Oral Contraceptive Won't Hurt, Might Help MS

Use of an oral contraceptive by women with multiple sclerosis (MS) did not appear to increase risk of relapse and may have exerted some protective effect, researchers found in a recent analysis of data from a long-term observational study.

Women with MS who had previously used an oral contraceptive (OC), before starting an injectable disease-modifying study medication, were found to have a statistically significantly lower annualized relapse rate than those who had never used an OC. Those who were currently using an OC when they received a study medication, which was administered within two years of diagnosis, also had a lower relapse rate than those never using an OC, albeit not statistically significantly lower.

"The current findings from a real-world cohort of women with early MS provide reassurance that use of common OC formulations does not appear associated with increased risk of relapses, and in the case of prior use, may even be protective," said lead author Riley Bove, MD and colleagues at Partners Multiple Sclerosis Center, Department of Neurology, Brigham and Women's Hospital, Boston, Massachusetts.

The findings emerged from an assessment of 162 women with MS or clinically isolated syndrome having a known OC usage who were among those enrolled in the Comprehensive Longitudinal Investigation of Multiple Sclerosis at the Brigham and Women's Hospital (CLIMB) study comparing long-term outcomes between two different disease modifying treatments, glatiramer acetate (Copaxone/Teva; Glatopa/ Novartis) and interferon beta-1a (Avonex, Biogen).

An equal number of women (81) received each medication, with no significant difference between the treatment groups in demographics, or in baseline illness severity as measured on the Expanded Disability Status Scale (EDSS). Within the two treatment groups, however, the mean ages of current-, past-, and never-OC users were 31.4, 40.3, and 37.9 years, respectively. There was also wide variability in the particular OC formulation used, with the three most common being a combination of ethinyl estradiol with either norgestimate, drospirenone, or norethindrone.

The annualized relapse rate over the 8.5-year follow-up was not significantly different across the OC groups, although comparisons between each group revealed a significantly lower relapse rate among past users then never users (relative risk [RR] =0.64, p=0.031), and a numerically lower relapse rate in current OC users than never users (RR=0.97, p=0.91).

The findings were unaffected by the particular study medication received. The investigators acknowledge the possible influence of the differences in ages between OC groups but discount its contribution, noting that the younger patients who might be expected to have more frequent relapse were the current OC users who did not evidence that course.

The investigators hope that their findings are reassuring to women with MS who are using, or considering using an OC. They note previous studies which suggest a neutral or protective effect in relapsing-onset MS, although the opposite effect has been found in primary progressive MS. They also cite an intervention study in which a reduction in magnetic resonance imaging (MRI)-visualized lesions followed the addition of an OC to treatment with injectable interferon beta-1a.

Bove and colleagues hypothesize that an OC may exert protective effect in MS by stabilizing hormonal levels, which could temper fluctuations in the inflammatory cascade that leads to new lesions and clinical relapses.

The study of MS relapse rates in women relative to their use of oral contraceptives was posted on-line in February in Multiple Sclerosis Journal. It is entitled, "Oral Contraceptives and MS Disease Activity in a Contemporary Real-World Cohort.”

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