Despite showing in recent decades a decrease in its prevalence, Chagas remains one of the most important endemic diseases in Argentina. The epidemiological dynamics of Chagas has undergone remarkable changes. The urbanization of this traditionally rural disease, together with the decrease in vectorial contagion has made vertical the main form of transmission nowadays. This new scenario places women in reproductive age-and more so those living in urban areas-at the center of the scene. It becomes then necessary to revise and expand the epidemiological knowledge about Chagas, in order to contribute to the reorientation of practices, policies and health management processes. The aim of this study was to report the trend of Chagas seroprevalence in pregnant women served at the public health system of Buenos Aires City between 2003 and 2015, to describe the clinical and socio-demographic characteristics of this group and to characterize the information systems used. The methodology used was time series analysis. The data sources were the Neonatal Screening Program of the city of Buenos Aires (PPN), the Perinatal Information System (SIP) and the Module of Laboratory Surveillance of the National Surveillance System of the National Ministry of Health (SIVILA). The results showed a downward trend in the prevalence of Chagas in pregnant women between 2003 and 2015, with a mean of 2,58%. A statistically significant association was found between having Chagas and being over twenty years old, being multiparous and having no formal studies. The information systems used showed heterogeneity in terms of the information they handle, the period included and the record's range of coverage. The SIVILA, which emerged as an attempt to articulate other information systems, is just beginning to be implemented in the city of Buenos Aires.