Amanda Hein, 26, of Allentown, was charged following the killing on the night of August 18th.
At a news conference on Monday, District Attorney John Morganelli said Hein went to Starter's Pub in Lower Saucon Township with three friends to watch a sporting event.
Investigators say one of the friends told police said he had no idea Hein was pregnant, but saw blood on her pants. That friend said he offered to take Hein to a hospital, but she declined.
At one point, Hein went to the bathroom and gave birth to the baby boy.
Investigators say they interviewed Hein who allegedly admitted to putting the baby inside a plastic bag while still alive, then put bag inside the toilet tank and walked away.
She then went outside to smoke a cigarette, police said.
Authorities say the baby, who was born healthy at 33-36 weeks, suffocated.
A cleaning crew found the body the next day. Police earlier said workers couldn't get the toilet to flush so they lifted up the tank's lid and made the gruesome discovery.
Morganelli said Hein is not yet in custody but is in a local hospital. Officers were able to track her down because her group rented a booth for the game.
"The criminal justice system does have to protect everyone and this is a child who was basically a full-term baby that was born. And whether it was one hour old, or ten minutes old or a year old, it was a person and this person's life was taken," Morganelli said.
Since this is the criminal homicide of a child the case qualifies for the death penalty. Morganelli said he needs to decide if he will pursue that.
Authorities are still looking for the baby's father.