High risk of postpartum relapses in neuromyelitis optica spectrum disorder.

OBJECTIVE

To study the effect of pregnancy on the frequency of neuromyelitis optica spectrum disorder (NMOSD) relapse and evaluate rates of pregnancy-related complications in an international multicenter setting.

METHODS

We administered a standardized survey to 217 women with NMOSD from 7 medical centers and reviewed their medical records. We compared the annualized relapse rate (ARR) during a baseline period 2 years prior to a participant's first pregnancy to that during pregnancy and to the 9 months postpartum. We also assessed pregnancy-related complications.

RESULTS

There were 46 informative pregnancies following symptom onset in 31 women with NMOSD. Compared to baseline (0.17), ARR was increased both during pregnancy (0.44; = 0.035) and during the postpartum period (0.69; = 0.009). The highest ARR occurred during the first 3 months postpartum (ARR 1.33). A total of 8 of 76 (10.5%) with onset of NMOSD prior to age 40 experienced their initial symptom during the 3 months postpartum, 2.9 times higher than expected.

CONCLUSIONS

The postpartum period is a particularly high-risk time for initial presentation of NMOSD. In contrast to published observations in multiple sclerosis, in neuromyelitis optica, relapse rate during pregnancy was also increased, although to a lesser extent than after delivery.