Impact of Extreme Ambient Heat on Pregnancy Outcomes in Pakistan: A Multi-Regional Age-Stratified Analysis Across Different Climatic Zones
1
Department of Life Sciences, Lahore University of Management Sciences, Lahore, Pakistan
Popul. Med. 2026;8(Supplement Supplement 1):
ABSTRACT
BACKGROUND:
Heat exposure during pregnancy is a growing concern in climate-vulnerable regions, yet little is known about its effects across different population and geographic contexts in South Asia.
METHODS:
This multi-regional cohort study investigates the relationship between ambient heat and pregnancy outcomes. The study was performed across four diverse Pakistani cities including Lahore, Karachi, Muzaffargarh, and Badin, spanning inland and coastal microclimates. We analysed 40,601 delivery records (2021–2024), incorporating daily environmental data (temperature, humidity, and heat index) using stratified logistic regression models to assess the effect of heat exposure during trimester-specific windows.
RESULTS:
Our findings indicate a significant increase in preterm birth risk, particularly during the third trimester under extreme heat conditions (OR = 1·82, p < 0·001). Age-stratified models reveal that older mothers are more susceptible to heat-induced preterm births than younger mothers. Additional analyses uncover associations of heat with lower birthweight, elevated caesarean rates, and prolonged hospital stays. Regional differences in outcomes underscore the importance of tailoring interventions to local climatic and socioeconomic contexts. Interpretation: These findings are first to provide robust evidence of heat-related maternal vulnerability in South Asia, highlighting the urgent need for climate-resilient public health policies. Funding: This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Heat exposure during pregnancy is a growing concern in climate-vulnerable regions, yet little is known about its effects across different population and geographic contexts in South Asia.
METHODS:
This multi-regional cohort study investigates the relationship between ambient heat and pregnancy outcomes. The study was performed across four diverse Pakistani cities including Lahore, Karachi, Muzaffargarh, and Badin, spanning inland and coastal microclimates. We analysed 40,601 delivery records (2021–2024), incorporating daily environmental data (temperature, humidity, and heat index) using stratified logistic regression models to assess the effect of heat exposure during trimester-specific windows.
RESULTS:
Our findings indicate a significant increase in preterm birth risk, particularly during the third trimester under extreme heat conditions (OR = 1·82, p < 0·001). Age-stratified models reveal that older mothers are more susceptible to heat-induced preterm births than younger mothers. Additional analyses uncover associations of heat with lower birthweight, elevated caesarean rates, and prolonged hospital stays. Regional differences in outcomes underscore the importance of tailoring interventions to local climatic and socioeconomic contexts. Interpretation: These findings are first to provide robust evidence of heat-related maternal vulnerability in South Asia, highlighting the urgent need for climate-resilient public health policies. Funding: This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
| eISSN: | 2654-1459 |
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