Background:The World Health Organization recommends that infants should be exclusively breastfed until the age of 6 months. The aim of this study was to assess the ratio of breastfeeding patients with Rheumatic Diseases (RD) and to identify possible causes of its discontinuation.Objectives:The aim of this study was to assess the ratio of breastfeeding patients with Rheumatic Diseases (RD) and to identify possible causes of its discontinuation.Methods:This study was embedded in the P-RHEUM.it register, as a nationwide prospective cohort study collecting data of pregnancies in inflammatory RD. Pregnancies, enrolled until the 20th week of pregnancy, are followed from pregnancy until 6 months postpartum. At baseline, sociodemographic parameters, obstetric history, comorbidities are reported. During pregnancy, the course of maternal disease, development of foetus and complications are reported. After delivery, the pregnancy outcome, data on lactation and child development are collected.Results:From May 2018 to May 2020 data of 349 patients were available. Data on lactation were available in 44 pregnancies. Two months after delivery 37 were continuing breastfeeding (n=26) or mixed feeding (n=11), while 7 were using formula feeding. Among patients using formula feeding 2 had a diagnosis of rheumatoid arthritis (RA), 1 of juvenile idiopathic arthritis, 1 of undifferentiated arthritis (UA), 1 of anti-phospholipid syndrome (APS), 1 of vasculitis and 1 of systemic lupus erythematosus. The reasons of formula feeding were the following: 2 for agalactia, 2 for personal preferences, 3 for drug-related concerns (1 for physician’s decision in a patient with APS; 2 for maternal concerns about drugs in patients with RA and UA treated respectively with Adalimumab and Tocilizumab). At 6 months 30 continued breastfeeding (n=23) or mixed feeding (n=7) and 14 formula feeding. The reasons of formula feeding were available in 9 patients: 3 for agalactia, 2 for personal preferences, 2 for physician’s decision in a patient with APS and in a patient positive for anti-phospholipid antibodies; 2 for maternal concerns about drugs.Conclusion:Preliminary data of this prospective study demonstrate a high percentage of breastfeeding/mixed feeding after delivery and after 6 months among women with RD. Drug related concerns are the main reason of discontinuation of breastfeeding, although medication results compatible with lactation. Using our results, strategies supporting patients with RD whishing to breastfeed may be developed.References:[1]Carina Gotestam Sporken et al. The EULAR points to consider for use of antirheumatic drugs before pregnancy, and during pregnancy and lactation. Ann Rheum Dis 2016.[2]Sammaritano et al. 2020 American College of Rheumatology Guideline for the management of reproductive health in rheumatic and muscoloskeletal diseases, Arthritis Rheumatol. 2020.Acknowledgements:Authors would like to thank SIR study center and all patients who accepted to partecipate to our studyDisclosure of Interests:None declared