2.2. Maternal exposure to green space during pregnancy

Questionnaires were used to retrieve information on the maternal residential addresses during the pregnancy, which were geocoded to calculate green space exposure at 100 m and 1000 m around the residential address. Green space was calculated on the land cover data of the high-resolution (1 × 1 m) 2013 Green Map of Flanders (Groenkaart Vlaanderen) commissioned by the Agency for Nature and Forest (Agentschap voor Natuur en Bos), using the same method described elsewhere (Dockx et al., 2021). The map identifies as green space the non-agricultural vegetation and distinguishes three measures: (1) high green space referring to vegetation height >3 m; (2) low green space referring to vegetation height <3 m; and (3) total green space referring to vegetation cover (that is the sum of 1 and 2). Geographic Information System functions (ArcGIS 10 software) were used to carry out the analyses.