21-05-2025
More hot days mean higher pregnancy risk, according to climate research
As average temperatures heat up across the world, it's posing a threat to global pregnancies. According to a report from Climate Central, nearly ever country on earth is seeing more days with extreme heat, linked with higher pregnancy risks.
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The study tracked the number of days between 2020 and 2024 a country, state or city experienced temperatures above the 95th percentile of the 30-year average temperatures.
For example, in Charlotte, 95% of the time we should expect temperatures to be below 94 degrees. During the years in this study, the researchers found the city hit those temperatures about 13 times a year, 11 more days than researchers would expect to find if the city wasn't experiencing a warming trend due to climate change.
The more of these warmer days we see, the riskier things can get for vulnerable populations like young children and expectant mothers.
Dr. Melissa Woolworth, an academic specialist at OB/Gyn at Atrium Health, explains that due to the increased blood flow women experience during pregnancy, they're more at risk for heat stress and dehydration.
'If mom's really overheated, the body's really going to divert blood flow to the skin to try and cool her off better, and that's going to affect blood flow to the placenta,' she said. 'When mom's not feeling well, we definitely see that baby is suffering from those effects as well.'
This can lead to pre-term labor, lower weights and in the worst cases, higher risks of a stillborn birth. According to Woolworth, the risk is highest in the third trimester, but prolonged exposure to heat poses a threat at every stage of pregnancy.
'There are some effects for first trimester moms, as well,' she said. 'We know there's an increased risk for miscarriage and congenital anomalies.'
The Climate Central Study looked at 247 countries in total, finding the highest increases in pregnancy heat risk days in the Caribbean, parts of Central and South America as well as the Pacific Islands, Southeast Asia and sub-Saharan Africa.
Across the United States, the study found on average pregnancy heat risk days doubled, but the worst increases were primarily concentrated in the Southwest.
To help pregnant patients cope with higher temperatures, Woolworth advises anyone expecting to limit their time outside, drink plenty of fluids and if they need to be outside to stick to shady areas.
She also advises medical providers to be aware of patients who may not have reliable access to air conditioning.
'A lot of our patients who are under resourced face these types of effects of dehydration and heat a little bit more profoundly,' she said. 'If they're feeling bad or their baby's not moving well, then definitely encourage them to seek medical attention.'
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