We report a prospective audit of 100 parturients who experienced accidental dural puncture by a Tuohy needle, while attending a tertiary referral obstetric unit juring the period 1993 1999. The post dural puncture headache rate was 81% and the diagnosis of dural puncture was delayed until presentation of the headache in 27% of these cases. The incidence of unrecognised dural puncture was not influenced by the technique used for identification of the epidural space. Intraspinal opioid administration after Jural puncture was associated with a significant reduction in the incidence of headache (P <0.04), There was no association between mode of delivery and post dural puncture headache. Deliberate cannulation of the subarachnoid space with an epidural catheter at the time of dural puncture, for continuous spinal analgesia or anaesthesia, did not affect the incidence of post dural puncture headache but was associated with a significantly reduced rate of epidural blood patch (43% versus 80%, P <0.01). Of those who developed post dural puncture headache, 48% were classified 'severe' and in 49% the headache presented within 24 h of dural puncture. There was a trend to earlier onset of headache (either immediate or within 24 h) when the epidural identification technique was loss-of-resistance to air rather than saline (54% versus 33%, P = 0.07). Twenty-eight percent of those suffering from post dural puncture headache were treated expectantly and 72% received a therapeutic blood patch. Of seven parturients who received sumatriptan, six found it ineffective and five subsequently received a blood patch. (C) 2001 Harcourt Publishers Ltd.