ABSTRACTBACKGROUND:The Pregnancy Mobility Index (PMI) was developed to assess mobility in pregnant women in the Netherlands. At present, no similar questionnaire is available in Brazil.OBJECTIVE:The present study aimed to translate, cross-culturally adapt, and evaluate the psychometric properties of a Brazilian PMI.DESIGN AND SETTING:The present study was a validation study conducted at the Universidade Federal do Paraná and a public maternity ward in Curitiba, Brazil.METHODS:Text translation and cross-cultural adaptation followed international guidelines. Construct validity, internal consistency, and inter- and intra-rater reliability tests included 97 women. The Pelvic Girdle Questionnaire, Multidimensional Pain Evaluation Scale, Schober’s test, and lumbar spine range of motion assessment were administered on the first day. Intra-rater reliability (n = 19) was measured after 15 days. Exploratory factor analysis was performed, and the correlation matrix was analyzed using Pearson’s coefficient.RESULTS:Pregnant women (88%) understood the cultural adaptation process. The internal consistency was high (Cronbach’s alpha > 0.90), construct validity was moderate, with significant correlation between lumbar spine range of motion (r = 0.283–0.369) and Schober’s test (r = -0.314), and high correlation between the Multidimensional Pain Evaluation Scale (r = -0.650 and -0.499) and Pelvic Girdle Questionnaire (r = -0.737). Intra- and inter-rater reliabilities were excellent (intraclass correlation coefficient = 0.932 and 0.990, respectively).CONCLUSION:The Brazilian version of the PMI was successfully translated with excellent reliability and moderate-to-high construct validity. It is an important tool for assessing mobility in pregnant women.CLINICAL TRIAL:RBR-789tps (Validation study),https://ensaiosclinicos.gov.br/rg/RBR-789tps.