Routine vaccination is part of the pediatrics universe. In adulthood and particularly when women voluntarily access to medical care, immunization should be reviewed and updated. There are many doubts that generate in all health professionals anxiety and concern about the vaccination of a pregnant woman. This article aims to describe the immunological changes in pregnant women, to clarify the purpose of immunization during pregnancy, and to enumerate indications, contraindications and risks of vaccines of the Portuguese National Vaccine Plane and other vaccines against diseases with prevalence in other countries. Due to the medical and social impact of vaccination against seasonal influenza and influenza A (H1N1) in the winter of 2009, during an influenza (H1N1) pandemic flu, we make reference to the indications and vaccination against these infections in pregnancy.