The smallest of four babies born to a 55-year-old woman has died after being taken off life-support machines, the San Diego Union Tribune reported Tuesday.

The quadruplets were born almost three months premature to a single woman through the help of fertility treatments. A girl who weighed only 10 1/2 ounces died Sunday after physicians told the mother there was no chance the baby could survive on her own, the newspaper said.The girl was known only by a letter - Baby D. She was a victim of renal insufficiency and cerebral bleeding brought on by her premature birth. Her brother and two sisters remained in critical condition, sources told the newspaper.