Prebirth effects of climate change on children's respiratory health

Prenatal climate change-related exposures impair the pulmonary health via two mechanisms.

First, exposure to all the environmental changes associated with the climate crisis, such as extreme weather events, heat, droughts and floods, food and water insecurity, infections, and maternal stress, can result in adverse pregnancy outcomes such as preterm birth, intrauterine growth retardation, small-for-gestational age (SGA), and low birth weight.  Exposure to environmental disasters and increased ambient temperature have been associated with increased preterm birth and low birth weight, for example during Hurricane Katrina in USA. Maternal stress can lead to changes in placental gene expression and modifications in the fetus's endocrine and immune environment. Elevated ambient temperatures cause changes in placental perfusion, increased oxidative stress and inflammatory cytokines production.

In addition, exposure to air pollution, temperature elevations, and increased maternal stress can lead to   changes in lung function and increases the risk of wheezing, atopy and airways infections.

The mechanisms underlying these outcomes are poorly understood but may be related to epigenetic modifications (differential DNA methylation affecting pathways mediating the expression of TH2-type cytokines), impaired placental function with oxidative stress and inflammation, and particulate matter translocation. For example, inhaled ultrafine particles <2.5 um can translocate systemically and accumulate in the developing organs of the fetus, including the lungs.

Exposure to air pollutants in the prenatal stage was associated with low FEV1 values in the pediatric age.

The impact of prenatal exposures to elevated temperatures and the synergistic effect with simultaneous exposure to air pollution and higher asthma incidence in children was described. This synergistic effect is worrying considering that ambient temperatures will continue to increase with climate change.

Climate change, particularly prenatal exposure to air pollution and increased temperatures, has been associated with increased airway infections in children; for example, exposure to increased daily temperature variations up to 1-year preconception and during pregnancy was associated with an increased frequency of childhood pneumonia, mainly in boys.

Bibliography
Aravind Yadav and Susan E. Pacheco. Prebirth effects of climate change on children's respiratory health. Curr Opin Pediatr 2023, 35:000-000. DOl:10.1097/MOP.0000000000001241