Pregnancy Hormone Estriol May Help MS

For many years, the medical community has observed that a woman’s MS may be less severe during pregnancy. A pregnancy hormone named estriol is produced by the placenta and may cause this remission in symptoms.

The immune system normally works by recognizing foreign bodies and destroying them to protect itself from disease. MS is thought to occur when the immune system becomes overactive and destroys the body’s own myelin (the protective covering on nerves) as well as the nerves themselves. Researchers believe that estriol may control the immune system so that it does not attack the fetus. In animal models of MS, estriol can ameliorate a model of MS disease and cause a shift in immune system reactions.

A recent study found that six women with relapsing-remitting MS showed improvements in symptoms, along with a significant decrease in enhancing lesions as shown on MRI, when taking estriol over a six-month period. These same women experienced a worsening when the treatment was stopped for another six-month period. When treated a second time at the end of the study, improvement returned. Improvement was not observed at any time in four women with secondary-progressive MS, suggesting that this treatment may only be effective for women in earlier stages of the disease. Its effect on men is not known.

The estriol was given orally in pill form and caused no major side effect other than menstrual irregularities. The male hormone progesterone was given with the estriol to counter its possible increased risk of uterine cancer. Larger, placebo-controlled studies are needed to determine estriol’s long-term safety and efficacy. Estriol may also have the potential to similarly affect other autoimmune diseases that respond favorably during pregnancy.

Sources for this article include:

Reuters Health (by Jacqueline Stenson, September 25, 2002)

Sicotte, et al, Treatment of Multiple Sclerosis with the Pregnancy Hormone Estriol, Annals of Neurology, vol. 52, pp. 421-428, 2002.