Summary: In a small-scale, early-phase trial of the hormone estriol, a form of estrogen, women with relapsing-remitting MS showed decreases in MRI-detected brain lesion activity and immune responses during treatment, suggesting that additional study of estriol is called for to determine longer-term efficacy and safety.

• Women who have MS and are pregnant often experience fewer MS symptoms and relapses, especially during the second and third trimester. Because the hormone estriol is elevated during later stages of pregnancy, and mice given pregnancy levels of estriol were shown to have fewer symptoms of an MS-like disease, the hormone was considered as a candidate for testing against MS.
• Estriol was well tolerated. Six women with relapsing-remitting MS experienced significant decreases in brain lesion numbers and volume, as well as reductions in levels of immune proteins indicative of inflammation.[More]