Summary Introduction. Dengue is the most important mosquito-borne viral disease. The World Health Organization in 1994 estimated that 2.000 million people worldwide are exposed to contagion. This study aimed to characterize dengue virus (DV) infection in pregnant women with or without acute febrile syndrome and the impact on their newborns (NB). Methods: Blood samples were collected from the binomial mother -NB for hematological analysis and specific diagnosis by qPCR -DV -DV - NS5, NS1 antigen and IgM / IgG antiDV. Results: 30 pregnant women (14-36 years old) attending the Obstetric Emergency of Instituto Autonomo Hospital Universitario de Los Andes between June 2010 and July 2011 were included. Twenty six percent of mothers were suspected dengue cases and 73.3 % were not. Twenty three percent of pregnant women were reactive to IgM - antiDV, 6 of 8 suspected dengue patients and 1 of 22 non suspected. One of 7 infected mothers presented with nonspecific symptoms, 4 with fever, chills, myalgia, arthralgia , nasal congestion, jaundice and retro -ocular pain, and 2 with signs of shock characterized by severe genital bleeding and hypovolemic shock. Vertical transmission occurred in 2/7 NB of mothers with dengue shock. These NB presented with fetal distress, with thrombocytopenia and mild jaundice as the predominant findings. IgG antibodies were detected in 9/30 pregnant mothers and their NB, suggesting secondary infection. Conclusions: In endemic and epidemic areas DV infection occurs transplacentally during the peri -partum period. The effects of infection in pregnant women and newborns were characterized in this study.