Spontaneous Recovery of Neuromyelitis Optica Spectrum Disorder during Pregnancy

Neuromyelitis optica spectrum disorder (NMO-SD) is an autoimmune inflammatory disorder associated with the anti-aquaporin-4 (AQP4) antibody. Over 90% of NMO-SD patients have poor prognosis, and pregnancy is a disease-worsening factor. The authors report the findings in a case of NMO-SD that recovered spontaneously during pregnancy. A 28-years-old woman developed optic neuritis (ON) of the right eye in the 14th week of pregnancy. Her best-correlated visual acuity (BCVA) was 0.02 OD, the critical flicker frequency (CFF) was not measurable, and the mean deviation (MD) of the Humphrey perimetry 30-2 was -42 dB. Magnetic resonance imaging (MRI; T2 short-tau inversion recovery [STIR]) showed high-intensity right optic nerve. The patient was diagnosed with NMO-SD by the detection of seropositive anti-AQP4 antibody in her serum. Corticosteroid pulse therapy was considered, but the patient declined any treatment. Two weeks later, her BCVA improved to 1.2 (OD). Nine weeks later, the MD of Humphrey perimetry 30-2 improved to -1.2 dB and the CFF was 39.8 Hz. There have been no signs of recurrence for 6 months. Spontaneously recovered cases of NMO-SD during pregnancy are very rare. Although the factors leading to good outcomes have not been identified, this case suggests that the immunological condition at the early stage of the pregnancy may have different from that at later stages. Further studies are needed to identify the relationship between pregnancy and NMO-SD.