Lorie Bendorovich, 39, will be sentencing in about 60 days and could face more than a year in prison.
Family members discovered the baby's body back on July 15th after noticing a 'smell of decomposition,' investigators said.
An autopsy later determined the baby had been stillborn.
Investigators earlier said Bendorovich claimed not to know she was pregnant until she gave birth, but police dispute that claim.
However, police said they uncovered emails that she allegedly exchanged with the baby's father. They say she told him she had an abortion.