Thesis Abstract

Maternal exposure to air pollution has been a growing concern due to its potential impact on birth outcomes. This research project aimed to investigate the association between maternal exposure to air pollution and birth outcomes, focusing on outcomes such as preterm birth, low birth weight, and birth defects. The study utilized a retrospective cohort design, analyzing data from a large population-based sample of pregnant women. Air pollution exposure was assessed using various metrics, including particulate matter (PM), nitrogen dioxide (NO2), sulfur dioxide (SO2), and ozone (O3) levels. Maternal exposure levels were estimated based on residential addresses and air quality monitoring data. Statistical analyses were conducted to explore the relationship between air pollution exposure during pregnancy and birth outcomes. The findings of the study revealed a significant association between maternal exposure to air pollution and adverse birth outcomes. Higher levels of PM, NO2, and SO2 were linked to an increased risk of preterm birth and low birth weight. Additionally, exposure to O3 was found to be associated with a higher incidence of birth defects. These results suggest that maternal exposure to air pollution may have detrimental effects on fetal development and birth outcomes. Further analyses were conducted to investigate potential mechanisms underlying the observed associations. It was hypothesized that air pollution exposure during pregnancy could lead to systemic inflammation, oxidative stress, and placental dysfunction, ultimately affecting fetal growth and development. Understanding these pathways is crucial for developing targeted interventions to mitigate the impact of air pollution on maternal and child health. Overall, this research contributes to the existing literature on the effects of air pollution on birth outcomes and highlights the importance of environmental factors in maternal health. The findings underscore the need for policymakers to implement strategies to reduce air pollution levels and protect vulnerable populations, particularly pregnant women and infants. By raising awareness of the potential risks associated with air pollution exposure during pregnancy, this study aims to inform public health policies and promote a healthier environment for future generations.

Thesis Overview

BACKGROUND

The knowledge about air pollution effects on birth weight, prematurity, and small for gestational age (SGA) in low-exposure areas is insufficient.Maternal Exposure

OBJECTIVES:

The aim of this birth cohort study was to investigate whether low-level exposure to air pollution was associated with prematurity and fetal growth and whether there are sex-specific effects.Maternal Exposure

METHOD:

We combined high-quality registry information on 81,110 births with individually modeled exposure data at residence for nitrogen oxides (NO(x)) and proximity to roads with differing traffic density. The data were analyzed by logistic and linear regression with and without potential confounders.Maternal Exposure

RESULTS:

We observed an increased risk for babies being SGA when we compared highest and lowest NO(x) quartiles, adjusting for maternal age, smoking, sex, and year of birth. After additional adjustment for maternal country of origin and parity (which were highly intercorrelated), the increase was no longer statistically significant. However, in subgroup analyses when we compared highest and lowest NO(x) quartiles we still observed an increased risk for SGA for girls [odds ratio (OR)=1.12; 95% confidence interval (CI), 1.01-1.24); we also observed increased risk among mothers who had not changed residency during pregnancy (OR=1.09; 95% CI, 1.01-1.18). The confounders with the greatest impact on SGA were parity and country of origin. Concerning prematurity, the prevalence was lower in the three higher NO(x) exposure quartiles compared with the lowest category.Maternal Exposure