Chronic exposure to fine particulate matter emitted by traffic affects reproductive and fetal outcomes in mice

Air pollution is an important environmental health risk factor that can result in many different gestational and reproductive negative outcomes. In this study, we have investigated the effects of two different times of exposure (before conception and during pregnancy) to urban ambient particulate matter on reproductive and pregnancy outcomes in mice. Using exposure chambers receiving filtered (F) and non-filtered (NF) air, we observed that exposed females exhibited changes in the length of estrus cycle and extended estrus and, therefore, a reduction in the number of cycles during the studied period (F 2.6±0.22 and NF 1.2±0.29, p=0.03). The mean number of antral follicles declined by 36% ( p=0.04) in NF mice (75±35.2) compared to F mice (118.6±18.4). Our results further indicate a significant increase in time necessary for mating and decreased fertility and pregnancy indices ( p=0.003) in NF couples. Mean post-implantation loss rates were increased by 70% ( p⩽0.005) in the NF2 group (exposed before and during pregnancy to NF air) compared to the F1 group (exposed before and during pregnancy to F air) and were influenced by both pre-gestational ( p