Pregnancy Outcomes in Neuromyelitis Optica Spectrum Disorder

A recently published study looked at pregnancy outcomes in individuals with aquaporin-4-positive (AQP4) neuromyelitis optica spectrum disorder (NMOSD). Studying pregnancy in NMOSD is important because NMOSD is more common in women and often occurs during childbearing years.

60 women with a history of at least one pregnancy who had AQP4-positive NMOSD from three countries (UK, Portugal, and Japan) were enrolled in the study. The researchers looked at pregnancy outcomes, including miscarriage and preeclampsia. Miscarriage was defined as a spontaneous loss of pregnancy during the first 24 weeks of pregnancy. Preeclampsia occurs when there is high blood pressure in pregnancy and protein in urine.

NMOSD disease onset occurred at an average age of 46.4 years. Onset was with optic neuritis in 42% of the women, transverse myelitis in 38% of the women, and brain lesions in 18% of the women.

The study included data from 85 pregnancies from 40 women in the miscarriage part of the study. 71 pregnancies occurred before NMOSD onset and 14 pregnancies occurred after NMOSD onset. Eleven pregnancies in total (12.9%) in 6 women ended in miscarriage, which is not different from the miscarriage rate in the general population.

In this study, the miscarriage rate was found to be higher after the onset of NMOSD (42.9%) than before NMOSD onset (7.04%). There was also an increased odds of miscarriage in pregnancies after or in the three years before the onset of NMOSD, even when controlling for older maternal age and miscarriage in the most recent pregnancy. The miscarriage rate also differed by race: the miscarriage rate after NMOSD onset was 60% in Caucasian women and 0% in Afro-Caribbean women. The NMOSD relapse rate in the preconception and intrapregnancy period was higher in pregnancies that ended in miscarriage compared with pregnancies that did not end in miscarriage after NMOSD onset. These women were also more likely to be receiving treatment for NMOSD, but the miscarriages were not from the medication. These women had more attacks which made them more likely to be receiving treatment.

The study included data from 113 pregnancies from 57 women in the preeclampsia part of the study. 13 cases (11.5%) of preeclampsia occurred. NMOSD onset was not a risk factor for preeclampsia, although the rate of preeclampsia was higher in the study participants than in the overall population. In particular, the study reported that the odds of preeclampsia were greater in women who had multiple other autoimmune conditions or who had had a miscarriage in their most recent pregnancy.

Annualized relapse rates (ARR) were also calculated. Pregnancies that didn’t end in miscarriage were associated with a significantly increased average ARR in the first 3 months after birth compared with the average ARR up to 9 months before conception.

The authors state that it is possible that AQP4 can contribute to miscarriage risk because of the results of this study and other studies done on animals, but they state that further studies are needed in this population. It also appears as though some women were prone to miscarriage in this study. Of note, in this study, the number of women TREATED before and during pregnancy were too small to determine if the rates of miscarriage could be lowered by using treatment. As a result, the data set in this study is too small to base decisions on, but should be taken into account when consulting with a neurologist about pregnancy planning.

Nour MM, Nakashima I, Coutinho E et al. Pregnancy outcomes in aquaporin-4-positive neuromyelitis optica spectrum disorder. Neurology. 2015;86(1):79-87.