A 37-year-old mum-of-two drank half a litre of vodka before putting her baby in her car and driving off on the afternoon school run.
The woman, who cannot be named for legal reasons, was nearly four times over the drink-driving limit.
She eventually crashed her vehicle into a wall, and her friend, who was in the car with her, had to rescue the baby.
The friend then phoned the woman's mother who contacted the school ,where teachers refused to hand the child over to the intoxicated mum and called the police.
When officers arrived, the woman became aggressive and attacked one of them.
The incident occurred on July 8 as the woman tried to make her way to her son's Wirral school three miles from her home.
Appearing in court yesterday, she pleaded guilty to drink-driving, assaulting a constable and being drunk while in charge of a child under the age of seven.
Lionel Cope, prosecuting, told the hearing: "Once in the vehicle, the defendant drove the vehicle into a wall. It was at this point the passenger realised she was drunk but she refused to stop the vehicle. The passenger got out of the vehicle and tried to get the baby out but the defendant drove off.
"While sat in the patrol car, the defendant started to become aggressive and loud. She suddenly attempted to climb into the front of the patrol car and into the driver's seat. The constable was concerned she could intentionally or otherwise apply the vehicle's handbrake from this position and attempted to control her. The constable was then kicked twice to the left leg and while attempting to apply handcuffs was bitten to the left thumb."
The woman's lawyer Matt Harvey said his client was remorseful and seeking help for her drink problems.
"While at the school, she accepts the teachers had due cause to stop the child being allowed to be in her car," he said.
The Liverpool Echo reports that magistrates gave the woman a four-month suspended sentence and banned her from driving for 36 months.