The CANOE study will provide an opportunity to collect novel longitudinal samples not available from the current CANOE birth cohorts, as well as enhanced and standardized environmental sampling in early life. One of the main goals of this study is to gather data and specimens, beginning in the prenatal periods, that will assess environmental exposures to toxins and microbes, and host characteristics including genetics, epigenetics, gene expression, the proteome and metabolome, microbial colonization and viral respiratory infections. The main study outcomes will be important interim conditions (e.g., recurrent wheeze, early multiple sensitization) that are highly associated with the development of asthma. Additional outcomes (perinatal outcomes, growth, neurocognitive development) will be collected as part of the collaborative Environmental Influences on Child Health Outcomes (ECHO)-wide Cohort Data Collection Protocol.