Women receiving advice from pregnancy counselling centres run by faith-based and anti-abortion organisations are subjected to scaremongering, emotive language and inaccurate information about abortion, according to an undercover investigation by a pro-choice charity.

Hundreds of crisis pregnancy centres(CPCs) offer counselling independently of the NHS. They could take over work performed by abortion providers such as Marie Stopes and the British Pregnancy Advisory Service (BPAS), after the government said it was considering handing the counselling role to "independent" organisations.

A survey of 10 centres operated by Christian and anti-abortion organisations found evidence in most of them of poor practice and factually incorrect advice, while the quality of counselling differs widely. Advice ranged from scaremongering – linking abortion with breast cancer, for example – to actions apparently designed to steer women away from abortion, such as showing them baby clothes and talking about "the child".

Researchers pretending to be young women in the early stages of pregnancy conducted the survey for Education for Choice, a pro-choice charity providing education and training on abortion.

Centres visited included those run by Life, recently appointed to a panel advising the government on sexual health. That appointment, as well as renewed pressure from socially conservative MPs to tighten abortion laws and strip abortion providers of their counselling role, has sparked alarm among pro-choice supporters.

At a Life centre in Covent Garden, London, the undercover researcher was given a leaflet entitled Abortions – How they're Done, which said incorrectly that 85% of abortions are carried out using vacuum aspiration. It stated that "the unborn child is sucked down the tube" and that "the woman should wear some protection. She has to dispose of the corpse [in the case of chemically induced abortion]."

The counsellor was said to have focused on mental health issues that she associated with abortion, telling the researcher she was of a good age to have a child, showing her baby clothes and using terms such as "baby" and "grandchild" when referring to the pregnancy.

While a counsellor on Life's helpline was regarded as being "friendly and non-judgmental", she was unwilling to answer questions about physical aspects of abortion, saying she was not qualified to do so. When asked whom to talk to about arranging an abortion, the counsellor stated that the organisation was pro-life and could not recommend any service. She claimed not to know the names of abortion providers.

A counsellor at City Pregnancy Counselling and Psychotherapy (CPCP), London, which came under Life's auspices until the end of May, repeatedly suggested the client should wait two to three weeks before making her decision on abortion.

The counsellor said the embryo was a fully formed human life and that the client would have to grieve for her loss: "Abortion, whatever reason you might go for that, will become bereavement because this is a baby that's going to die, if you go down that route. That's the reality of it."

A counsellor at Choices Haringey in north London, part of a network overseen by Care Confidential, a Christian organisation, did not know the legal time limit for abortion, claimed that there were no statistics on the number of women who have terminations and had little idea about local services.

The counsellor frequently referred to "The Journey" – a training manual – and handed out photocopied pages from its 10-step "road to abortion recovery", including steps entitled "guilt and shame" and "forgiveness".

Other sections of the manual (which were not given to the researcher) state: "Part of the healing journey to post-abortion recovery involves repentance – the only remedy for guilt. If we are to walk this journey with a woman then we need to clearly see which boundaries she has crossed … immorality, coveting, lying, as well as taking innocent life."

A counsellor at Alternatives Pregnancy Choices Newham, a Care Confidential affiliate in east London, was said to have been friendly, well-informed and able to recommend abortion providers, including Marie Stopes and BPAS.

At Skylight Counselling, a Care Confidential affiliate in Coventry, the counsellor was said to have listed physical and psychological effects she linked to the "post-traumatic stress" of abortion. Literature suggesting risks such as "sub-fertility or infertility" and "increased risk of breast cancer" was given out.

Julia Acott, Care Confidential's counselling and support services manager, said the organisation was sorry the service provided at Haringey "fell below the standards expected". The adviser in question would be retrained.

She said Care Confidential became an independent charity on 1 July, adding: "One of the first actions we are implementing is a full review of quality control, training and support across the centres.

"Part of this will include a review of all the published materials, from websites to training manuals, including that for The Journey, where circumstances, thinking and language has moved on in the years since it was published. The training manuals will be updated and rewritten in language that reflects the diversity of people, of different faiths and none, who will use and benefit from it."

Life said: "We are wholeheartedly committed to offering the best service possible to women facing crisis pregnancies by providing them with non-judgmental, person-centred counselling and skilled listening in line with guidelines set out by the BACP [British Association for Counselling and Psychotherapy], of which we are a member.

"The misinformation which allegedly a Life worker gave to a mystery client was apparently contained in a leaflet that was not produced by Life. We therefore can't comment on it but are investigating the overall complaint."

"If asked, we give factual information about abortion and, if the client wants to explore what is involved, we will help her to do so."

CPCP said its policy was that counselling should be non-directive and keep to BACP guidelines.

Lisa Hallgarten, director of Education for Choice, said: "We investigated a range of CPCs because we are asked so regularly by commissioners whether this or that centre is OK to signpost young women to.

"We felt it was in the public interest to learn more about how these services operate. We chose to send in 'mystery shoppers' to use services as this is a tried and tested technique in mainstream sexual health provision - commonly used to test how young people friendly a service is and get a real sense of what it feels like to be a service-user.

"With the localism agenda, new health commissioning arrangements and the Department of Health considering changing abortion counselling regulations, we expect commissioners to come under increasing pressure to use CPCs."

"Only two of the 10 centres we looked at provided good quality information or support.

"We strongly urge the Department of Health to think carefully about removing women from the professional decision-making support currently offered by abortion providers while the current alternative is a network of unregulated individuals, many of whom are in breach of good practice."

• This article was amended on 4 and 5 August 2011. The introduction and headline were updated to correspond with the newspaper. In addition, a reference to a woman disposing of a "corpse" has been updated to clarify the method of termination involved.