Local mobility among pregnant women with and without asthma

Abstract

Background/aim: Studies evaluating environmental effects on perinatal health often estimate exposures based on residential address assuming pregnant women are stationary. Pregnant women are frequently mobile but their mobility is understudied. We investigate local and residential mobility across pregnancy in a prospective cohort of pregnant women. Methods. B-WELL-Mom is a prospective cohort study of 418 pregnant women with and without asthma. This analysis includes 277 women who participated in the local mobility sub-study. Participants carried a GPS-activated device to assess locational changes (i.e., local mobility) throughout pregnancy. They also self-reported residential mobility (i.e., residential relocation) during each trimester and ~4 months post-partum. GPS locations and successive residential addresses throughout pregnancy were geocoded to determine local and residential mobility. Results. At enrollment, 69 women (24.9%) had no asthma, 98 (35.4%) had well-controlled asthma, and 110 (39.7%) had poorly-controlled asthma. The proportion of time women spent inside their residential census tract increased from 30.5% during the first trimester to 41.1% during the third trimester. Women without asthma spent less time in their census tract compared to women with asthma especially during later pregnancy (trimester 3: 32% vs. 43%). During postpartum, women without asthma spent 51.9% of their time inside their census tract, whereas women with well-controlled asthma and poorly controlled women spent 56.5% and 76.3% of the time within their census tract, respectively. Approximately 27% of women moved during pregnancy, with 68% of movers relocating to a different census tract. Conclusions. Pregnant women are mobile beyond their residential address and local area. Local mobility declined through pregnancy, and women with asthma had less local mobility than women without asthma. Residential relocation was common, and a significant proportion of movers relocate to a different area. Studies assessing environmental effects on perinatal health should pay attention to local and residential mobility to improve exposure assessment.