Residential greenness: current perspectives on its impact on maternal health and pregnancy outcomes

Recent research in environmental epidemiology has attempted to estimate the effects of exposure to nature, often operationalized as vegetation, on health. Although many analyses have focused on vegetation or greenness with regard to physical activity and weight status, an incipient area of interest concerns maternal health and birth outcomes. This paper reviews 14 studies that examined the association between greenness and maternal or infant health. Most studies were cross-sectional and conducted in birth cohorts. Several studies found evidence for positive associations between greenness and birth weight and maternal peripartum depression. Few studies found evidence for an association between greenness and gestational age or other birth outcomes, or between greenness and preeclampsia or gestational diabetes. Several assessed effect modification by individual or area-level socioeconomic status and found that effects were stronger among those of lower socioeconomic status. Few studies conducted mediation analyses of any kind. Future research should include more diverse birth outcomes and focus on maternal health (especially mental health) and capitalize on richer exposure information during pregnancy rather than cross-sectional assessment at birth.