Introduction
Climate-related exposures that can affect pregnancy
How heat, pollution, and stress influence pregnancy biology
Evidence on climate change effects on pregnancy
Pregnancy and newborn outcomes affected by climate stress
Mitigation and adaptation strategies
Research gaps and future directions
Conclusions
References
Further reading
As rising temperatures and environmental disruptions intensify, emerging evidence shows how climate change is reshaping pregnancy outcomes and newborn health worldwide.
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Introduction
This article examines the biological mechanisms and scientific evidence on how climate change-related exposure affects maternal complications, fetal development, and newborn health. Climate change is increasingly recognized as a major global health threat, with pregnant women identified as a particularly vulnerable population due to physiological adaptations affecting thermoregulation, cardiovascular function, endocrine balance, and immune responses.1,2
Pregnancy is a period of increased thermal stress due to its effects on heart function, metabolic rate, and thermal regulation, as well as reduced heat dissipation from the body. High heat exposure has been linked with adverse maternal and fetal outcomes.1,2 Physiological changes such as increased cardiac output, plasma volume, fetal metabolic heat production, and altered thermoregulation further increase susceptibility to heat stress, particularly in late pregnancy.2
Atmospheric emissions of fine particulate matter (PM2.5), ozone, and nitrogen dioxide are generated by urban sources, the use of fossil fuels, and wildfires, and the primary sources of these pollutants are traffic, factories, and wood-burning stoves. Airborne pollutants can deeply penetrate into the lungs to reach the bloodstream, where they have the potential to disrupt maternal-placental blood flow and alter fetal development.2 These exposures are also associated with systemic inflammation, oxidative stress, endothelial dysfunction, and altered vascular regulation, all of which can impair placental function.1,3
Extreme weather events such as floods, hurricanes, droughts, and wildfire smoke episodes can disrupt food systems, healthcare services, and living conditions. These disruptions may increase stress, limit access to prenatal care, and worsen nutritional stability during pregnancy.1 They may also trigger cascading indirect effects such as displacement, food and water insecurity, and increased exposure to infectious diseases.1 Climate-related risks are often unevenly distributed, disproportionately affecting populations with fewer socioeconomic resources.1,2
How heat, pollution, and stress influence pregnancy biology
During pregnancy, temperature regulation is disrupted by increased heat production and cardiac function. As a result, exposure to high temperatures increases the risk of dehydration, altered blood circulation, and reduced uterine blood flow, which can affect nutrient and oxygen delivery to the fetus.1,2 Heat stress may also activate the hypothalamic–pituitary–adrenal (HPA) axis and is associated with neuroinflammation and oxidative stress in the hypothalamus, potentially disrupting hormonal regulation.3
Environmental pollutants can also trigger inflammation, oxidative stress, and hormonal disturbances. Endocrine-disrupting chemicals, for example, may cross the placenta to influence immune responses and endocrine regulation within the maternal-fetal environment. 1,3 Heat and environmental stressors may further alter endocrine signaling (e.g., cortisol, ACTH) and interfere with the balance between hormonal and immune pathways required for maternal–fetal tolerance.3
Air pollutants, such as fine particulate matter, can enter the lungs and reach the bloodstream, potentially affecting placental circulation and fetal oxygenation. Climate-related disasters and environmental instability further increase psychological stress, which alters cortisol levels and may disrupt normal fetal growth and development.1 These combined exposures may reduce uterine blood flow, impair placental oxygen exchange, and shift fetal metabolism toward stress-adaptive (catabolic) pathways.1,3
Evidence on climate change effects on pregnancy
Several epidemiological studies indicate that high temperatures are associated with a greater risk of preterm births, low birthweight, and, in some cases, early term stillbirths. Data from large cohort studies across multiple regions agree that heat exposure in late pregnancy is associated with high rates of preterm birth or restriction of fetal growth; however, findings vary depending on exposure timing, geographic context, and study design, and some studies report null or mixed associations.1,2
A large meta-analysis found that each 1°C increase in temperature is associated with approximately a 4% increase in the risk of preterm birth, while heatwaves increase the odds by about 26%, although effect sizes vary across populations and exposure definitions.2
Air pollution has been widely investigated in relation to pregnancy outcomes, with PM2.5, ozone, and nitrogen dioxide exposure increasing the risk of preterm labor and reduced fetal growth rate, thus demonstrating that these airborne pollutants affect placental function and maternal cardiovascular response.1 Environmental chemicals released through pollution can also act as endocrine disruptors by interfering with hormonal signaling pathways and metabolic processes that regulate pregnancy, with emerging evidence linking these exposure events to altered fetal development and pregnancy complications.3 Heat exposure has also been associated with increased risks of gestational diabetes, hypertensive disorders, congenital anomalies, and stillbirth, although heterogeneity exists across studies and outcomes.2
Evidence suggests that multiple windows of susceptibility may exist, including preconception, early pregnancy, and late gestation, with both acute (short-term) and chronic (long-term) exposures contributing to risk.1,2
Pregnancy and newborn outcomes affected by climate stress
Extreme exposure to heat during pregnancy is associated with a greater likelihood of preterm delivery due to greater inflammation and disrupted hormonal signaling.1,2 Low birth weight and fetal growth restriction have also been associated with climate-related exposures. However, some outcomes such as low birth weight show inconsistent findings across studies, reflecting differences in exposure assessment and population characteristics.2
Meta-analyses show increased odds of congenital anomalies, stillbirth, and neonatal morbidity with higher heat exposure, alongside increased risks of preterm birth and reduced gestational duration.2
Heat stress and air pollution have the potential to impair placental function, reduce uterine blood flow, and limit oxygen and nutrient transfer to the fetus.1 Exposure to high temperatures may also influence hypertensive disorders of pregnancy, including preeclampsia, through effects on vascular regulation and endocrine responses.2 Vulnerability is often greater among populations with limited resources, reduced access to cooling or healthcare, and higher environmental exposures.1,3 Heat exposure has also been linked to increased maternal hospital admissions, infections, and obstetric complications, reflecting broader systemic impacts on maternal health.2
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Mitigation and adaptation strategies
Guidance from public health advocates includes simple actions such as staying hydrated, using shade or air-conditioned spaces for cooling, and modifying work or hobbies when the temperature is excessively high. Adopting measures to reduce pollutant exposure, such as improving indoor air quality and limiting exposure during periods of poor air quality, may further protect maternal health.1
Broader strategies involve strengthening community and health systems to respond to climate-related challenges. Health systems can also adapt by integrating climate awareness into prenatal care, improving surveillance of environmental exposures, and supporting vulnerable populations during extreme environmental events. Policy-level interventions, including emissions reduction, climate-resilient infrastructure, and targeted protection of high-risk populations, are critical to mitigating long-term risks.1
Research gaps and future directions
Most data on the relationship between climate change and pregnancy have come from short-term, small-scale studies, which limit the ability to understand long-term health effects and differences. A significant proportion of these studies have been conducted in high-income countries, which limits the generalizability of these findings to low- and middle-income regions where climate vulnerability may be greater.1,2 Recent large-scale reviews highlight substantial heterogeneity in study design, exposure metrics, and outcome definitions, complicating direct comparisons across studies.2
Measuring environmental exposure presents another challenge, as there are many differences in how researchers measure temperature, monitor pollution, and classify extreme weather events, making it difficult to compare their results. Thus, developing standardized exposure measurements and improved monitoring systems is indicated to improve future research.2
Longitudinal and mechanistic studies are also needed to clarify the biological pathways linking climate stressors with pregnancy complications. Emerging areas of interest include the role of environmental chemicals and endocrine-disrupting exposures in maternal metabolism, placental function, and fetal development.1 Future research should also focus on identifying critical windows of vulnerability and understanding combined or interacting exposures (e.g., heat and air pollution).2
Conclusions
Environmental changes related to climate, such as warmer global temperatures, air pollution, and extreme weather conditions, may affect the health of pregnant women and their unborn babies through biological and social pathways. Health care providers, communities, and policymakers must work collaboratively to improve surveillance of adverse outcomes and develop climate-adapted health delivery strategies. Given the increasing frequency and intensity of climate-related exposures and their complex, multi-system effects, protecting maternal and neonatal health should be a central priority in climate and public health policy.2
References
- Ha, S. (2022). The Changing Climate and Pregnancy Health. Current Environmental Health Reports 9; 263-275. DOI: 10.1007/s40572-022-00345-9. https://link.springer.com/article/10.1007/s40572-022-00345-9
- Lakhoo, D. P., Brink, N., Radebe, L., et al. (2025). A systematic review and meta-analysis of heat exposure impacts on maternal, fetal, and neonatal health. Nature Medicine 31(2); 684-694. DOI: 10.1038/s41591-024-03395-8. https://www.nature.com/articles/s41591-024-03395-8
- Yüzen, D., Graf, I., Diemert, A., & Arck, P. C. (2023). Climate change and pregnancy complications: From hormones to the immune response. Frontiers in Endocrinology 14. DOI: 10.3389/fendo.2023.1149284. https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2023.1149284/full
Further Reading
Last Updated: Mar 22, 2026