ALLENTOWN, Pa. (CBS) — A 21-year-old woman was sentenced in the murder of her young son on Friday.

Authorities say Johnesha Perry, of Allentown, pushed her child off of the Hamilton Street Bridge before jumping off of the bridge herself on May 3, 2015.

The 20-month-old child died six days later.

Chief Deputy District Attorney Matthew Falk stated that Perry ”has real mental health issues, and while they certainly do not absolve her of the responsibility of this monstrous act, we believe that they, along with her low IQ, require us, in fairness, to offer this plea.”

A Mitigation Specialist gave background of Johnesha’s childhood, which allegedly included sexual abuse by her brother, and also by men her mother allegedly allowed to molest her.

Further, it was alleged that her mother drank heavily while pregnant with Perry.

Johnesha Perry pleaded guilty to murder of the third degree and was sentenced to 20 to 40 years.