This derived field, calculated from episode start date (epistart) and date of birth (dob), contains the patient's age in whole years (From 1 to 115 (1990-91 to 1994-95) and from 1 to 120 (1995-96 onwards)).

For patients under 1 year old, special codes in the range 7001 to 7007 apply.

7001 = Less than 1 day

7002 = 1 to 6 days

7003 = 7 to 28 days

7004 = 29 to 90 days (under 3 months)

7005 = 91 to 181 days (approximately 3 months to under 6 months)

7006 = 182 to 272 days (approximately 6 months to under 9 months)

7007 = 273 to 364 days (approximately 9 months to under 1 year)

null = Not applicable (other maternity event or not known)