Temperature extremes and stillbirth risk in Bihar, India: a panel data analysis, 2009–2019

Rising temperatures have become one of the most critical public health challenges in the era of global climate change. Frequent exposure to temperature extremes not only threatens the health of pregnant women but also poses significant risks to fetal development. Increasing evidence from global studies indicates that both high and low temperature exposures are associated with adverse birth outcomes such as preterm birth, low birth weight, and stillbirth. However, this issue remains inadequately explored in the Indian context, particularly through longitudinal district-level analyses. The present study examines the relationship between ambient temperature and stillbirth rate across districts of Bihar from 2009 to 2019, employing fixed-effects panel regression, distributed lag, and distributed lag non-linear models. The findings reveal a significant non-linear U-shaped relationship between temperature and stillbirth rate, indicating that exposure to either extreme high or low temperature substantially elevates the risk of stillbirth. Specifically, exposure to high temperatures around 35 °C or low temperatures near 18 °C increases stillbirth risk by approximately 7–14%. These results highlight the thermal sensitivity of pregnancy outcomes and the dual burden posed by temperature extremes. Despite certain limitations, the study underscores the need to integrate climatic factors into maternal health policy to enhance resilience and safeguard the health of mothers and their developing foetuses.