To provide the largest-to-date meta-analytic evidence of oral contraceptives’ (OCs) impact on MS relapse and future risk of development.
We identified 20 relevant studies. Ever OC use did not increase the future risk of MS (RR: 1.07, 95% CI: 0.92-1.24, I2: 66.5%). However, upon elimination of an outlier, a modest association was revealed (RR: 1.14, 95% CI: 1.00-1.30, I2: 51.8%). A pooled analysis of individuals with past use of OCs yielded no significant association with MS development. This observation was sustained following a leave-one-out test (RR: 1.23, 95% CI: 0.99-1.52, I2: 0%). Similarly, a current use of OCs did not put women at an increased MS risk. Duration of OC consumption appears not to influence MS risk either (5 years or more: 95% CI: 0.88-1.52, I2: 51.7%; 2 years or less: 95% CI: 0.95-1.25, I2: 0%). Finally, to assess the differential impact of OC types, a meta-analysis of progesterone-only OCs concluded insignificant MS future risk following consumption. A systematic literature review suggests that OCs are associated with lower expanded disability status scale and MS severity scores, though with no unanimous consensus on relapse rate reductions.
Collectively, these findings challenge historical doubts and support the reassurance of OC safety in women at risk for or living with MS.