Climate change-induced excessive heat poses a danger to pregnancies, according to research findings.
A new report by Climate Central has revealed that climate change is increasing the number of dangerous extreme heat days for pregnant women worldwide, with Asia being one of the most severely affected regions.
The study, published in 2025, found that in the United States, climate change has increased the frequency of pregnancy-heat-risk days by at least 48%, with many states experiencing one to two additional weeks of such high-risk days annually. Although specific data for Asia in the report is not explicitly detailed, experts emphasize that regions already facing extreme heat and adverse birth outcomes—many of which are in Asia—experience much greater health risks linked to rising temperatures.
Extreme heat exposure during pregnancy is associated with serious health complications, including increased risk of preeclampsia, gestational diabetes, preterm birth, stillbirth, low birth weight, and fetal stress. In Asia and similar hot climates, pregnant women are disproportionately exposed due to environmental, occupational, and socioeconomic factors, heightening their vulnerability.
Heat waves globally raise the odds of early birth by 16 to 26 percent and exacerbate other pregnancy complications. Studies from agricultural regions like The Gambia—an example relevant by analogy to some Asian contexts due to the rural female workforce exposure—show pregnant women regularly experiencing heat stress symptoms, indicating similar risks in comparable environments across Asia.
Climate change also disrupts access to prenatal care and clean water in many regions, compounding pregnancy health risks during periods of extreme heat or climate disasters.
According to a population study by The Lancet, three-quarters of countries will not have high enough fertility rates to sustain their population size by 2050, and 97 per cent of countries will have a similarly unsustainable fertility rate by the end of the century. The UN expects the world's population to peak at 10.3 billion by the mid-2080s, down from a previous anticipation due to a rapidly declining fertility rate in high and middle-income countries.
The hottest year on record was between 2020 and 2024, during which man-made climate change was responsible for at least one month's worth of pregnancy heat-risk days every year in one third of the territories studied. In Asia, one-fifth of analysed countries (11 out of 57) experienced at least one additional month of pregnancy heat-risk days on average each year due to climate change, with Southeast Asia the most heavily affected sub-region.
City-wise, Indonesia's Batam, which borders Singapore, was found to be the region's most dangerous for pregnant women, followed by neighbouring Singapore and Zamboanga in the Philippines. Brunei was the next most severely affected Asian territory, with 42 out of 44 pregnancy heat-risk days attributable to climate change, followed by Indonesia (41 out of 44 days) and Malaysia (35 out of 38 days).
A 2024 study by the Yong Loo Lin School of Medicine at the National University of Singapore found that climate-induced heat stress can lead to lower sperm count and concentration among men. Dahl noted that changes in fertility rates and population trends have many different causes, but stressed that the impacts on maternal and infant health are likely to worsen if insufficient action is taken to reduce fossil fuel consumption.
Other studies have shown that warmer temperatures can damage women's eggs, disrupt the ovulation cycle, and harm the development of the formed embryo. A study conducted in 18 African countries found that women exposed to abnormal environmental conditions were less willing to have children.
In summary, climate change expands the number of dangerous heat days for pregnant women worldwide, with Asia among the most heavily impacted regions where heat conditions and preexisting health vulnerabilities combine to increase pregnancy risks significantly. It is crucial to address the impacts of climate change on maternal and infant health, particularly in developing regions with relatively poor access to healthcare, such as Southeast Asia, Central and South America, and sub-Saharan Africa.
