RT Journal Article SR Electronic T1 The interplay of multiple sclerosis and menstrual cycle: which one affects the other one? (P4.355) JF Neurology JO Neurology FD Lippincott Williams & Wilkins SP P4.355 VO 90 IS 15 Supplement A1 Omid Mimosayyeb A1 Shervin Badihian A1 Navid Manouchehri A1 Vahid Shaygannejad YR 2018 UL http://n.neurology.org/content/90/15_Supplement/P4.355.abstract AB Objective: Here, we aimed to compare the pattern of menstrual cycle and its symptoms between MS patients and healthy controls.Background: Menstruation is suggested to affect multiple sclerosis (MS) symptoms, while the effect of MS on menstruation is not studied before. Some reports have shown deterioration of MS symptoms in the premenstrual period, while there are results against this finding.Design/Methods: This is a cross-sectional study conducted during 2015–2016 in MS clinic of Kashani hospital, Isfahan, Iran. We included female patients >14 years with diagnosis of relapsing-remitting MS, and healthy subjects as the control group. We collected data regarding menarche age, menstrual habits, history of premenstrual syndrome, the amount of menstrual bleeding, and the possible symptoms of menstruation from all subjects. Also, MS patients were asked to report changes in menstrual habits after MS occurrence.Results: The final study population contained 181 MS patients and 202 healthy subjects. The mean age in MS and control group were 36.04±9.86 and 35.16±11.30, respectively (P-value=0.426). Menarche age in MS patients and control group were not statistically different (13.59±1.87and 13.29±1.53, respectively; P-value=0.087). Changing menstrual habits was reported in 44 MS patients (38.6%). Irregular menstrual cycle increased from 21.3% to 40.4% after occurrence of MS (P-value<0.001). Almost all menstrual symptoms were reported more frequently by MS patients before, during, and after menstrual period (P-values<0.001).Conclusions: We found no difference regarding menstrual habits in MS patients before onset of the disease and healthy controls. Irregular menstrual cycle was observed more after the disease occurrence while other menstrual habits did not change. Moreover, almost all menstrual symptoms were reported more frequently by MS patients during the period.Disclosure: Dr. Mimosayyeb has received research support from Isfahan Neurosciences Research Center; Alzahra Research Institute; Isfahan University of Medical Sci. Dr. Badihian has nothing to disclose. Dr. Manouchehri has nothing to disclose. Dr. Shaygan Nejad has nothing to disclose.