Effects of pregnancy on neuromyelitis optica spectrum disorder and predictors of related attacks

OBJECTIVE: Our study aimed to investigate the influence of pregnancy on the course of neuromyelitis optica spectrum disorders (NMOSD) and to explore the independent predictors of pregnancy‐related attacks. METHODS: We performed a retrospective study of patients with NMOSD based on the Wingerchuk 2006 or the revised Wingerchuk 2015 criteria. Demographic, clinical, and pregnancy data were recorded. We compared the annualized relapse rate (ARR) before, during, and after pregnancy. The Expanded Disability Status Scale (EDSS) score was used to assess the degree of disability. Multivariate Cox proportional hazards models were used to identify the independent risk factors that predict pregnancy‐related attacks. RESULTS: There were 202 informative pregnancies following symptom onset in 112 women with NMOSD. The ARR in the first‐trimester postpartum period (1.44 ± 2.04) was higher than that before pregnancy (0.23 ± 0.48; p < 0.001) and during pregnancy. The EDSS score increased from 1.40 ± 1.38 before pregnancy to 1.99 ± 1.78 postpartum (p = 0.004). Multivariate Cox proportional hazards models indicated that increased disease activity 1 year before conception (HR = 1.79, 95% CI 1.09–2.92, p = 0.021) and lack of immunotherapy during pregnancy and the postpartum period (HR = 5.25, 95% CI 1.91–14.42, p = 0.001) were independent risk factors that predicted pregnancy‐related attacks. INTERPRETATION: The postpartum period is a particularly high‐risk time for the onset and relapse of NMOSD. Pregnancy exerted detrimental effects on the disease courses of NMOSD. Immunotherapy during pregnancy and the postpartum period might be recommended to decrease the risk of pregnancy‐related attacks. Larger‐scale prospective studies are warranted to confirm our findings.