Magnetic resonance evaluation of disease activity during pregnancy in multiple sclerosis

We followed two women with MS during pregnancy by means of serial unenhanced MR imaging. On each follow-up image, we assessed the number of new or enlarging lesions. Both women showed a decrease in MR disease activity during the second half of pregnancy and a return of MR disease activity to prepregnancy levels in the first months postpartum. These findings support the view that pregnancy reduces disease activity in MS.