Historically media campaigns and educational materials for diverse groups have been part of actions for the prevention of Aids and other sexually transmitted infections (STI). Informed by the criticism regarding the use of the informational communication model in these communicative strategies, the article analyses STI/Aids prevention’s messages in 14 educational materials aimed at pregnant women, produced between 1995-2017 in Brazil. Elements of the production context were identified and the enunciation device of these materials was examined. According to the findings, the materials reiterate prenatal testing as a woman’s responsibility. Information on condom use during pregnancy, the role of the partner in prevention and the perspective of comprehensiveness in health care are scarce. The results point to the need to develop communication actions for women that include sociocultural factors (social class, race, gender norms) which condition vulnerability to HIV/Aids and Syphilis.