Mubashra Uddin, 20, from Chicago, USA, plead guilty to involuntary manslaughter on Thursday.
She originally was charged with first-degree murder for the November 2015 death.
Uddin became pregnant by her boyfriend, but didn't tell her parents, who are from Pakistan, because she feared they wouldn't approve, prosecutors said.
After giving birth to the infant, Baby Jane Uddin, she threw her out the eighth-floor window when she heard her mother approaching her bedroom.
A man found the baby, barely breathing, outside the high-rise apartment block, but she was pronounced dead after arriving at hospital.
According to The Chicago Tribune, Uddin's family was 'standing by her' at the time she was charged.
At her sentencing, Uddin was given credit for serving 603 days in jail. She was sentenced to at least 48 months' probation.
'This has been a tragic event in the life of a naive 19-year-old girl,' one of Uddin's lawyers, Adam Shepherd, told the newspaper in a statement.
'Although she will be forever haunted by what occurred, the end of this case will enable her to salvage the remainder of a productive life.'