Introduction: The influence of breastfeeding and it & PRIME;s duration on the course of multiple sclerosis (MS) is unclear. Here we analyzed a real-world data for breastfeeding women with MS and their disease course collected from a Czech national registry ReMuS.Objectives: To identify risk factors associated with not initiating breastfeeding after delivery, to analyze the impact of breastfeeding on the MS disease course, evaluate the assumption, that breastfeeding is not harmful in MS patients, and compare the disease course by breastfeeding status.Materials and methods: Using propensity score matching we compared Expanded Disability Status Scale (EDSS), confirmed disease worsening (CDW) and annual relapse rate (ARR) in breastfeeding and non-breastfeeding MS patients according to disease duration, disease modifying treatment (DMT) before pregnancy, last EDSS score before conception, age, and ARR during pregnancy. We also compared these parameters between breastfeeding patients not using a DMT and non-breastfeeding patients who resumed DMT within 3 months after delivery. EDSS, ARR, and CDW were collected at 12, 24, and 36 months after delivery.Results: A total of 1681 pregnancies that ended in delivery were analyzed from 2013 through 2020. Change in ARR and EDSS values and 6-months CDW did not significantly differ between the analyzed groups. Compared with non-breastfeeding women who resumed DMT early after delivery, breastfeeding women with MS did not experience worse clinical outcomes even without initiating a DMT. Discussion: Breastfeeding in Czech women with MS did not negatively affect the disease course and can be supported. Patients with MS can be treated with certain DMTs alongside breastfeeding and there is no need to stop breastfeeding, if the patient is clinically stable.