The woman from Michigan, identified as Aimee L Sword, had given her son up for adoption when he was an infant. Sword traced her son, who is now 16, through Facebook.
"When she saw this boy, something just touched off in her - and it wasn't a mother-son relationship, it was a boyfriend girlfriend relationship," her attorney Mitchell Ribitwer said after informing the court Sword had been sexually and physically abused as a child.
"Aimee's searching for a reason why this happened. She can't understand it. She's going to get some counselling," the lawyer added.
After Sword pleaded guilty, the court sentenced her to a prison term of nine to 30 years.
The boy, who was adopted by a family in Grand Rapids, reportedly knew that Sword was his biological mother.
Quoting investigators, the Detroit Free Press reported that the woman had sex with the teen in a Grand Rapids hotel and also at homes in Waterford in 2008.
Sword was not only married but also had five children of her own when she committed the crime.
The boy stayed with Sword for a while before he returned to his adoptive family. The incidents came to light when the boy spoke to a counsellor.