00424nas a2200157   4500000000100000000000100001008004100002100001300043700001500056700001200071700001500083245011800098300001100216490000700227022003200234       2004                            d1 aJ. Hardy1 aT. Holford1 aG. Hall1 aM. Bracken00aStrategies for identifying pregnancies in the automated medical records of the General Practice Research Database  a749-590 v13  a1053-8569 (Print) 1053-8569