Relapsing remitting multiple sclerosis (RRMS) primarily affects women of child-bearing age. Relapses during pregnancy are rare but increase in the early post partum period. Disease-modifying therapies (DMT) use during pregnancy is off label. DMT discontinuation is advised prior to conception by most pharmaceutical companies, this may be unrealistic in patients with highly active disease. Therapeutic plasma exchange (PLEX) is effective and safe in autoimmune disorder relapses during pregnancy.

A 26-year-old with active RRMS since 2011 decided to attempt conception. The diagnosis of MS was based on clinical and radiological criteria with positive OCB. She had relapsed multiple times on interferon beta-1a prior to commencing fingolimod. She was stable on fingolimod for 6 years. The patient had 2 relapses after stopping fingolimod for conception. Both relapses responded to steroids. The patient recommenced fingolimod and discontinued it 3 months later during early pregnancy. At 16/40 and 20/40 weeks pregnant the patient suffered severe spinal cord relapses with acute paraparesis and sensory ataxia such that by 21/40 pregnant she was requiring a wheelchair. MR imaging demonstrated significant progression of disease. There was minimal response to IV methylprednisolone (IVMP). The patient improved to walking with frame after prolonged therapeutic plasma exchange (PLEX). IV natalizumab was given monthly until the post partum period with improvement to walking unaided or occasional use of stick. She gave birth to a healthy baby girl with no post-partum thrombocytopenia. As the patient had a high JCV index she was transitioned from natalizumab to alemtuzumab treatment several months later.