A Natural History Study of the Effect of Pregnancy on Aquaporin 4 Antibody-Positive Neuromyelitis Optica Spectrum Disorder (P6.160)

OBJECTIVE: To study the “natural history” of the effect of pregnancy on aquaporin 4 antibody-positive (AQP4+) neuromyelitis optica spectrum disorder (NMOSD), in a patient series not exposed to immunosuppressants and/or disease modifying therapies during pregnancy and in the preceding year. BACKGROUND: In multiple sclerosis (MS), there is increased relapse rate in early postpartum period. As in many autoimmune diseases, pregnancy may have an impact on NMOSD, a Th2-mediated disease. METHODS: Twenty female patients diagnosed with AQP4+ NMOSD at the Penang General Hospital, Penang, Malaysia were included. Their pregnancy history, number of relapses before pregnancy, during pregnancy and 1-year postpartum were reviewed. RESULTS: Four patients had never been pregnant. Eight patients had NMOSD onset many years (range: 7-44 years) after last pregnancy. Of the remaining 8 patients, there were 12 NMOSD-related pregnancies. NMOSD onset occurred in 5 patients during pregnancy or within 6 months postpartum. For the other 7 pregnancies (in 5 patients) that occurred after NMOSD onset, there were 8 relapses - 2 during pregnancy, and 6 at 0-3 months postpartum. Of note, after disease onset, all subsequent pregnancies were associated with relapses. 90[percnt] postpartum relapses/onset occurred during 0-3 months postpartum. Mean annualized relapse rate (ARR) was 0.43 before pregnancy, and it rose significantly to 3.43 at 0-3 months postpartum (pu003c0.05). Also, unlike MS, ARR was not reduced during pregnancy. Interestingly, all children being born were healthy, and none developed NMOSD. CONCLUSIONS: Pregnancy adversely affects the disease course of AQP4+ NMOSD, with 0-3 months postpartum posing high risk for relapse/onset attack. Without appropriate treatment, relapse rate is high. An international NMOSD pregnancy registry may be useful to identify the suitable preventive therapies during pregnancy and postpartum period. It is also worthwhile to investigate further the Th1/Th2 shift/balance during pregnancy and postpartum, and for factors leading to NMOSD onset/relapse. Disclosure: Dr. Hor has nothing to disclose. Dr. Chow has nothing to disclose. Dr. Lim has nothing to disclose. Dr. Chia has nothing to disclose. Dr. Tan has nothing to disclose. Dr. Cheah has nothing to disclose. Dr. Ching has nothing to disclose. Dr. Arip has nothing to disclose. Dr. Easaw has nothing to disclose. Dr. Eow has nothing to disclose.