Extreme heat raises low birth weight risks for newborns, study warns

A new study has linked extreme heat exposure to a higher risk of low birth weight in newborns. Published in BMC Medicine, the research analysed data from over 85,000 mother-infant pairs in Pakistan. Findings suggest that rising temperatures could worsen the problem in the coming decades. The study found that 18 percent of infants in the dataset had low birth weight. Of these cases, 13 percent were connected to above-average temperatures during pregnancy. Heat stress can disrupt maternal health by causing dehydration, poor placental function, and reduced blood flow to the uterus—all of which restrict fetal growth.

Regions like Southern Punjab, northern Sindh, and Baluchistan face the greatest risks. These areas combine high heat exposure with socioeconomic challenges, leading to a potential 70 percent increase in low birth weight cases. Researchers created a heat vulnerability index to help officials direct resources to the most affected communities.

By the 2060s, climate projections suggest an 8 to 10 percent rise in heat-related low birth weight risks globally. The study calls for more long-term research on how early heat exposure affects children's development and adult health. It also urges policymakers to adapt maternal and neonatal care programmes to address climate impacts. The findings highlight an urgent need for targeted interventions in high-risk regions. Health systems must now integrate climate data into prenatal care strategies. Without action, the study warns, more infants could face lifelong health consequences due to rising temperatures.