Extreme temperatures during pregnancy and adverse birth outcomes: Evidence from 2009 to 2018 U.S. national birth data

Abstract

We provide the first estimates of the impacts of prenatal exposure to extreme temperatures on infant health at birth using the latest national birth data from 2009 to 2018 from all U.S. states. We consistently find that an additional day with mean temperature greater than 80°F or less than 10°F increases preterm births and low birthweight. Strikingly, the adverse effects are borne disproportionately by Black and Hispanic mothers, suggesting that the projected increase in extreme temperatures may further exacerbate the existing birth health disparities across different race/ethnicity groups. We also contribute by investigating the impact of deviations from the normal weather pattern, to identify the extreme weather events after accounting for the adaptation response. We find that prenatal exposure to extreme heat two standard deviations above county's historic average induces preterm births and NICU admissions, particularly for mothers whose pregnancies overlap with summer months. These results are timely and policy relevant, considering the recent weather trends with rising temperatures and frequent extreme weather events.

The impact of extreme temperatures on birth outcomes in the Netherlands: a nationwide population-based study

“…These results are in line with the conclusions from previous studies. 18,21 We expanded previous work by investigating whether the observed effect on LBW is related to a preterm delivery (PTB), growth restriction (operationalized as SGA), or both. Given that we observed an effect of exposure to hot days (> 20 °C) for both SGA and PTB, it is sensitive to think that the impact observed on LBW is related to both, preterm deliveries and growth restriction.…”

“…Previous research has proposed that aside from biological mechanisms, behavioural responses to unusually warm temperatures might also contribute to the effect observed on adverse outcomes. 21,57 For instance, pregnant women in historically cooler countries might spend more time outdoors when temperatures are unusually warm and engage in more physical activity, potentially raising the risk of fatigue and dehydration. 21,57 Furthermore, studies aiming at assessing the role of air pollution as a potential mediator (and moderators) for the effect of temperature on health at birth are needed.…”

“…13,15,16 Recently, a small number of studies, mostly from the field of economics, have been able to establish a causal relationship between extreme temperatures and health at birth. [17][18][19][20][21][22] These studies used a "binned" approach to modelling the temperature-response function which allows for nonlinear effects of temperature on health outcomes, facilitates the control for sources of confounding, and is suitable for different types of outcomes. 23 This approach has a clear definition of exposure, i.e., the number of days in the gestational period with temperatures falling within prespecified degree ranges (bins).…”

“…24 Findings mainly support extreme high temperatures' impact on LBW, but other outcomes are understudied. 17,18,21,22 LBW can arise from preterm delivery, intrauterine growth restriction (SGA), or a combination. 25 As extreme temperatures affect SGA and PTB through distinct mechanisms, 10,26 causal evidence is crucial.…”

Climate change, health and sustainable healthcare: The role of health economics

“…Health economists have been working on certain aspects of these challenges more than on others, and these different areas of potential contribution have not previously been brought together in one place. Health economics work in this space includes the impacts of extreme weather events (Escobar Carías et al., 2022; Lee & Li, 2021; Ponnusamy, 2022), extreme temperatures (Adélaïde et al., 2022; Cil & Kim, 2022; Masiero et al., 2022; Mullins & White, 2019), air pollution (Giaccherini et al., 2021; Luechinger, 2014; Palma et al., 2022), and vector‐borne diseases (Sanfelice, 2022).…”