Researchers published the study in Science Advances. They studied prenatal exposure to extreme heat and humidity in South Asia. To measure heat stress they used a combined metric called wet-bulb globe temperature (WBGT).
Humidity slows sweat evaporation and makes it harder for the body to cool. The team linked child health records with daily weather data and tracked four factors that affect heat stress: air temperature, humidity, radiant heat, and airflow.
They found that when humidity was included, the harm to child growth was much larger—about four times worse for exposure in the third trimester. The study notes limits, such as missing exact birth dates and pregnancy lengths.
Difficult words
- prenatal — happening before a baby is born
- exposure — contact with something, such as weather
- humidity — amount of water in the air
- wet-bulb globe temperature — a combined measure of heat and humidity
- airflow — movement of air in a place
- trimester — one of three pregnancy periodsthird trimester
- link — connect one thing or person to anotherlinked
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- How could very hot and humid weather during pregnancy affect a child?
- What can pregnant women do to stay cool in hot, humid weather?
- Have you experienced very hot and humid weather? How did it feel and what did you do?
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