Martin Shuttleworth, 29, of Broadgate, Preston, was jailed for 18 months after admitting causing actual bodily harm.
Preston Crown Court heard he has 14 convictions for 17 offences including assaults against women.
Judge Timothy Hannam told him: “You are a large man, 6ft 3in and well built, she on her evidence, is 5ft 7in and not strong.
“She was feeding him when the incident occurred. Nothing begins to justify what you did next as I’m sure you now see all too clearly.
“She was extremely frightened, unsurprisingly. Fearing death she ran to her friend’s address.”
Shuttleworth sat in the dock with his arms folded as the court heard he and his victim had been in an on off relationship for three years and had a seven month old.
It was “peppered with incidents of violence” but on November 28 the couple spent the evening together, sharing a meal and drinks.
Prosecuting, Emma Keogh said the mum was annoyed Shuttleworth, who was supposed to be staying over to help with the baby, feel asleep on the settee was not in bed and was annoyed. The couple started arguing and she made a comment referring to a previous partner treating her nicely.
Shuttleworth punched her with the baby in her arms. She put the baby down and fled onto the landing but he caught her and lifted her off her feet with his hands around his neck, making threats to kill her.
The terrified mum ran in her nightwear to a neighbour’s but was followed by Shuttleworth who threatened to stab her.
Defending, William Donnelly acknowledged it was a “serious and unpleasant offence”.