Background Multiple sclerosis is a chronic disease of the central nervous System.Most women with MS are diagnosed during their reproductive ages.This study evaluated the effect of pregnancy on MS and the effect of MS disease on fertility and pregnancy health. Material & methods: A retrospective descriptive-analytic study was conducted on 110 women suffering from MS with a history of pregnancy(between 2007 and 2017years) in Isfahan, Iran.Samples were selected in a census model.Women completed a researcher-constructed questionnaire by telephone.The questionnaire consisted of three parts: demographic information,MS and its symptoms and its treatment, and the third part was related to the reproductive system and the history of pregnancy associated with MS. Data were analyzed by SPSS software version 16 using Chi-square, ANOVA and t-test.Results The mean age of women with MS was 32.4 years.The most common primary symptom was blurred vision(42.7%).In this population,the average number of pregnancies was 1.61,the number of deliveries was 1.35,the number of abortions was 0.24,the history of ectopic pregnancy was 0.01,the number of alive children was 1.36 and the number of dead children was 0.01.The average time of the last MS attack before the pregnancy was 21.36 months. Fatigue(24.5%) was the most common symptom exacerbated during pregnancy. MS symptoms improved in55.0% of subjects in the second trimester.Discussion MS had no effect on the pregnancy status, such as the number of abortions,ectopic pregnancy, alive and dead children and the duration of pregnancy.The symptoms of the disease are improved during pregnancy.Therefore, pregnancy has a protective role against MS.