Review of research on residential mobility during pregnancy: consequences for assessment of prenatal environmental exposures

Abstract

Studies on environmental exposures during pregnancy often have limited residential history (e.g., at delivery), potentially introducing exposure misclassification. We reviewed studies reporting residential mobility during pregnancy to summarize current evidence and discuss research implications. A meaningful quantitative combination of results (e.g., meta-analysis), was infeasible owing to variation in study designs. Fourteen studies were identified, of which half were from the US. Most were case-control studies examining birth defects. Residential history was typically assessed after delivery. Overall mobility rates were 9–32% and highest in the second trimester. Mobility generally declined with age, parity, and socioeconomic status, although not consistently. Married mothers moved less frequently. Findings were dissimilar by race, smoking, or alcohol use. On the basis of the few studies reporting distance moved, most distances were short (median often <10 km). Results indicate potential misclassification for environmental exposures estimated with incomplete residential information. This misclassification could be associated with potential confounders, such as socioeconomics, thereby affecting risk estimates. As most moves were short distances, exposures that are homogenous within a community may be well estimated with limited residential data. Future research should consider the implications of residential mobility during pregnancy in relation to the exposure’s spatial heterogeneity and factors associated with the likelihood of moving and distance moved.

Associations between exposure to ambient benzene and PM2.5 during pregnancy and the risk of selected birth defects in offspring

“…However, Lupo et al found good agreement between measures estimated at the mother's residential addresses at the time of conception and delivery (Lupo et al, 2010). Furthermore, although a review of research on residential mobility found approximately 20% of the population moved during pregnancy, the median distance moved was less than 10 km (Bell and Belanger, 2012). Thus, the degree of misclassification of maternal exposure due to this temporally mismatched information may be small.…”

Sex-specific differences in fetal growth in newborns exposed prenatally to traffic-related air pollution in the PELAGIE mother–child cohort (Brittany, France)

“…Information on time-activity patterns, work, and residential mobility were not available and therefore exposure misclassification may have occurred (Bell and Belanger, 2012). Finally, NO 2 was used as a marker of traffic-related air pollution exposure but NO 2 itself cannot be said to be the causative agent of impaired fetal growth because it forms part of a complex and dynamic mixture of pollutants (WHO, 2006).…”

Ambient Air Pollution and Risk of Gestational Hypertension

“…Women may move during the exposure window of interest, although this should be nondifferential by case status. Maternal residential mobility during pregnancy tends to involve short-distance moves with a median of <10 km (42), which would likely leave most women in the same hospital referral region. Further, the simulation extrapolation demonstrated the robustness of the results for SO 2 exposure during the first trimester with a small to moderate measurement error rate.…”