Doctors had predicted she would at most only survive for days after her birth. The girl died at Maine Medical Center on Friday afternoon, hospital spokesman John Lamb said. She had been hospitalized in critical condition for nearly a week.
Being born with "mermaid syndrome," also known as sirenomelia, meant that the Kennebunkport girl had only one partially working kidney, no lower colon or genital organs and legs fused from the waist down.
Some children who have survived sirenomelia have had surgery to separate their legs, but Shiloh did not because blood vessels crossing from side to side in her circulatory system would have been severed. She had received two kidney transplants, the last one in 2007.
Her story was featured recently on "The Oprah Winfrey Show" and other national television programs.
Earlier this month, her mother, Leslie Pepin, said her daughter came down with a cold that quickly turned to pneumonia. Shiloh was rushed to Maine Medical Center on Oct. 10 and was placed on antibiotics and a ventilator.
For a while, Leslie Pepin said, things were looking up. "She's a tough little thing," she said of her daughter earlier this week.
Shiloh was a fifth-grader at Kennebunkport Consolidated School. "She was such a shining personality in that building," said Maureen King, chairwoman of the board of the regional school district. Counselors will be available next week to talk to students.
Through the television shows, news articles, Facebook and other Web sites, Shiloh inspired many.
"I live in Iowa. I have cerebral palsy. I love your video," 12-year-old Lydia Dawley wrote to Shiloh on Facebook. "You have a great personality I wish you lived close so we could be friends and hang out. You opened my eyes because you are so brave."