Residential mobility of pregnant women and implications for assessment of spatially-varying environmental exposures

Abstract

Nature Health studies on spatially-varying exposures (e.g., air pollution) during pregnancy often estimate exposure using residence at birth, disregarding residential mobility. We investigated moving patterns in pregnant women (n = 10,116) in linked cohorts focused on Connecticut and Massachusetts, U.S., 1988–2008. Moving patterns were assessed by race/ethnicity, age, marital status, education, working status, population density, parity, income, and season of birth. In this population, 11.6% of women moved during pregnancy. Movers were more likely to be younger, unmarried, and living in urban areas with no previous children. Among movers, multiple moves were more likely for racial/ethnic minority, younger, less educated, unmarried, and lower income women. Most moves occurred later in pregnancy, with 87.4% of first moves in the second or third trimester, although not all cohort subjects enrolled in the first few weeks of pregnancy. Distance between first and second residence had a median value of 5.2 km (interquartile range 11.3 km, average 57.8 km, range 0.0–4277 km). Women moving larger distances were more likely to be white, older, married, and work during pregnancy. Findings indicate that residential mobility may impact studies of spatially-varying exposure during pregnancy and health and that subpopulations vary in probability of moving, and timing and distance of moves.