Study links prolonged heat exposure during pregnancy to adverse birth outcomes
First-trimester heat extremes were most critical for preterm birth, second trimester for low birth weight, and third trimester showed a higher risk for stillbirth, the study says
A recent study has uncovered a significant correlation between extended periods of extreme heat exposure during pregnancy and adverse birth outcomes in India. The research, titled 'Effect of extreme heat stress on adverse pregnancy outcomes in India', examined 209,266 births recorded between 2015 and 2020, comparing them to local heat conditions recorded during the same time frames.
This analysis, based on National Family Health Survey (NFHS) data, accounted for factors such as trimester-specific heat exposure windows, maternal BMI, education levels, and wealth groups.
The study revealed that exposure to extreme heat during the first trimester was most strongly linked to preterm births, while the second trimester saw an increased risk of low birth weight. Notably, the third trimester exhibited a higher risk of stillbirths. The findings also indicated that mothers with lower body mass indices (BMI), lower educational attainment, and those from poorer socioeconomic backgrounds were more susceptible to these adverse outcomes.
Additionally, urban residents experienced slightly higher rates of low birth weight compared to their rural counterparts.
The findings represent the first population-scale evidence in India linking prolonged extreme heat exposure (beyond just temperature) to negative pregnancy outcomes. The researchers utilized a heat index that incorporates various climatic factors such as humidity, wind, and radiation. This study highlights the potential biological mechanisms behind heat exposure, including increased maternal core body temperature, dehydration leading to uterine blood flow reduction and foetal growth impairment, and heightened risk of uterine contractions resulting in preterm births.
The study emphasizes the urgent need for India to prepare for the increasing heat challenges due to global warming, particularly in protecting marginalised populations, such as those with lower education levels and residing in rural areas, from these heat-related risks.
Written by urgent.news from The Hindu Health's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
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