Background: We monitored exposure to fine particulates (PM(2.5)), ozone, nitrogen dioxide (NO(2)), and ambient temperature for pregnant women with and without asthma. Methods: Women (n = 40) from the Breathe-Well-Being, Environment, Lifestyle, and Lung Function Study (2015-2018) were enrolled during pregnancy and monitored for 2-4 days. Daily pollutants were measured using personal air monitors, indoor air monitors, and nearest Environmental Protection Agency's stationary monitors based on GPS tracking and home address. Results: Personal-monitor measurements of PM(2.5), ozone, and NO(2) did not vary by asthma status but exposure profiles significantly differed by assessment methods. EPA stationary monitor-based methods appeared to underestimate PM(2.5) and temperature exposure and overestimate ozone and NO(2) exposure. Higher indoor-monitored PM(2.5) exposures were associated with smoking and the use of gas appliances. The proportion of waking-time during which personal monitors were worn was ~56%. Lower compliance was associated with exercise, smoking, being around a smoker, and the use of a prescription drug. Conclusions: Exposure did not vary by asthma status but was influenced by daily activities and assessment methods. Personal monitors may better capture exposures but non-compliance merits attention. Meanwhile, larger monitoring studies are warranted to further understand exposure profiles and the health effects of air pollution during pregnancy.