Relation of menstrual cycle phase to symptoms of rheumatoid arthritis.

Since progesterone and estrogen have been shown to exhibit anti-inflammatory/anti-arthritic activity, women with rheumatoid arthritis might be expected to have a reduction of some symptoms of rheumatoid arthritis during the postovulatory phase of the menstrual cycle when the plasma concentrations of these hormones increase. Daily examination of symptoms during 69 menstrual cycles in 14 patients with rheumatoid arthritis revealed that rheumatoid arthritis was significantly reduced during the postovulatory phase of the menstrual cycle. This reduction was clinically and statistically significant. The data presented in this report indicate that some of the "spontaneous" fluctuations in rheumatoid arthritis symptoms may be the result of changes in plasma concentrations of estrogen and progesterone.