A teenage father accused of murdering his seven-week-old baby attacked his partner while she was pregnant, a court has heard.
The 17-year-old is accused of killing the boy by biting his nose and "violently swinging or shaking" him at a flat in Southampton in February.
The court heard he pushed the baby's mother to the ground, injuring her face, whilst she was pregnant.
The father, who cannot be named for legal reasons, denies murder.
The baby's 19-year-old mother denies a charge of cruelty to her son by failing to protect him from the attack and by failing to summon help quickly.
At the start of the trial on Tuesday, Winchester Crown Court heard the baby suffered fatal injuries, including a skull fracture, broken leg and rib fractures.
Jurors heard residents of a neighbouring block of flats heard "blood-curdling screams" at the time of the alleged attack, which happened in the early hours.
'Pushed with force'
On Wednesday the court heard that in October 2017 the child's mother, who was 18 and pregnant at the time, suffered injuries to her face and hands when she was pushed to the ground by the father after an argument.
Her sister told jurors: "She said he pushed her with some force and she fell to the floor."
The jury was shown a photograph taken by the sister of the mother's grazed face after the alleged incident.
The sister said: "She told me he phoned her, he called her a slut, called her a slag and said the child she was carrying wasn't his."
'Born to be a mum'
The sister said that she and her partner visited the defendants on the evening before the baby died and he was "asleep and calm".
She added that her sister had been happy to have a baby, adding: "It was like she was born to be a mum."
Jurors heard from a neighbour who said that on the same evening the defendants attended a gathering at another flat in the block where they lived.
She told the court that said the mother drank vodka and the father drank lager.
She said that during the party she changed the baby's nappy but did not see any injuries on the child.
The trial continues.