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Many women have reported cyclical changes in MS symptoms and feel that their symptoms deteriorate two to three days prior to the onset of their period and improve once bleeding has started. A few small studies have confirmed this anecdotal evidence though more work needs to be done in this area.

A small study has found that 78% of women had premenstrual worsening of their MS symptoms in one or more of the menstrual cycles analysed. Symptoms most likely to increase premenstrually were arm and leg weaknesspain and nocturia (the need to go to the toilet during the night). A greater understanding of the effect of the menstrual cycle by both women with MS and health care professionals would help to reduce anxiety associated with an unexpected increase of symptoms.

Another small study has contradicted this finding, reporting no difference in symptoms between the phases of the menstrual cycle amongst 16 women. Another 7 women who were taking a combined oral contraceptive pill reported significantly higher weakness, numbness and tiredness during the pill-free interval compared with the phase during which they took the pill daily. Further studies of MS symptoms during the menstrual cycle and the effect of oral contraceptives are needed.

Treatment with the beta interferon drugs can sometimes cause irregular bleeding, early or late periods. A referral to a gynaecologist may be sought if this causes concern.



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  • Zorgdrager A, De Keyser J. Menstrually related worsening symptoms in multiple sclerosis. Journal of Neurological Science 1997;149(1):95-97. Summary
  • Houtchens MK, et al. Understanding fluctuations of multiple sclerosis across the menstrual cycle. International Journal of MS Care 2000;2(4):2 Full article (PDF 275kb)
  • Holmqvist P, et al. Symptoms of multiple sclerosis in women in relation to cyclical hormone changes. European Journal of Contraception and Reproductive Health Care. 2009;14(5):365-70. Summary
  • Nabavi SM, et al. Menstrual irregularities and related plasma hormone levels in multiple sclerosis patients treated with beta interferone. Acta Medica Iranica 2010; 48(1): 36-41. Summary

Last updated: 19 June 2013
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