Tension-type headache and women: do sex hormones influence tension-type headache?

Most of the world's population has suffered from a tension-type headache (TTH) at some point in their lives. The pathophysiology of this disease is not well understood, but TTH shares many features with migraine, leading to the belief that TTH and migraine may be on different ends of the same disease spectrum. There are many shared triggers between migraine and TTH, menstruation being one of them. Does menses being a trigger for TTH make TTH more like migraine, or does the role of sex hormones in TTH give us insight into the unique pathophysiology of this disease? This article will review TTH, concentrating on the role of sex hormones as a trigger for TTH.