Gender is believed to be an independent risk factor for the development of post-dural puncture headache, but there are some of the inconsistencies in the available data. This systematic review examined a total of 18 trials (2,163 males, 1,917 females). The odds of developing a post-dural puncture headache were significantly lower for male than nonpregnant female subjects (odds ratio = 0.55; 95% confidence interval, 0.44-0.67). Although the authors found that nonpregnant female subjects seem to have a higher incidence of post-dural puncture headache than males, the etiology behind these findings is not clear from the current meta-analysis.