To the Editor.
—Multiple sclerosis (MS) is a demyelinating disease of unknown cause, in which disordered immune regulation is thought to play a pivotal role. There is no cure for MS, and current therapies for disease progression are unsatisfactory. Considerable evidence indicates that pregnancy in MS (and in other autoimmune diseases) is associated with a reduction in clinical disease activity, with exacerbations occurring at an increased rate post partum.1,2 These observations suggest that the protective effect of pregnancy is due to an immunosuppressive factor(s) that increases during pregnancy and declines following delivery. This factor is of great interest because its identification could lead to a better understanding of MS and to the development of new therapies for disease progression.It has been proposed that the amelioration of MS during pregnancy may be related to the immunosuppressive effects of hormonal steroids or pregnancy-associated proteins.1 Experimental allergic encephalomyelitis (EAE), the
Schwartz GG. Hypothesis: Calcitriol Mediates Pregnancy's Protective Effect on Multiple Sclerosis. Arch Neurol. 1993;50(5):455. doi:10.1001/archneur.1993.00540050009006