Why Humidity Makes Heat More Dangerous for Pregnant Women
Summary: A study in South Asia finds that children exposed to hot and humid conditions have a shorter height on average and face health issues.
The study
A study carried out by the University of California, Santa Barbara, on the Indian subcontinent shows that the hot and humid climate prevents pregnant women from cooling down, which affects the health of their to-be-born children.
The method
The study looked at a height-for-age ratio, i.e., the ratio of a child’s height and compared it with the average height of their age. This ratio is a common parameter to gauge the chronic health status of children aged less than 5 years.
The Demographic and Health Surveys (DHS) is a comprehensive and large-scale household survey of public health and demographics. The data on child health from this survey was gathered, as well as the data on the daily weather conditions. This data was linked to gauge the prenatal heat exposure among the pregnant women. Thereafter, this data was passed through statistical models with temperature, humidity and growth parameters.
The parameters
The parameters were 35 °C (95o F) for temperature and 29 °C (84 o F) for wet bulb globe temperature (four factors affecting heat stress, including air temperature, humidity, radiant heat sources and airflow.
For comparison, two levels, i.e. heat and hot-humid, which occur frequently in South Asia, were referred to.
The finding
The finding shows that exposure to extreme heat was bad, but exposure to humidity was worse. For example, it was observed that exposure to heat and humidity during the third trimester was four times worse than exposure to heat alone.
It was also observed that, in the year before birth, a child exposed to a one-standard-deviation increase in heat and humidity would be 13% shorter for their age than is expected. In comparison, a child exposed to one standard deviation of extreme heat conditions would be 1% shorter for their age.
The fact is that some of the densely populated regions on Earth are hot, humid and found along rivers and coastlines. The population continues to grow in these regions.
Therefore, the impact of the weather conditions must be a point of focus, rather than just noting the effects of the temperature of the region. Another fact is that the present climatic conditions will lead to an increase in hot and humid conditions. It is also pointed out that more understanding regarding the effect of the increasing humidity on worsening the heat conditions is required.
The research paper – ‘Does humidity matter? Prenatal heat and child health in South Asia, authored by Kathryn McMahon, Kathy Baylis, Stuart Sweeney and Chris Funk, has been published in the journal Science Advances.
Conclusion
Prenatal heat is the extreme effect of heat and humidity on the developing fetus. It is detrimental to the fetus as it may lead to premature birth, low birth weight, birth defects or stillbirth, given the increased maternal core temperature and stress caused to the cardiovascular system of the pregnant woman. Rising humidity makes these pregnant women feel hotter due to increased blood volume and metabolism. Plus, the added weight of the fetus is like an insulation that slows down the cooling of the pregnant woman’s body.
Precautions to be taken by pregnant women are :
- Cool down: Use air conditioners in the bedroom and try not to move outdoors.
- Hydrate: Stay hydrated to prevent dehydration.
- Be cool: Soak hands, arms and feet in cool water to cool the body.
- Humidity check: Stay safe from humidity.
- Air quality: Monitor air quality as pollution elevates heat conditions.
Source: Inputs from various media Sources
- Health News and Updates,People Forum
- 13 January 2026
- 19:00
