Although statistics on mortality associated with extradural block in obstetrics are well known from Maternal Death Committees, accurate figures for morbidity are not available. To obtain such data, a joint project of the Royal College of Obstetricians and Gynaecologists and the College of Anaesthetists was undertaken. All obstetric units in the UK received a questionnaire asking for the incidence and nature of serious adverse events after extradural block for the period 1982–1986. Specific incidents requested included acute hypotension leading to cardiac arrest, acute hypotension requiring urgent and vigorous resuscitation, neurologic deficit of spinal nerves or cord lasting more than 1 month, and any other complications.