The authors acknowledge that neighbourhood opportunity cannot be solely defined by the proportion of poor households nor can two snapshots fully capture life- course experiences. This study nonetheless makes an important contribution to the advancement of life- course research by taking an approach that is both more longitudinally- and contextually- integrated than in previous research on birth outcome disparities. Future life- course studies of neighbourhood effects on birth outcomes should strive to capture a fuller picture of neighbourhood conditions (eg. interaction between neighbourhood poverty and residential segregation) as well as life- course trajectory.