Reflection of prenatal exposure to wildfire smoke on reduced birth weight in 2015-2019

Abstract

Wildfire smoke contains many different types of air pollutants which are cause for concern. Studies on epidemiology have identified correlations between PM2.5 exposure to wildfire smoke and mortality, respiratory and cardiovascular morbidities, and may result in a reduction in birth weight. However, evidence from Indonesia is limited. For this study, a retrospective cohort epidemiological study was undertaken to quantify the Indonesian population’s exposure to wildfire-PM2.5. We present 9652 (88%) records of newborns to identify an association between fire-sourced PM2.5 and birth weight in Palangka Raya, Indonesia from 2015 to 2019. On an annual basis, geospatial, and season variations in wildfire-PM2.5 concentrations were observed using a satellite-based dataset from CAMS and used for gestational exposure to wildfire smoke. Applying a general linear model with birth weight (yi) as a continuous outcome, the relationship between PM2.5 exposure and low birth weight was examined. In addition, the binary outcome of low birth weight was analysed. A statistically significant difference in the birth weight reduction between infants delivered to mothers exposed to high levels of wildfire smoke and those exposed to low levels of wildfire smoke was observed over the entire time frame (2015-2019) (ρ-value < 0.001). In comparison to infants born to mothers exposed to lower concentrations, the birth weight of infants delivered to mothers exposed to high concentrations of PM2.5 in the third trimester decreased by 19.96%. A 1.9% reduction in birth weight could be caused by exposure during the fire-prevalent in the first trimester of pregnancy (ρ-value < 0.001). Since an estimation model predicted a 10 g/m3 increase in PM2.5 exposure between the first and last trimesters of pregnancy, variations in the second trimester did not significantly affect the association (ρ-value = 0.761). This emphasizes the significance of foetal development during these two trimesters. Exposure to pollution from wildfires contributes significantly to the global burden of newborns’ birth weight.