Ms B, whose identity is protected by a High Court injunction, is a middle- class professional woman who lives in London with her husband, a company director, and their children, according to reports in the Daily Express. She underwent the termination of one healthy twin in March this year, and is now awaiting the birth of the surviving baby.
Anti-abortion groups said that the truth about the woman's circumstances made the case "even more shocking", while Elizabeth Peacock, a Tory MP, called for reform of the abortion law to prevent the use of terminations as "afterthought contraception" by well-off parents who want to create designer families.
Queen Charlotte's Hospital, where the abortion took place, refused to confirm or deny the Daily Express's claims yesterday, although it initiated the injunction after journalists approached Ms B at her home.
A spokesman said that some of the details about the woman which Professor Phillip Bennett, an obstetrician and gynaecologist at the hospital, had originally supplied to the Sunday Express - which first published the story - were deliberately falsified in order to avoid breaching patient confidentiality.
Anti-abortion campaigners raised pounds 80,000 last week after hearing that the mother was planning the selective termination for lack of money to bring up the babies.
The campaign came to an end when Queen Charlotte's revealed later that week that the abortion had taken place several weeks earlier. The hospital claimed that the Sunday Express journalist who wrote the story was aware of this fact but chose to ignore it because it diminished the story. It also said that it was unable to tell the media this until the woman herself had given approval.
Professor Jack Scarisbrick, chairman of Life, the anti-abortion charity, said that the new information showed that the operation was "carried out for the flimsiest of medical reasons ... it makes it even more shocking. This case shows how cheap human life has become and how respect for it has dwindled amongst doctors.
''All those lies by the doctors and the hospital were unnecessary. They should have come clean with the facts, instead they realised what a nasty story it was and had to tart it up."
Ann Winterton, Conservative MP for Congleton and chairman of the Commons all-party "pro-life" group, added: "I think the selective culling of this perfectly healthy twin touched the hearts of many people in this country.
''It appears now that apparently the public has been misled yet again and I think they will be even more concerned to learn of the circumstances of this particular woman. And the reasons for the selective killing of one of these infant twins were not in fact as stated originally."
Speaking on BBC Radio 4's Today programme, Jonathan Street, a spokesman for the hospital, said the public had no right to know the circumstances of a patient in any case.
"Just one headline in a newspaper is not going to change our view that we are protecting this patient's confidentiality... The only people who have the right in law to know about her are her medical team," he said.