Extreme April heat linked to 10,050 preterm births in India

Extreme heat during April 2024 was associated with around 10,050 additional preterm births in India. The findings deepen concerns about climate change's impact on maternal and newborn health. India's increasingly punishing summers may be taking a toll even before babies are born. A new analysis has found that extreme heat, intensified by human-induced climate change, contributed to thousands of premature births in India during the exceptionally hot April of 2024, raising fresh concerns about the impact of global warming on maternal and newborn health.The analysis by Zero Carbon Analytics, which examined the impact of the April 2024 heat event across India, Bangladesh and the Philippines, estimates that the extreme temperatures were associated with around 16,150 additional preterm births across the three countries compared with what would have been expected in a typical April.India accounted for approximately 10,050 of these births.More significantly, the researchers estimate that around 10,600 premature births across the three countries would not have occurred without the additional warming caused by human-induced climate change. The findings offer another dimension to the growing health costs of global warming in South Asia, where extreme heat is becoming more frequent, prolonged and intense.And researchers studying the toll of climate change on health underline that the consequences can extend well beyond delivery. “Babies born prematurely are at greater risk of breathing difficulties, infections, developmental problems and long-term neurological complications. Preterm birth is also the leading cause of death among newborns globally and India,” said an epidemiologist with the Indian Council of Medical Research (ICMR).India already carries a substantial burden.Its preterm birth rate was estimated at 13% in 2020, among the highest in the world. The country accounted for around one-fifth of all premature births globally that year. Rising temperatures could add to an already significant maternal and newborn health challenge. HEAT’S TOLLThe analysis estimates that India's April 2024 heat event was associated with a 3.6% increase in preterm births compared with a typical April. The impact was uneven across the country, with Bihar, Uttar Pradesh, West Bengal and Jharkhand together accounting for around 65% of India's additional premature births.West Bengal and Bihar experienced some of the sharper increases in the risk of premature delivery, while Uttar Pradesh's large contribution was also driven by its substantial population.The researchers estimate that the average person in India experienced temperatures around 0.94 degrees Celsius above normal in April 2024. In some northeastern states, including Tripura and Mizoram, temperatures were approximately 2.7 degrees above the usual April average, translating into an estimated 11% increase in preterm birth risk.The researchers also project that the problem could become considerably worse. By the middle of this century, climate change could contribute to around 15,300 additional premature births in India in a typical April, assuming no adaptation measures are taken.A WIDER HEALTH CRISISThe findings come against the backdrop of India's rapidly changing temperature profile. The country has been experiencing hotter summers, longer heat spells and warmer nights, with climate change making extreme heat events more likely.The 2025 Lancet Countdown report on health and climate change found that, between 2016 and 2025, half of the heatwave days experienced in India were attributable to climate change. On average, people faced 10.6 heatwave days annually, of which 5.3 would not have occurred without human-induced warming.The health consequences extend well beyond heatstroke and dehydration. Prolonged heat exposure increases cardiovascular and kidney stress, aggravates existing illnesses, disrupts sleep and reduces people's ability to work.Changing temperatures and rainfall patterns also affect the spread of vector-borne infections such as dengue and malaria, while floods, droughts and declining food security can worsen malnutrition and disease vulnerability.Pregnancy adds another layer of vulnerability.“Heat can cause dehydration, increase cardiovascular strain and reduce blood flow to the placenta. Researchers believe these changes, along with inflammation and the activation of biological pathways associated with labour, may contribute to early delivery,” said the ICMR epidemiologist.A synthesis of global studies cited in the Zero Carbon Analytics analysis found that every 1-degree Celsius increase in heat exposure was associated with 4% higher odds of preterm birth. During heatwaves, the odds rose by 26%. - Ends