Pregnancy has a detrimental effect on the disease course in neuromyelitis optica spectrum disorder (NMOSD), found a new study published in the Annals of Clinical and Translational Neurology.

“The postpartum period is a particularly high-risk time for the onset and relapse of NMOSD,” the researchers wrote. They also said immunotherapy may be recommended during pregnancy and right after to reduce the risk of pregnancy related NMOSD attacks.

To explore the effect of pregnancy on the disease course and identify the independent predictors of pregnancy related NMOSD attacks, a team of researchers from China led by Hongyu Zhou from the Department of Neurology, West China Hospital, Sichuan University, Guo Xuexiang in Chengdu conducted a retrospective study in 112 women with NMOSD who reported 202 pregnancies following the onset of NMOSD symptoms.

Continue Reading

Read more about the treatment of NMOSD

The researchers compared the annualized relapse rate of NMOSD in the women before, during, and after pregnancy. They also assessed their degree of disability, using the Expanded Disability Status Scale (EDSS) score.

The results showed that the annualized relapse rate in the first-trimester following delivery was higher compared to before and during pregnancy.

Moreover, the women’s EDSS score increased from a median of 1.4 before pregnancy to a median of 1.99 after delivery. 

The researchers identified risk factors that predicted pregnancy-related attacks as higher disease activity 1 year before conception and lack of immunotherapy during pregnancy and after delivery.

“Larger-scale prospective studies are warranted to confirm our findings,” they wrote. 

NMOSD is a rare autoimmune disease affecting the central nervous system characterized by recurrent optic neuritis. The disease mostly affects women, but the exact cause of this is not known. There may be genetic and environmental factors that trigger the development of the disease.


Du Q, Shi Z, Chen H, et al. Effects of pregnancy on neuromyelitis optica spectrum disorder and predictors of related attacks. Ann Clin Transl Neurol. Published online October 31, 2022. doi:10.1002/acn3.51683