Moves to reveal more information on the number of abortions carried out because of unwelcome medical conditions in the unborn child have started today.

The Information Tribunal has begun considering a request by anti-abortion group ProLife Alliance for the release of figures concerning terminations carried out for reasons such as the unborn baby having a club foot, cleft palate or webbed toes or fingers.

The appeal panel will listen to Department of Health officials who have argued that the figures must remain confidential because where there are fewer than 10 cases in such a category, there is a risk the women or doctors involved could be identified.

Such data was published up until 2002. The ProLife Alliance has challenged the change in practice and requested release of the figures under the Freedom of Information Act.

Last year the Information Commissioner ordered ministers to publish the data but the Department of Health refused and appealed against the commissioner's decision.

Ministers originally called for the hearing to be held in private so the data could be discussed. An agreement has since been reached with the Information Commissioner's Office for part of the hearing to be held in private.

Abortions can be carried out up until birth under category E, which relates to disability, as long as two doctors agree the procedure should be performed. There is no list exempting conditions such as cleft palate or club foot.

A spokeswoman for the ProLife Alliance said: "We believe there should be absolute transparency and openness about these statistics. Abortion is not a right; it can be performed if you fulfil certain conditions under law. Otherwise it remains a criminal act.

"We have been very clear that we have asked for information about all abortions, not just those after 24 weeks. This case is about transparency."

Among witnesses for the alliance during the four-day hearing are Ann Widdecombe MP and Professor Stuart Campbell, a pioneer in ultrasound techniques in obstetrics.

A spokesman for the Department of Health said: "Data on abortions is considered highly sensitive personal data. The Office for National Statistics guidance does not recommend releasing any data with a count of less than 10. Releasing such data could increase the risk of identifying individuals.

"The guidance provides clear boundaries to make as much information about abortions available as possible, while protecting the individuals concerned — both patients and doctors."