Former nurse Stephanie Greene, 39, was convicted in Spartanburg on Thursday (local time) of homicide by child abuse, involuntary manslaughter and unlawful neglect of a child.
"This is not an indictment on breast feeding," said Barry Barnette, solicitor for the 7th Judicial Circuit. "She loved her drugs more than she loved her baby."
Greene went to several doctors to obtain morphine and other painkillers in 2010, but told none of them she was pregnant, prosecutors said.
Toxicology tests on her 6-week-old daughter, Alexis, in November 2010 revealed a lethal amount of morphine and the presence of at least three other drugs in the baby's system, Barnette said.
Greene's defence argued that not enough of the drugs could have passed through her breast milk to kill the baby, but no other evidence for the child's death existed, according to the prosecutor.
A medical expert testified that a child receiving an overdose of morphine would not gain weight. When Greene's baby died, she weighed only four ounces more than her birth weight.
"It fit the pattern," Barnette said. "She's a nurse. She knew the dangers."
Greene faced a possible life sentence and must serve at least 16 years in prison under South Carolina law.
She still faces 38 charges of fraudulently obtaining drugs, Barnette said.
