 Portillo's films generally focus on Latin America and the experience of Latin American-born immigrants in the United States.Her film debut, the 1979 "Después del Terremoto", focuses on the experience of a Nicaraguan refugee of the 1972 Managua earthquake in San Francisco.It was followed by "The Mothers of Plaza de Mayo", a 1986 co-production with the Argentine director Susana Blaustein Muñoz which documented the actions of Mothers of the Plaza de Mayo, a group of Argentine women who gather weekly at the Plaza de Mayo in Buenos Aires to remember their children that were murdered or "disappeared" by the military regime.