The relationship between body mass index and post-dural puncture headache in obstetric patients.

Background: Difficult epidural insertion and accidental dural puncture are more likely in the obese pregnant population. Low-level evidence suggests that the risk of post-dural puncture headache declines as body mass index increases.

Methods: We retrospectively reviewed prospective data on 18315 obstetric epidural and combined spinal-epidural insertions, identifying 125 (0.7%) accidental dural punctures or post-dural puncture headaches between 2007 and 2012. The audit record and patient medical record were examined to determine patient body mass index, headache characteristics and use of a therapeutic epidural blood patch. Women were classified into two groups: non-obese (body mass index <30 kg/m2, Group <30) or obese (body mass index ⩾30 kg/m2, Group ⩾30). Statistical analysis was by chi-square or Fisher exact tests, with P<0.05 considered significant.

Results: Compared to Group <30 (n=65), women in Group ⩾30 (n=60) did not significantly differ in the incidence of post-dural puncture headache (82% vs. 80%, P=0.83); its intensity (severe 36% vs. 23%, P=0.34); or the need for epidural blood patch (57% vs. 54%, P=0.81). Groups also did not differ significantly when confining analysis to those who had a witnessed accidental dural puncture (n=93) or to women with a body mass index >40 kg/m2 (n=10) vs. Group <30.

Conclusion: This retrospective study found no evidence that women of higher body mass index are less likely to develop a post-dural puncture headache or that the characteristics of the headache and use of epidural blood patch were different.