Preterm births in India: How climate change is driving early deliveries

An exceptionally hot April in 2024 was associated with an estimated 10,050 additional preterm births in India. But what was an unusual heat event could become an increasingly familiar public health challenge: by the middle of this century, climate change could drive more than 15,300 excess preterm births in the country during an ordinary April, according to a new analysis by international research group Zero Carbon Analytics (ZCA). Preterm births are defined as babies born alive before the completion of 37 weeks of pregnancy.Zero Carbon Analytics (ZCA) is an international research organisation that provides independent research, insights and analysis on climate change and the global energy transition.The projections suggest that an average April between 2041 and 2060 could carry a greater burden of heat-associated premature births than the exceptionally hot month of April 2024, when large parts of South and Southeast Asia experienced extreme temperatures. The researchers estimate that India's mid-century burden could be around 50% higher than that associated with the 2024 event.The findings highlight the growing risks that rising temperatures pose to pregnant women and newborns in India, where preterm birth is already a major public health concern. Preterm birth is the leading cause of neonatal mortality globally and can have long-term consequences for children's physical health, neurodevelopment and socioeconomic well-being, the study said.The ZCA analysis found that the April 2024 heat event was associated with a 3.6% increase in preterm births in India compared with what would normally be expected during April, based on the 1991–2020 climate baseline. The event was made at least 45 times more likely by human-caused climate change, according to the report.The estimated additional preterm births were not evenly distributed across the country. Bihar, Uttar Pradesh, West Bengal and Jharkhand together accounted for 65% of India's estimated excess preterm births during April 2024.India experienced temperatures averaging 0.94°C above normal during the month, but state-level differences were considerable. Tripura and Mizoram were around 2.7°C warmer than their respective April averages, corresponding to an estimated 11% increase in preterm birth risk in both states. West Bengal recorded an estimated 10% increase, while Bihar saw a 7% increase.Uttar Pradesh, despite experiencing a comparatively smaller temperature anomaly of 0.74°C, accounted for a substantial share of the additional births because of its large population. The report also found that Karnataka had the highest rate of excess preterm births, at 12 per 1,000 births, reflecting both a temperature anomaly of around 2°C and a higher-than-average baseline preterm birth rate.The analysis estimates that approximately 10,600 preterm births across India, Bangladesh and the Philippines would not have occurred during April 2024 without the additional warming caused by human-induced climate change. This is a separate estimate from the 16,150 excess preterm births associated with the entire heat event across the three countries.An ordinary April could become more dangerousTo assess how continued global warming could affect pregnancy outcomes, the researchers modelled future temperatures under two climate scenarios: SSP2-4.5, representing moderate emissions, and SSP3-7.0, a higher-emissions pathway.By mid-century, April temperatures in India are projected to be around 1.6°C higher than the 1985–2014 baseline. This could translate into approximately 15,300 excess preterm births during a typical April, with the estimated range extending from 6,800 to 28,100.Uttar Pradesh is projected to carry the largest absolute burden, followed by Bihar and Rajasthan. Under the moderate emissions scenario, Uttar Pradesh alone could see an estimated 4,376 excess preterm births in an average April between 2041 and 2060. Under the higher-emissions scenario, the estimate rises to 4,521.These projections account for declining fertility and changes in the number of births using the United Nations' World Population Prospects 2024. The researchers estimate that India's annual births by mid-century will be around 18% lower than in 2024.However, the projections assume that the relationship between temperature and preterm birth observed today will remain unchanged, with no physiological, behavioural or healthcare-system adaptation. They are modelled estimates rather than predictions of the exact number of premature births that will occur.The researchers also caution that some births counted as excess preterm births may have been brought forward by heat, even if they would have occurred prematurely a few days or weeks later. Their methodology cannot distinguish these births from those that would otherwise have reached full term.Heat is not the only climate-related threatExtreme heat is one of several environmental pressures affecting maternal and newborn health. The report also highlights evidence linking floods, changing rainfall patterns and air pollution to adverse pregnancy and childhood outcomes in India.Flood-affected regions have an 8% higher prevalence of low-birthweight infants and a 27% higher prevalence of very low-birthweight infants, according to studies cited in the report. Among the poorest households, flood exposure increased the likelihood of low birthweight by 5% compared with households not exposed to floods.For agricultural households, climate-induced low temperatures and low rainfall before conception were associated with increases of 1.09 and 1.53 percentage points, respectively, in infant mortality rates.Excessive monsoon rainfall during pregnancy and the first year after birth has also been linked to undernutrition and a higher likelihood of stunting among children under five.Air pollution, meanwhile, presents another significant risk. Indian mothers exposed to higher levels of ambient PM2.5 pollution during pregnancy had 67% higher odds of delivering preterm and 37% higher odds of having a low-birthweight baby, even after accounting for temperature, the report notes.The findings point to overlapping environmental risks for mothers and babies, particularly as fossil fuel combustion contributes both to climate change and air pollution.India's heat plans have gaps in protecting pregnant womenDespite having several large-scale maternal and newborn health programmes, India has yet to systematically integrate heat protection into routine maternal care, the ZCA analysis finds.The India Newborn Action Plan aims to reduce neonatal mortality and stillbirth rates to fewer than 10 per 1,000 live births by 2030. The Pradhan Mantri Surakshit Matritva Abhiyan (PMSMA) seeks to improve maternal and foetal health through early detection and management of complications. However, these programmes were not specifically designed to address the risks extreme heat poses during pregnancy.India has begun taking steps towards addressing this gap. The Union Ministry of Health and Family Welfare has issued guidelines on heat and pregnancy for healthcare professionals and community health workers. These cover heat-risk assessment, identification of high-risk pregnancies, warning signs, cooling, hydration, referrals and family preparedness.The National Programme on Climate Change and Human Health and state-level action plans on climate change and human health also provide avenues to incorporate maternal heat protection into healthcare systems.India has more Heat Action Plans than any other low- or middle-income country. Around 60% of Indian state Heat Action Plans recognise pregnant women as a vulnerable group, compared with 46% of plans elsewhere in the world.However, recognition has not consistently translated into specific protective measures. A review of 35 plans covering all states and Union Territories, 19 Heat Action Plans and 16 State Action Plans on Climate Change, found that 12 contained no recommendations for pregnant or lactating women.The remaining 23 plans listed 214 strategies referring to these groups, either directly or as part of wider vulnerable populations. But only 40 strategies specifically targeted pregnant or lactating women. Most focused on changing individual behaviour rather than structural interventions such as cooling facilities and health-system support.The report also points to concerns over the design and implementation of Heat Action Plans, including inadequate attention to local contexts and poor targeting of vulnerable populations.The Heat in Pregnancy-India (HiP-India) project is currently studying three climate zones in the country to understand the mechanisms linking heat exposure to birth outcomes. It is also reviewing existing Heat Action Plans to identify areas that need strengthening.Meanwhile, healthcare professionals are reporting growing concerns about the effects of heat on pregnant women. A September 2026 Wellcome Trust survey of 1,000 maternal healthcare professionals across five countries, including India, found that 73% had seen an increase in heat-related cases or complications among pregnant women over the preceding five years. Overall, 92% wanted more training and resources to protect pregnant women. These figures represent the five-country survey and are not India-specific.The ZCA analysis argues that protecting mothers and babies will require heat risk to become a routine consideration in antenatal care, community maternal health services and health-system preparedness.Better antenatal care, cooling facilities and early-warning systems could prevent some of the additional preterm births associated with climate change, the researchers say, although such interventions may not eliminate the entire burden.As India prepares for increasingly hotter conditions, the findings underline the need to look beyond heat-related illnesses among the general population and recognise pregnancy and newborn health as critical components of climate adaptation.