The Avon Longitudinal Study of Parents and Children (ALSPAC) total sample included 15,247 pregnancies from women residing in Avon, UK with expected due dates between April 1991 and December 1992, resulting in 15,458 fetuses. Of this total sample, 14,775 were live births and 14,701 were alive at 1 year of age. Additional details are available from [29]. Please note that the study website contains details of all the data that is available through a fully searchable data dictionary (http://www.bris.ac.uk/alspac/researchers/data-access/data-dictionary/). Ethical approval for the study was obtained from the ALSPAC Ethics and Law Committee, Bristol University, and Virginia Commonwealth University.
