Successful pregnancy after natalizumab-associated progressive multifocal leukoencephalopathy in a patient with multiple sclerosis.

We report the case of a post-progressive multifocal leukoencephalopathy (PML), multiple sclerosis (MS) patient with an uncomplicated pregnancy and delivery. A 28-year-old woman on natalizumab (total of 49 infusions) was diagnosed with PML due to typical magnetic resonance imaging (MRI) and clinical presentation. John Cunningham virus (JCV) was detected in the cerebrospinal fluid (CSF) during the immune reconstitution inflammatory syndrome (IRIS). Nine months after PML onset, JCV negativity in the CSF was observed. MS was stabilised with dimethyl fumarate (DMF), and 18 months later, a desired pregnancy was reported, resulting in the birth of a healthy boy. Our report gives new hope regarding family planning for post-PML patients.