Agay-Shay and colleagues analyse a large Israeli birth cohort to address whether birth outcomes were related to levels of ‘surrounding greenness’ (ie, density of vegetation) around the mother's place of residence.1 Their study builds on the existing green space and health literature,2 and contributes to recent explorations of whether maternal exposure to green space might benefit the unborn child.3–7 The research included almost 40 000 birth records, making it the second largest analysis of green space and pregnancy outcomes to date. Importantly, this study focuses on an environmental factor with the potential to support human health and well-being, rather than on pathogenic environments.

The surrounding greenness of the maternal neighbourhood was positively related to birth weight and to reduced risk of low-birth-weight births, and these findings were not sensitive to whether greenness was measured within 100, 250 or 500 m of the home. Separate analyses by level of neighbourhood socioeconomic deprivation revealed the strongest relationships in the most deprived areas. Pregnancy length (gestational age and preterm delivery) was not associated with surrounding greenness in this study.

The study corroborates recent findings from the USA, Spain and Germany. In these settings, researchers have consistently found that surrounding greenness or tree-canopy cover is related to foetal growth,3–7 but that associations with pregnancy length or complications are absent or inconsistent.4–6 And while effect modification by area-level deprivation has not been addressed elsewhere, the Spanish studies report strongest relationships between surrounding greenness and birth weight for mothers with …