OBJECTIVE: To describe trends in sociodemographic, immunological and virological profiles and interventions to decrease the risk of mother-to-child HIV transmission. METHODS: Retrospective cohort study conducted at a tertiary institution in Rio de Janeiro, Brazil from January 1996 to December 2004. Analysis was performed by stratification in three time periods: 1996-1998 (P1), 1999-2001 (P2) and 2002-2004 (P3)....