Gender issues and the female preponderance in neuromyelitis optica spectrum disorder (NMOSD) have been investigated before, yet the interplay between NMOSD and menstrual characteristics has remained unknown. Thus, the aim was to compare menstrual cycle patterns and their symptoms in NMOSD patients and healthy women.

This cross-sectional study was conducted during 2015–2016 in Isfahan, Iran, and included female patients aged>14years with a diagnosis of NMOSD and healthy subjects as controls. Data regarding age at menarche, menstrual characteristics, history of premenstrual syndrome (PMS) and possible perimenstrual symptoms were collected. Also, NMOSD patients were asked to report changes in their menstrual cycles after onset of the disorder.

The final study population included 32 NMOSD and 33 healthy controls. These groups did not differ regarding their demographics (P>0.05), and age at menarche in the NMOSD and control groups was 13.31±1.49 years and 13.48±1.44 years, respectively (P=0.637). The controls experienced PMS more frequently (78.8% vs. 40.6% in the NMOSD patients; P=0.03), with no significant differences in other menstrual features between groups (P>0.05). However, changes in menstruation after NMOSD onset were reported by 43.8% of patients, with an increase in menstrual irregularities from 15.6% to 43.7% (P=0.012); other menstrual characteristics did not differ after disease onset (P>0.05).

Menstruation do not differ between healthy controls and NMOSD patients before the onset of disease whereas, after its onset, those affected experienced more irregularities in their menstrual cycles. This may be an effect of NMOSD and its underlying disorders on menstruation and suggests that further interventions may be required for affected women.