Greenspace and Land Cover Diversity During Pregnancy in a Rural Region, and Associations With Birth Outcomes

Beneficial effects on health outcomes have been observed from exposure to spaces with substantial green vegetation ("greenspace"). This includes studies of greenspace exposure on birth outcomes; however, these have been conducted largely in urban regions. We characterized residential exposure to greenspace and land cover diversity during pregnancy in rural northern New England, USA, investigating whether variation in greenspace or diversity related to newborn outcomes. Five landscape variables (greenspace land cover, land cover diversity, impervious surface area, tree canopy cover, and the Normalized Difference Vegetation Index) were aggregated within six circular zones of radii from 100 to 3,000 m around residential addresses, and distance to conservation land was measured, providing a total of 31 greenspace and diversity metrics. Four birth outcomes along with potentially confounding variables were obtained from 1,440 participants in the New Hampshire Birth Cohort Study. Higher greenspace land cover up to 3,000 m was associated with larger newborn head circumference, while impervious surface area (non-greenspace) had the opposite association. Further, birth length was positively associated with land cover diversity. These findings support beneficial health impacts of greenspace exposure observed in urban regions for certain health outcomes, such as newborn head circumference and length but not others such as birthweight and gestational age. Further our results indicate that larger radius buffer zones may be needed to characterize the rural landscape. Vegetation indices may not be interchangeable with other greenspace metrics such as land cover and impervious surface area in rural landscapes. Previous studies show that places with green plants can improve people's health. These places, called "greenspace," may be in city parks or suburban or rural areas. Some studies (mostly in cities) show that a mother's exposure to greenspace during pregnancy can lead to a healthier newborn. Here, we examine how different types of greenspace affect birth outcomes in a more rural area in New England, USA. We used definitions of greenspace based on land cover type (such as forest or farmland); diversity or mixture of land cover; impervious surfaces (pavement and buildings); tree cover; a "vegetation index" calculated from satellite imagery; and the distance from a house to the nearest protected conservation land. Having more greenspace near a home was associated with larger newborn head circumference. Having a diverse mix of land cover types was associated with longer newborn body length. However, the effects of varying amounts of greenspace on health were relatively small in this predominantly rural area, where most homes have at least some greenspace nearby. When studying greenspace and birth outcomes, we compensated for the effects of other factors affecting pregnancy and newborn health, such as the mother's age, exercise, and tobacco use. Greenspace land cover and diversity associated with larger head circumference and longer birth length, respectivelyOur findings were seen for larger buffer zones and different outcomes than reported in urban studiesResults for measures of biodiversity suggest further research using these measures