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 new study, published in the academic journal, has found a correlation between prolonged exposure to extreme heat during pregnancy and adverse birth outcomes in India. Utilizing data from the National Family Health Survey (NFHS), researchers analyzed 209,266 births between 2015 and 2020, matched with local heat conditions during pregnancy. The paper, titled 'Effect of extreme heat stress on adverse pregnancy outcomes in India', explored the impact of heat exposure on the trimester in which it occurred.
The researchers, Vineetha Vincent and her team, discovered that heat extremes during the first trimester were most strongly associated with preterm birth, while exposure during the second trimester correlated with low birth weight, and the third trimester was tied to a higher risk of stillbirth. The authors noted that these risks were higher for mothers with low Body Mass Index (<18.5), lower educational attainment, and belonging to poorer wealth groups.
Furthermore, the study found that urban residents experienced slightly higher rates of low birth weight in comparison to their rural counterparts. The findings also showed that mountainous zones exhibited stronger associations between heat exposure and pregnancy outcomes, while humid subtropical and arid zones demonstrated significant low birth weight occurrences.
This research marks the first population-scale evidence from India establishing a link between prolonged extreme heat stress and adverse pregnancy outcomes, utilizing a heat index that factors in humidity, wind, and radiation. The authors argue that this evidence highlights the potential biological effects of high ambient temperature, such as increased maternal core body temperature leading to birth defects, dehydration reducing uterine blood flow and foetal growth, and increased risk of uterine contractions and preterm birth.
Low and middle-income countries like India face higher birth rates, resulting in a larger absolute number of adverse birth outcomes. With climate change expected to exacerbate extreme conditions, the researchers suggest that India should prepare to address heat challenges through better adaptation planning. They emphasize the need to raise awareness about the risks of heat exposure for pregnant women from marginalized populations, particularly those with lower education levels and residing in rural areas.
Written by urgent.news from The Hindu's reporting — not their text. Machine-written — it may contain errors, so check the original before relying on it.
