Objective To determine the prevalence of sexual dysfunction and its associated factors in pregnant women. Methods A descriptive, cross-sectional study including 262 pregnant women aged 18years or older with gestational age between 10 and 35weeks. Women with urinary tract infections and conditions of gestational risk were excluded. The Pregnancy Sexual Response Inventory (PSRI) questionnaire was used. We performed a univariate descriptive analysis, and comparisons between the mean values of the sexual function domains were made using the Student t -test. The chi-squared test was used to determine the association between the independent and dependent variables. The prevalence ratios, with their respective 95% confidence intervals, were also estimated, and a multivariate analysis was performed. Results A total of 64.9% of women reported a decrease in the frequency of sexual activity during pregnancy. Slightly more than half of the women (50.8%) were satisfied, and arousal was reported as excellent/good by 30.5% of them. The frequency of sexual difficulties/dysfunctions increased with pregnancy, rising from 5.7% to 58.8%, and pain during sexual intercourse was reported by 45.8% of them. Having higher education degree decreased the chance of being sexually dissatisfied by 50%. The total PSRI score showed a significant decrease from the prepregnancy period (mean score=89.8, excellent) to the pregnancy period (mean score=59.2, good). Conclusion The mean sexual function score during pregnancy was classified as good, although most pregnant women reported at least one type of alteration in the sexual function domains, and the report of dissatisfaction was more frequent in women with lower schooling. Resumo Objetivo Determinar a prevalencia e fatores associados de disfuncAo sexual em gestantes. Metodos Estudo descritivo, transversal, incluindo 262 gestantes com idade de 18 anos ou mais, e idade gestacional entre 10 e 35 semanas. Mulheres com infeccAo de trato urinario e gestacAo de alto risco foram excluidas. O Inventario de Resposta Sexual na GestacAo (Pregnancy Sexual Response Inventory, PSRI) foi utilizado. Procedeu-se a analise univariada, e as comparacoes entre as medias dos dominios de funcAo sexual foram avaliadas pelo teste t de Student. Associacoes entre as variaveis dependentes e independentes foram determinadas por teste do qui-quadrado. Tambem estimou-se a razAo de prevalencia, com intervalo de confianca de 95%, e realizou-se analise multivariada. Resultados Um total de 64,9% das mulheres relataram diminuicAo na frequencia de atividade sexual durante a gravidez. Pouco mais da metade das mulheres (50,8%) estavam satisfeitas, e a excitacAo foi relatada como excelente/boa por 30,5% delas. A frequencia de dificuldades/disfuncoes sexuais aumentou com a gravidez, subindo de 5,7% para 58,8%, e dor na relacAo sexual foi relatada por 45,8% delas. Ter Ensino Superior diminuiu em 50% a chance de insatisfacAo sexual. O escore total do PSRI diminuiu significativamente entre o periodo pre-gestacional (escore medio=89,8, excelente) e o periodo gestacional (escore medio=59,2, bom). ConclusAo O escore medio da funcAo sexual durante a gestacAo foi classificado como bom, embora a maioria das gestantes tenha relatado pelo menos um tipo de alteracAo nos dominios da funcAo sexual. O relato de insatisfacAo foi mais frequente nas mulheres de baixa escolaridade.