Pregnant women constitute a risk group for any infection due to their low immunity condition. This is a descriptive study with a qualitative approach, grounded in the Theory of Social Representations that sought to understand the reasons why pregnant women did not vaccinate against influenza A (H1N1). The study included 10 women who were pregnant during the vaccination campaign of 2010. Data were collected in May 2011 through interviews and interpreted by content analysis. From the speeches it was possible to identify the various representations that the vaccine against H1N1 had for these women during their pregnancy as an element which would cause miscarriage and birth defects. The reasons why pregnant women did not vaccinate against H1N1 are associated with fear, lack of information and the myths and beliefs that people bring in their representations and their cultural values.