We conducted a retrospective case-control study of 1,097 women in Massachusetts and Rhode Island, USA, to examine the association between stillbirth related to placental abruption or placental insufficiency and maternal exposure to traffic-related air pollution. We utilized distance to nearest roadway proximity metrics as a proxy for traffic-related air pollution exposure. No meaningful increase in the overall odds of placental-associated stillbirths was observed (adjusted OR: 1.1, 95% CI: 0.5-2.8). However, mothers living within 50 m of a roadway had a 60% increased odds of experiencing a stillbirth related to placental abruption compared to mothers living greater than 200 m away. This suggestive finding was imprecise due to the small case number in the highest exposure category (95% CI: 0.6-4.0). Future studies of placental abruption with more precise exposure assessments are warranted.
Keywords: Stillbirth; placenta; roadway proximity; traffic-related air pollution (TRAP).