Abstract
BACKGROUND: Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease characterized by inflammatory demyelinating lesions affecting the optic nerve and spinal cord. As a rare condition, its clinical management—particularly in special populations such as pregnant patients—remains challenging. Inebilizumab, a B-cell-depleting biological agent used in aquaporin-4 immunoglobulin G-positive(AQP4-IgG+) NMOSD treatment, has demonstrated efficacy in disease control. However, no prior clinical reports have described its use in pregnant patients or the associated long-term maternal, fetal, and disease outcomes, leaving a critical gap in evidence. This case report, therefore, aims to address this knowledge deficit by presenting the first detailed account of an unexpected pregnancy in a patient receiving inebilizumab maintenance therapy, alongside the subsequent management strategies and outcomes. CASE PRESENTATION: We report a female patient with AQP4-IgG + NMOSD who experienced an unexpected pregnancy during three cycles of inebilizumab maintenance therapy. A multidisciplinary team (neurologists, obstetricians, and immunologists) collaborated to develop an individualized treatment plan. Following confirmation of pregnancy, her therapy was adjusted to low-dose methylprednisolone combined with azathioprine. During pregnancy, monitoring revealed persistently low B-cell counts, with low serum AQP4-IgG titers in the second trimester. The patient achieved a safe delivery and promptly resumed inebilizumab post-partum. Notably, no NMOSD recurrence was observed during the pre-conception, pregnancy, or post-partum periods. CONCLUSIONS: This study is the first to report the successful management of an unplanned pregnancy in AQP4-IgG + NMOSD patient receiving inebilizumab. It confirms the efficacy and safety of preconception targeted B-cell depletion, individualized immunotherapeutic maintenance under multidisciplinary guidance during pregnancy, and timely resumption of targeted therapy postpartum, providing important clinical references for optimizing perinatal treatment strategies in reproductive-aged AQP4-IgG + NMOSD patients.