Stephen Cahoon, 37, of Harvey Street, Derry, admits killing his ex-girlfriend Jean Quigley but has denied a charge of murder.
The jury was told that the 30-year-old woman's body was found at her home in the Shantallow area of Derry on 26 July last year. She had been badly beaten and strangled.
Stephen Cahoon told the court he grabbed Ms Quigley by the throat after she began screaming at him to get out of her house. He said she was saying she would have an abortion and he snapped.
He said he realised she was dead when she did not move for about five minutes.
Mr Cahoon said the reason he did not call the police was because he panicked and thought she might still be alive.
He said he left the house and went to a park where he sat crying on a bench for a couple of hours. He then went home and slept before taking a bus to Galway and later Donegal town where he was arrested 11 days later.
Ms Quigley had been in a relationship with Stephen Cahoon which had ended two weeks previously. She was ten weeks pregnant at the time.
The accused said he and Jean Quigley had loved each other in the short time they were together.
He said they were delighted about her pregnancy but he was later told by a friend that she had only got pregnant to get back at her ex-partner of 12 years.
