Hormonal Replacement Therapy Does Not Affect Self-estimated Pain or Experimental Pain Responses in Postmenopausal Women Suffering From Fibromyalgia: A Double-blind, Randomized, Placebo-controlled Trial

Fibromyalgia is a condition that preferentially affects women. Sex hormones, and in particular estrogens, have been shown to affect pain processing and pain sensitivity, and estrogen deficit has been considered a potential promoting factor for fibromyalgia. However, the effects of estrogen treatment in patients suffering from fibromyalgia have not been studied. Twenty-nine postmenopausal women were randomized to either eight weeks of treatment with transdermal 17β-estradiol (50 ug daily) or placebo according to a double-blind protocol. A self-estimation of pain, a set of quantitative sensory tests measuring thresholds to temperature, thermal pain, cold pain and pressure pain, and a cold pressor test were performed at three occasions: before treatment, after eight weeks of treatment, and twenty weeks after cessation of treatment.