Long-term influence of combined oral contraceptive use on the clinical course of relapsing-remitting multiple sclerosis

OBJECTIVE: To assess the long-term effects of combined oral contraceptives (COCs) on the clinical course of relapsing-remitting multiple sclerosis (RRMS), focusing on disability progression and evolution to secondary-progressive multiple sclerosis (SPMS). DESIGN: Retrospective and exploratory study. SETTING: Academic medical center. PATIENT(S): A total of 174 women with clinically confirmed MS; of these, 33 had evolved to SPMS at the time of enrollment in the study, whereas 141 still had a relapsing-remitting form of disease. INTERVENTION(S): Women were interviewed to obtain gynecologic and obstetric history. MAIN OUTCOME MEASURE(S): Expanded Disability Status Scale (EDSS); Multiple Sclerosis Severity Score (MSSS); annualized relapse rate; evolution to SPMS. RESULT(S): Mean±SD duration of disease was 14.3±9.8 years. Compared with non-users of COCs, COC users had lower EDSS scores and MSSS only in the subset of the population with prior or current immunomodulatory treatment. Nonuse of COCs was a predictor of disease evolution in SPMS, whether treated or not with immunomodulatory drugs. The annualized relapse rate was not influenced by COC use. No differences in EDSS scores and evolution to SPMS depending on COC formulation were detected. CONCLUSION(S): Our results suggest that COC use is associated with a less severe disease and less severe evolution. Whether different doses or types of progestin may have different effects remains to be defined.