Development of Late-Onset Preeclampsia in Association with Road Densities as a Proxy for Traffic-Related Air Pollution

INTRODUCTION: Previous epidemiological studies indicate an association between maternal exposure to air pollution and an increased risk of hypertensive disorders in pregnancy. We analyzed the association between the occurrence of mild/severe and early-/late-onset preeclampsia (PE) and traffic-related air pollution (TRAP). MATERIALS AND METHODS: Based on retrospective data, 50 pregnant women with PE were selected and matched with a control group of healthy pregnant women according to their age, parity, and number of fetuses. The total length of major roads around the women's home within a radius of 100, 200, 300, and 500 m and the distances from the domicile to the nearest 'first class' main road and freeway were used as a proxy indicator of TRAP. We compared a PE subgroup and control group in terms of their exposure to TRAP. RESULTS: Late-onset PE cases showed a significantly higher occurrence with density of major roads within a radius of 100-300 m compared to early onset cases (p = 0.006; 0.02; 0.04). In addition, a significantly shorter distance to the nearest 'first class' main road was observed in late-onset PE cases (p = 0.0078). CONCLUSIONS: Exposure to TRAP during pregnancy was associated with an increased risk for the development of late-onset PE.