Claudia Martins, 33, gave birth alone in the bath at her sister's flat in Knowle, Bristol, having allegedly kept the pregnancy a secret.
At Bristol Crown Court, Ms Martins denied a single charge of murder on 12 September 2014.
Police found the baby's body in a suitcase after Ms Martins had initially denied she had been pregnant.
Paramedics were initially called after family and friends found Ms Martins in the bath with "a lot of blood".
She was taken to the Bristol Royal Infirmary where she repeatedly told medical staff she had not given birth or been pregnant.
Two days later, police were called to the flat and found the body of a newborn baby inside a small black suitcase.
Ms Martins, a Portuguese national who is described as having an extremely low IQ, was arrested and admitted that she had given birth, but said the baby was stillborn.
A post-mortem examination found a wad of toilet paper inside the girl's mouth, which experts claim was "deliberately inserted".
Prosecuting, Adam Vaitilingam QC, said two police officers were called to the flat Ms Martins shared with her sister, Vilma Marshall, on 15 September last year.
They were shown to the bathroom of the flat, where they saw and opened a suitcase.
"Inside, wrapped in towels and in a black plastic bag, they found the body of a newborn baby girl," he said.
"The baby had been born three days earlier to the defendant, Claudia Martins.
"It is the prosecution's case that she killed the baby as soon as it was born and that she hid the body in the suitcase.
"It is the defence case that she never knew she was pregnant and when she gave birth it was stillborn and that she hid it in the suitcase out of a mixture of shock and panic."
The jury heard Ms Martins is originally from Mozambique but moved to Portugal before settling in Bristol in 2011.
The case continues.
A mother murdered her newborn girl by filling her mouth with toilet paper before hiding the body, a court heard.