Climate Change Threatens Healthy Pregnancies: How Rising Temperatures Impact Maternal and Fetal Health
The increasing number of extremely hot days resulting from climate change is impacting human health, with links to heatstroke, dehydration, and respiratory issues. Pregnant individuals face heightened risks of health complications due to these rising temperatures.
A study released on May 14 revealed that extreme heat caused by climate change poses significant threats to maternal health and birth outcomes. The average number of days with pregnancy heat-risk—defined as days where maximum temperatures exceed 95% of recorded temperatures in a given location—doubled in 222 countries between 2020 and 2024. The most significant increase in heat-risk days was observed in developing regions with limited healthcare access, including the Caribbean, parts of Central and South America, and sub-Saharan Africa.
Shruthi Mahalingaiah, an associate professor at the Harvard T.H. Chan School of Public Health, emphasizes that pregnant women and their fetuses are particularly vulnerable to climate-related changes, specifically heat. She explains that pregnant individuals may have difficulty regulating their body temperature compared to non-pregnant individuals, as their bodies are already working hard to support the fetus. This makes it harder to cool the fetal environment to a safe temperature.
Anna Bonell, assistant professor at the London School of Hygiene & Tropical Medicine, notes that extreme heat increases the risk of expectant mothers developing conditions like pre-eclampsia and gestational diabetes.
Mahalingaiah also points out the impact on fetal development, noting that fetuses lack the ability to regulate their own temperature and that fetal organ development is highly sensitive to temperature. Research suggests a link between exposure to extreme heat and an increased risk of birth defects, such as neural tube defects like spina bifida.
Bonell states that exposure to extreme heat is clearly linked to a higher risk of preterm birth, stillbirth, smaller babies, and congenital abnormalities. A 2024 study indicated that rates of preterm and early-term births rose when local temperatures remained abnormally high for more than four consecutive days. Preterm births can lead to long-term health problems for the child, increasing the risk of death, hospitalizations, and chronic illnesses, according to Bonell.
Extreme heat can also compromise the effectiveness of contraception and pregnancy tests, as these items are susceptible to damage from high temperatures. MSI Reproductive Choices reported that since 2011, approximately 11.5 million women in 26 countries have experienced disruptions in their access to contraception due to climate-related displacement.
Marginalized communities face the greatest health risks from climate change. Howie Wu, assistant professor at Columbia University, explains that lower-income populations with limited access to healthcare are inherently disadvantaged. Individuals without air conditioning or shade are more prone to heat-related complications, while those living near highways are more likely to be exposed to pollutants.
Other climate-related stressors have also been linked to pregnancy complications. Air pollution is associated with increased risks of high blood pressure during pregnancy, low birth weight, preterm birth, and adverse effects on fetal brain and lung development. A 2020 study indicated that severe storms, such as cyclones and hurricanes, can trigger early births due to increased stress, environmental contamination, and disruptions in healthcare services.
Disruptions in accessing care due to extreme weather can have widespread consequences. A 2023 report found that human-driven climate change has increased the risk of damage to hospitals by 41%. Experts highlight that these disruptions can create ripple effects. Wu notes that Hurricane Sandy in New York City impacted the availability of prenatal care, emphasizing the underappreciated and understudied consequences of extreme weather events on care providers.
Experts emphasize the need for further research to fully understand how climate change affects pregnancies and fetal development. Mahalingaiah stresses the importance of considering both the upstream and downstream effects on the reproductive life cycle of pregnant individuals and acknowledges that much more remains to be learned.
“`