In Aztec society, the noble caste was peopled with those of privilege, who were charged with ruling and protecting those below them. Just as with the commoners, however, the upper class could not escape the troubles of life. For the noblewoman, the problems associated with pregnancy were the same as those faced by all. Personifying the fear of death during childbirth was the civatateo - the vengeful spirits of noblewomen who died while in labor.
Caught in a state between life and death, these vampires (called 'civapipiltin' or 'princess') no longer served the people, but the moon deities, Tezcatlipoca and Tlazolteotl. They lived in Tamoanchan, and were said to have had the magical powers of a priest. In their priestly role, they were responsible for the safe nightly delivery of the setting sun to the afterworld of the west.
However, on certain days, they were said to return to earth, where they stalked travelers at crossroads and lurked in temples. The Aztecs blamed the civatateo for plaguing men with uncontrollable lust and children with epilepsy. These hideous creatures were terrifying to look upon. Sometimes appearing as desiccated birds, they are most often described as shriveled old hags, whose tattered clothes were covered with glyphs. The exposed skin of their face, arms and hands was a deathly white, covered with a chalky substance called ticitl.
Selected Sources:
http://members.dencity.com/MythicalCreatures/
http://www.pantheon.org/
http://www.sacrosanctum.org/