The risk of dengue virus infection during pregnancy has increased due to the current rash of frequent and severe dengue epidemics. The effects of dengue virus in the fetus and newborn children have been studied only superficially and with contradictory results. Therefore, a retrospective cohort study was conducted in Medellin, Colombia, to describe the fetal and postnatal effects of dengue virus infection acquired during pregnancy. Twenty-two babies born from mothers who suffered dengue during the epidemics of 1998 were compared with babies from non-infected mothers. In the exposed cohort, three premature births occurred, three children suffered from fetal anomalies and four children were born with low weight. In the non-exposed children, none of these problems were found. Psychomotor development was normal in both groups. Only the low weight subgroup was statistically significant (Fisher test, p = 0.045). These results suggested that the children from women with dengue during pregnancy present low weight, greater frequency of premature birth and increased fetal distress. A larger sample is necessary to confirm these results.