A Montgomery County woman was sentenced Thursday to five to 10 years in prison for injecting her 15-year-old daughter with heroin.

Patricia Davenport gave her daughter the drug to snort in their Harleysville home, drove her to Philadelphia to buy drugs, and injected the girl and the girl's boyfriend with heroin, prosecutors said.

"Sure, you gave me shelter and food and most basic necessities," the daughter wrote in a letter read by a victim advocate at the sentencing hearing in Norristown. "But you also gave me heroin."

Davenport's actions were "unimaginable," said Assistant District Attorney Kathleen McLaughlin. But they may not be unique in the area: A Chester County woman was arrested this fall and charged with giving heroin to her daughter and her daughter's boyfriend.

"It just shows you what a terrible drug heroin is," McLaughlin said.

Davenport's daughter, now 17 and sober, wrote that she "lost everything," including the right to see her brother. As her mother supplied her with heroin, cocaine, and money for marijuana, the girl developed depression and anxiety.

Despite the damage, "being a teenager, I need my mom," she wrote. "And I have to admit that I miss her a lot."

Davenport, 37, let her daughter "wither away," said McLaughlin.

Davenport pleaded guilty in October to four felonies, including endangering the welfare of a child. Standing and sobbing before a judge Thursday as her daughter and other estranged family members sat in the courtroom, she apologized and said her own addiction had clouded her judgment.

"There's no excuse, good or bad, for what I've done," she said.

Likening the mother's actions to infecting her child "with leprosy or cancer," Judge William R. Carpenter said sentencing guidelines were inadequate because no one writing them could have imagined such a crime.

Carpenter said he had seen "a mountain" of terrible crimes during his more than 35 years working in the criminal justice system.

"This one," he said, "is high up on the mountaintop."