Summary. A retrospective review of 600 obstetric case-notes, covering the years 1978 to 1984, was performed independently by two assessors. The medical response to 22 risk factors, recorded at booking by the midwife, was assessed. The medical staff recognized 69% of the risk factors recorded at booking and responded appropriately to 82% of these. The standard of care improved over the period studied. The accuracy of our conclusions was greatly enhanced by carrying out each assessment in duplicate with arbitration by a third assessor when necessary, and it is proposed that all audits of medical practice should themselves be audited in this way.