Oklahoma prison officials say a 25-year-old woman convicted of second-degree murder for pushing her husband to his death from the 25th floor of their apartment has died in prison.

Oklahoma Department of Corrections spokeswoman Terri Watkins says Amber Hilberling was pronounced dead at 5:33 p.m. Monday at the Mabel Bassett Correctional Center, where Hilberling had been serving a 25-year prison sentence for the 2011 death of her husband, Joshua Hilberling.

Watkins says the state medical examiner's office will determine Amber Hilberling's cause of death.

Prosecutors alleged that Amber Hilberling shoved her husband through the window after they'd argued over splitting up. Hilberling, who was 19 at the time and seven months pregnant, argued that the death was an accident caused by "unusually thin" windows in the couple's apartment.