Environmental exposures (physical, chemical and built environment) are associated with adverse pregnancy outcomes, and depending on timing of exposure relative to sensitive developmental windows, can be linked to early childhood and lifelong adverse health consequences for the child. Environmental exposures are also strongly associated with maternal health during pregnancy and the postpartum period. Air pollution especially is linked with increased systemic inflammation, greater cardiorespiratory risk and adverse metabolic health consequences. Exposure to certain components (eg, ultrafine particles) or sources (eg, traffic-related, wildfires, etc.) of air pollution during the preconception period and pregnancy has been linked to adverse pregnancy outcomes, especially for the smallest of particles (ultrafines <100nm in aerodynamic diameter) that can cross epithelial barriers in the alveolar region of the lungs and enter systemic circulation, translocating to other organs including the placenta and leading to systemic inflammation and oxidative stress.
Furthermore, environmental exposures are often spatially patterned along important racial/ethnic/socioeconomic lines and should be investigated in conjunction with co-occurring social determinants of health, especially given important disparities in maternal and child health. Most studies rely on neighborhood level or residential estimates as surrogates of personal exposures in pregnancy; however, these approaches often miss important personal mobility, time-activity patterns, and other contextual information that drive personal exposures. These coarse approaches typically suffer from exposure measurement error which can lead to severely attenuated or variable health effect estimates in epidemiological studies. They also do not typically consider residential mobility (or moving residences) and are not very finely spatially and temporally resolved.
Finally, given pregnancy itself is a very dynamic time, increased granularity and ability to monitor personal environmental exposures (and behaviors and health outcomes) continuously can provide important insights into longitudinal effects, acute effects, intermittent exposures and sensitive or critical windows of time. With advances in personal monitoring technologies, wearables, machine learning and mobile health approaches, these highly personalized, contextualized and resolved assessments of environmental exposures are now possible and can lead to important insights into placental development, function and its ultimate impacts on fetal health and pregnancy outcomes.