OBJECTIVES: To identify and describe the doubts and difficulties of pregnant and postpartum women regarding breastfeeding. CASE REPORT: This cross-sectional descriptive study included 116 women, 36 pregnant and 80 postpartum, and was approved by the CEP/Santa Casa (Nº 23355). A questionnaire was generated that comprised questions about breastfeeding and was submitted to the study groups. The variables were analyzed through associations between the responses of the groups with the chi-square, Fisher's exact, and Student's t tests. Mothers had higher knowledge scores overall about breastfeeding than pregnant women (p = 0.001). The main concerns reported by women were in relation to milk production (11%), postpartum colostrum (11%), and milk secretion during pregnancy (8.3%). In the puerperal group, the most frequent complaints were in relation to latching on (27.6%), breast pain (27.6%), and mammary fissure (13.8%). In addition, considering the influence of age, there was a significant positive association between age and percentage of puerperal knowledge (p = 0.011). Besides maternal inexperience, primiparous women had more complaints than women with one or more child (p = 0.014). CONCLUSIONS: Pregnant women, primiparous women, and teenage and young women have more doubts and difficulties in relation to breastfeeding. An intervention strategy by a treatment team is warranted to educate women about breastfeeding and to address doubts and difficulties.