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?
Related articles
Hurricane Melissa threatens Jamaica in late October
Hurricane Melissa moved across the central Caribbean in late October and strengthened. Officials issued warnings from October 20, shelters opened, power and water failed in places, and Jamaica recorded deaths and injuries before an expected landfall on October 28.
2025 aid cuts threaten health and humanitarian services
Large reductions in international aid in 2025 disrupted health and humanitarian services in many low- and middle-income countries. The cuts began with a US suspension of aid and led to the closure of USAID and wider global impacts.
Gut has a backup system for IgA antibodies
Researchers found two different routes that make IgA antibodies in the gut. Early IgA often comes from non‑germinal center cells but later from germinal centers; both types showed similar specificity and mutations, which may help vaccine design.
