longitudinal trial and cohort studies, on pregnant women and children from sub-Saharan Africa. We will systematically identify eligible studies through a mapping review, searching data repositories, and suggestions from experts. IPD will be acquired from data repositories, or through collaboration with data providers. Existing satellite imagery, climate reanalysis data, and station-based weather observations will be used to quantify weather and environmental exposures. IPD will be recoded and harmonised before being linked with climate, environmental, and socioeconomic data by location and time. Adopting a one-stage and two-stage meta-analysis method, analytical models such as time-to-event analysis, generalised additive models, and machine learning approaches will be employed to quantify associations between exposure to heat and adverse maternal and child health outcomes.

ETHICS AND DISSEMINATION

The study has been approved by ethics committees. There is minimal risk to study participants. Participant privacy is protected through the anonymisation of data for analysis, secure data transfer and restricted access. Findings will be disseminated through conferences, journal publications, related policy and research fora, and data may be shared in accordance with data sharing policies of the National Institutes of Health.

PROSPERO REGISTRATION NUMBER

CRD42022346068.

Understanding the connections between climate change, air pollution, and human health in Africa: Insights from a literature review

Climate change and air pollution are two interconnected global challenges that have profound impacts on human health. In Africa, a continent known for its rich biodiversity and diverse ecosystems, the adverse effects of climate change and air pollution are particularly concerning. This review study examines the implications of air pollution and climate change for human health and well-being in Africa. It explores the intersection of these two factors and their impact on various health outcomes, including cardiovascular disease, respiratory disorders, mental health, and vulnerable populations such as children and the elderly. The study highlights the disproportionate effects of air pollution on vulnerable groups and emphasizes the need for targeted interventions and policies to protect their health. Furthermore, it discusses the role of climate change in exacerbating air pollution and the potential long-term consequences for public health in Africa. The review also addresses the importance of considering temperature and precipitation changes as modifiers of the health effects of air pollution. By synthesizing existing research, this study aims to shed light on complex relationships and highlight the key findings, knowledge gaps, and potential solutions for mitigating the impacts of climate change and air pollution on human health in the region. The insights gained from this review can inform evidence-based policies and interventions to mitigate the adverse effects on human health and promote sustainable development in Africa.

Multilevel interventions as climate change adaptation response to protect maternal and child health: a scoping review protocol

INTRODUCTION

Growing evidence suggests that climate change-related extreme weather events adversely impact maternal and child health (MCH) outcomes, which requires effective, sustainable and culturally appropriate interventions at individual, community and policy levels to minimise these impacts. This scoping review proposes to map the evidence available on the type, characteristics and outcomes of multilevel interventions implemented as adaptational strategies to protect MCH from the possible adverse effects of climate change.

METHODS

The following databases will be searched: Embase, MEDLINE, Emcare, EPPI-Centre database of health promotion research (BiblioMap) EPPI-Centre Database for promoting Health Effectiveness Reviews (DoPHER), Global Health, CINAHL, Joanna Briggs Institute EBP Database, Maternity and Infant Care Database, Education Resource Information Center, PsycINFO, Scopus, Web of Science and Global Index Medicus, which indexes Latin America and the Caribbean, Index Medicus for the South-East Asia Region, African Index Medicus, Western Pacific Region Index Medicus. Cochrane Central Register of Controlled Trials, WHO International Clinical Trials Registry Platform, ClinicalTrials.gov, conference proceedings, thesis and dissertations, policy and guidelines and their reference lists will also be searched. Two reviewers will independently screen titles and abstracts and full text based on predefined eligibility criteria. The Preferred Reporting Items for Systematic Reviews and Meta-analyses Extension for Scoping Reviews using the Population, Concept and Context framework and the Template for Intervention Description and Replication checklist will be used to structure and report the findings.

ETHICS AND DISSEMINATION

Ethics permission to conduct the scoping review is not required as the information collected is publicly available through databases. Findings will be disseminated through a peer-reviewed publication and conference presentations.

Extreme temperature increases the risk of stillbirth in the third trimester of pregnancy

Epidemiological studies have reported the association between extreme temperatures and adverse reproductive effects. However, the susceptible period of exposure during pregnancy remains unclear. This study aimed to assess the impact of extreme temperature on the stillbirth rate. We performed a time-series analysis to explore the associations between temperature and stillbirth with a distributed lag nonlinear model. A total of 22,769 stillbirths in Taiwan between 2009 and 2018 were enrolled. The mean stillbirth rate was 11.3 ± 1.4 per 1000 births. The relative risk of stillbirth due to exposure to extreme heat temperature (> 29 °C) was 1.18 (95% CI 1.11, 1.25). Pregnant women in the third trimester were most susceptible to the effects of extreme cold and heat temperatures. At lag of 0-3 months, the cumulative relative risk (CRR) of stillbirth for exposure to extreme heat temperature (29.8 °C, 97.5th percentile of temperature) relative to the optimal temperature (21 °C) was 2.49 (95% CI: 1.24, 5.03), and the CRR of stillbirth for exposure to extreme low temperature (16.5 °C, 1st percentile) was 1.29 (95% CI: 0.93, 1.80). The stillbirth rate in Taiwan is on the rise. Our findings inform public health interventions to manage the health impacts of climate change.