Archive · 21 Jul 2026
Extreme heat during pregnancy raises low birth weight risk
A big study in India found that when pregnant women are exposed to very hot weather for a long time, their babies are more likely to be born too small or too early.
This is especially true in very hot and dry areas like parts of Karnataka.
The study looked at over 200,000 births and found that each extra very hot day during pregnancy makes the risk a little bit higher.
Women who didn't finish school were at even more risk.
Experts say we need to protect pregnant women from the heat as the climate gets hotter.
Prolonged exposure to extreme heat during pregnancy increases the risk of low birth weight and preterm births.
Karnataka's semi-arid Deccan belt is one of the most vulnerable regions, accounting for nearly 30% of low-birth-weight births in India.
Every additional consecutive sweltering day during pregnancy increases the likelihood of low birth weight by around 1%.
Heat exposure during the first trimester is linked to preterm births, while exposure during the second trimester is associated with lower birth weight.
Women with little or no formal education face greater risks, highlighting the need for heat action plans to prioritize pregnant women.
- Who
- Pregnant women, particularly in semi-arid regions of India
- What
- Extreme heat during pregnancy increases the risk of low birth weight and preterm births
- When
- Between 2015 and 2020
- Where
- India, particularly Karnataka's semi-arid Deccan belt
- Why
- Due to prolonged exposure to extreme heat, which is exacerbated by climate change
Climate Change Impact
Public Health Measures
Impact of Extreme Heat
Climate Change Impact
Extreme heat during pregnancy significantly increases the risk of low birth weight and preterm births, particularly in semi-arid regions like Karnataka's Deccan belt.
Public Health Measures
Implementing heat action plans and prioritizing pregnant women in public health measures can mitigate these risks.
- Study Period
- 2015-2020
- Number of Births Analyzed
- 2.09 lakh
- Increase in Low Birth Weight Risk
- 1% per additional consecutive sweltering day
- Vulnerable Regions
- Karnataka's semi-arid Deccan belt (Kalaburagi, Raichur, Vijayapura)
- Journal
- Environmental Research Communications