Associations between multiple green space measures and birth weight across two US cities.

•Moderate to high correlation exists between different green space metrics across two US cities.•Positive associations existed between green space metrics and birth weight in unadjusted models.•Adjustment for maternal race/ethnicity and education removed most green space associations.•Positive associations between green space and birth weight remained in high density areas.•Further knowledge of individual/contextual factors that may confound or modify green space is needed.