Gynaecologist and obstetrician Reginald Dixon said he knew from Barbara Whiten's medical notes that she gave her religion as Church of England.
But he told a jury at Nottingham Crown Court, where he denies unlawfully procuring a miscarriage, there was a "seriously significant risk" that allowing Mrs Whiten's pregnancy to continue might lead her to commit suicide in the future.
"An unplanned and unwanted pregnancy is a greater risk than the termination of an unwanted one," Mr Dixon said.
He admitted he did not mention this concern in his notes on the operation. "The notes were written at the end of a busy morning and were written in a hurry", he said.
Mr Dixon was supposed to perform a hysterectomy on Mrs Whiten, 38, at Kings Mill hospital, Sutton-in-Ashfield, Nottinghamshire, in March 1993. He discovered during the operation that she was pregnant but continued, which meant aborting the 11-week-old foetus.
Mrs Whiten did not discover she had been pregnant until after the operation. She had desperately wanted a family but had been told her illness made her infertile.
Mr Dixon, 59, said he believed his patient did not have endometriosis, a painful womb condition, as she had been told. He thought she had some other unspecified internal pain.
"If I had gone into the details and spent a great deal of time I am sure she would have said to me 'I don't care what I have got, I want relief from the pain'," he said.Reuse content