A new report claims that climate change has adverse effects on pregnant mothers who are more likely to have premature, underweight or stillborn children. The research by JAMA Network Open, part of the Journal of the American Medical Association, provides evidence that exposure to air pollution and heat exacerbated by climate change may be significantly associated with risk to pregnancy outcomes in the United States.

The report looked at more than 32 million births across 57 studies published since 2007 and found a high likelihood that heat, ozone, or fine particulate matter impact pregnancy outcomes. It also found that African-American mothers and babies have a much higher chance of being affected than the population at large. This adds to the growing consensus that minorities and marginalised groups are disproportionately at higher risk of climate change effects.

The paper examined 10 studies that surveyed the association between heat exposure and outcomes such as preterm birth and low birth weight, with nine of the 10 articles finding a significant association between exposure to heat during pregnancy and such births. Studies also showed that maternal exposure to particulate matter (pollutants) and ozone increases the risk of such outcomes. Racial disparities were one of the key findings: 10 studies reported increased risk of preterm birth among mothers in minority groups, with 8 of the studies noting higher risk for Black mothers. Similar results were seen for low birth weight outcome. Mothers with asthma were at particularly high risk, along with Black mothers. Heat exposure was found to negatively impact births in multiple studies.

Rupa Basu, one of the paper’s authors and chief of the air and climate epidemiological section for the Office of Environmental Health Hazard Assessment in California, said that the racial disparities are likely due to several systemic problems such as Black and other minorities living closer to power plants and other sources of air pollution, less likely to afford air conditioning, having less access to healthcare, and not receiving equal levels of treatment.