Rising global temperatures threaten maternal and neonatal health outcomes, with vulnerable populations bearing the heaviest consequences. This comprehensive analysis reveals how extreme heat exposure during pregnancy significantly elevates the risk of delivering underweight infants, particularly affecting economically disadvantaged communities across South Asia.
Analyzing data from 85,017 births across Pakistan between 2008-2017, researchers found that maternal heat exposure increased low birth weight risk by up to 47% in certain provinces. The study employed sophisticated distributed-lag models to capture delayed temperature effects on fetal development, revealing province-specific vulnerability patterns. Nearly 19% of infants in the cohort were classified as low birth weight, with heat exposure contributing measurably to this burden. The research incorporated maternal education levels, household wealth indicators, urban-rural residence patterns, and air quality measurements to identify the most at-risk populations.
This investigation represents one of the most comprehensive climate-health analyses conducted in a low-middle-income country experiencing rapid warming. The findings align with emerging evidence that maternal heat stress disrupts placental function and fetal growth trajectories. Unlike previous smaller studies, this research provides district-level vulnerability mapping and future risk projections under different climate scenarios. The heat vulnerability index developed could guide targeted interventions for pregnant women in high-risk areas. However, the observational design cannot establish definitive causation, and the study lacks individual-level temperature exposure measurements. As global temperatures continue rising, these findings underscore the urgent need for climate-adapted maternal healthcare strategies, particularly in resource-constrained settings where cooling access remains limited.