A South Carolina woman was sentenced to 20 years in prison for killing her 6-week-old baby with what prosecutors say was an overdose of narcotics delivered through her breast milk.

The convicted woman is 39 year-old Stephanie Greene who was found guilty of homicide by child abuse, involuntary manslaughter, and unlawful conduct towards a child on Thursday. On Friday, Greene was sentenced to 20 years in prison.

Surprisingly enough, this isn't the first time Greene has neglected a child or been convicted of a crime. Greene is a former nurse who lost her nursing license in 2003 after being convicted for her attempt to obtain drugs illegally.  

She also lost custody of her two older children in 2003 after being convicted of child negligence, according to South Carolina's 7th Judicial Circuit Solicitor, Barry Barnette.

In the case of her 46-day-old baby, prosecutors say that, because Greene was a nurse, she knew the dangers of consuming painkillers while pregnant.

"According to the U.S. Food and Drug Administration, mothers taking morphine or codeine drugs while breastfeeding should do so with extreme caution because their babies could overdose," ABC News reports.

To maintain her drug habit, Greene hid her pregnancy from two doctors who prescribed her drugs for pain she suffered from a 1988 car accident. Neither doctor was aware of the amount of drugs she was taking at the time.

Greene's husband also enabled her drug habit. When the former nurse could no longer hide her baby bump from doctors, Greene began missing her doctor's appointment and sent her husband to pick up her prescriptions instead.

As Greene continued to consume heavy levels of morphine while breastfeeding, her 46-day-old daughter Alexis Greene's body could no longer keep up. On Nov. 13, 2010, Alexis Greene was pronounced dead.

During the investigation of Alexis's death, tests revealed toxic levels of morphine and Klonopin in her blood. Records also showed that Greene's baby lost nearly half a pound in the month before she died due to the morphine overdose.

Greene showed no emotion upon receiving her 20-year sentencing on Friday, according to Barnette.