Dalene Petersen, 32, made her first appearance at the Mitchells Plain Magistrate's Court on Tuesday after being arrested on Saturday night.
The incident happened at the mother’s Beacon Valley home.
According to a source close to the investigation, the 32-year-old mother told police that she already had four children and had hidden her pregnancy from her family.
It is believed the baby was from a married man.
She gave birth in her house and then hid the newborn in a cupboard. When neighbours came knocking, they questioned her about screaming they had heard and noticed blood on the floor.
When they left, she allegedly strangled the baby boy to death and hid him under a mattress, the source says.
Outside court, people could be heard talking about how shocked they are over the case.
One woman was heard saying: “Ons kannie judge nie. Ons weet nie wat gebeur het nie. Julle is nie perfect nie.”
Residents filled the courtroom as Petersen appeared before Magistrate Alwira Bezuidenhout.
Wearing a pink hooded jacket and a blue pants, a seemingly irritated Petersen turned to look at the public gallery several times before being instructed to face the magistrate.
Bezuidenhout informed Petersen that she had the options of hiring her own lawyer, applying for legal aid or defending herself.
“Ek gaan myself verdedig,” Petersen said.
The magistrate pointed out to her that it was a serious charge, and Petersen then agreed to take a Legal Aid lawyer.
Prosecutor Farieda Jacobs called for the matter to be postponed until 26 September for further investigations.
Bail will also be heard that day and Petersen will remain in custody until then.
The accused’s four children have been sent to stay with relatives in Mitchells Plain.
Joanie Fredericks, chairperson of the Mitchells Plain Crisis Forum (MPCF), says they are distraught by the senseless killing of the newborn baby.
“We welcome the arrest. We support the voiceless. What she did to the child is cruel and calculated murder,” an angry Fredericks said.
“The baby was already born and alive and she had the choice of giving it up for adoption. Instead she not only killed the baby, but tried to cover up the murder.”
Mitchells Plain Crisis Forum spokesperson Faizel Brown called on residents who have information to come forward.