Chronic disabling postpartum headache after unintentional dural puncture during epidural anaesthesia: a prospective cohort study

Background: Unintentional dural puncture with an epidural needle complicates approximately 1% of epidural anaesthetics and causes an acute headache in 60-80% of these patients. Several retrospective studies suggest an increased risk of chronic headache. We assessed the relationship between unintentional dural puncture and chronic disabling headache, defined as one or more functionally limiting headaches within a 2-week interval ending 2, 6, and 12 months postpartum. Methods: In this prospective observational study, parturients who experienced unintentional dural puncture were matched 1:4 with control patients. Patients completed questionnaires regarding characteristics of headache and back pain pre-pregnancy, during pregnancy, immediately postpartum, and at 2, 6, and 12 months postpartum. The primary outcome was prevalence of disabling headache in the past 2 weeks, assessed at 2 months postpartum. Secondary outcomes included prevalence and characteristics of headache and back pain at these time points. Results: We enrolled 99 patients. At 2 and 6 months postpartum, the prevalence of disabling headache was greater among patients with unintentional dural puncture than matched controls (2 months, 74% vs 38%, relative risk 1.9, 95% confidence interval 1.2-2.9, P=0.009; 6 months, 56% vs 25%, relative risk 2.1, 95% confidence interval 1.1-4.0, P=0.033). There was no difference in the prevalence of back pain at any time point. Conclusions: Our prospective trial confirms retrospective studies that chronic headache is more prevalent among women who experienced unintentional dural puncture compared with controls who received uncomplicated neuraxial anaesthesia. This finding has implications for the. patient consent process and recommendations for long-term followup of patients who experience unintentional dural puncture.