Schertzinger M, et al. - Researchers assessed the relationships between sex hormones and fibromyalgia daily. They observed that both progesterone and testosterone had an association with lower self-reported pain. No correlation was found between estradiol fluctuations and self-reported pain. Elevation of pain is particularly evident when progesterone was low and cortisol was high. They thereby interpret that in women with fibromyalgia, sex hormones fluctuate normally, but could still contribute to pain severity.