The woman was several months pregnant with Keian Higham's twins when he kicked her in Abbots Road in Shrewsbury after she met him to give him back some of his belongings, two weeks after she had told him she did not want to be with him anymore.
She rushed to hospital because she feared for her unborn children after the attack by their father, Shrewsbury Crown Court heard on Wednesday.
Higham, who was 17 when the relationship began and is now 18, had subjected the woman to six serious assaults and strangled her twice between June and November last year.
Police spoke to the victim on November 15 last year after she had reported an assault by Higham, and she went on to share details of the other attacks over the course of their six-month relationship.
Appearing by video link at the court, prosecutor Mr Nicholas Tatlow said that the two were laying on Higham's bed on June 17 last year when they began arguing and he slapped her thigh hard enough to leave handmarks.
On July 20, Higham "lost his self-control because he didn't have any cannabis", said Mr Tatlow.
"He began to throw things at her. She left the house... he followed and he put her to the ground by sweeping her legs. He kicked her about the body."
Higham, of Clive Green in Shrewsbury, was arrested after that attack but denied any wrongdoing and was released on bail, the court heard.
On August 25 Higham strangled the woman by grabbing her around the throat and squeezing tight, all in the presence of her very young son.
To avoid upsetting her son, the victim tried to pretend she was "being silly" with the defendant, Mr Tatlow told the court.
On October 31, the couple had argued outside a hotel in Shifnal and the victim told Higham she did not want to be with him. He followed her to her car and after a scuffle she was shocked when she felt a pain in her leg and saw that he had bitten her on the knee, the court heard.
Another attack followed on November 6 after the heavily pregnant victim did not give Higham a lift in her car because she was feeling ill.
He choked her again, placing both hands around her throat and squeezing.
There was also an incident of criminal damage in which Higham threw dinner plates at the victim's car.
The final assault took place on November 15, in which Higham "kicked her in the stomach in a 'karate-style' kick" when she went to give him back some of his belongings, Mr Tatlow told the court.
"She was winded and went to the ground. She went to hospital because she was concerned for the welfare of her unborn twins."
The court heard that the babies have since been born.
Higham was arrested, and was "belligerent and aggressive" to police who interviewed him, said Mr Tatlow.
He denied ever being violent towards the victim, but a month later on December 17 he pleaded guilty to six charges of assault occasioning actual bodily harm, two of strangulation and one of criminal damage.
A statement made by the victim and read out to the court said that Higham had prevented the victim from seeing her friends and family and "tried to make [her] completely reliant on him".
For Higham, Mr Rob Edwards said: "He is frankly disgusted with what has been described and what he has done.
"It was his first real relationship. He was very young when he got into the relationship, frankly he was not mature enough to enter into a relationship of such intensity and he was not mature enough to become a father.
"That is no excuse."
Judge Peter Barrie told Higham: "You have shown through the way that you behaved with [the victim] that you were unable to control your temper. You were self-centred and manipulative in the way that you behaved."
He handed down nine sentences: for the first assault on June 17, six months; for the second assault on July 20, eight months; for the assault on August 23, 20 months; for the strangulation on that day, 20 months; for the assault on October 31, eight months; for the criminal damage, one month; for the strangulation on November 6, 20 months; for the assault on November 6, eight months; and for kicking her stomach on November 15; 20 months.
They will all run concurrently, meaning Higham was sentenced to 20 months. He will serve 10 months in a young offenders' institute and the rest on licence.
Judge Barrie also made a restraining order barring the defendant from contacting the victim.
West Mercia Police's Detective Constable Geoff Anslow of Shrewsbury CID said after the case: “This was a particularly nasty case of domestic violence which not only endangered the victim but also her unborn children.
“The victim has shown a lot of courage throughout the case. No-one should have to experience domestic abuse, and we will leave no stone unturned in bringing those responsible to justice.”