Alder Hey children's hospital, being investigated for removing the organs of 850 dead children without their parents' consent, has confirmed its chief executive has taken extended leave.

Hilary Rowland left her post on Friday for what a hospital spokeswoman called "a well-earned break". The hospital declined to comment on whether Ms Rowland would return to work at Alder Hey. She has been replaced by Tony Bell, a director of Liverpool Health Authority.

The spokeswoman described Ms Rowland's move as "an abeyance".

She added: "Everyone recognises this has been a particularly difficult and demanding time for Hilary, who has worked tirelessly to deal with this very sensitive and complex matter and who, despite all the issues, has ensured the day-to-day services have not suffered. Therefore you will not be surprised to know she is taking a well-earned rest."

Mrs Rowland's decision is another blow to Alder Hey. On Friday, the Health Minister, Lord Hunt of Kings Heath, said the management of Alder Hey's pathology service would be tightened.

A report into the case of 10-day-old Stephen White found the baby's funeral could not go ahead because his heart, brain and one lung had been lost.

The scandal caused last week's sacking of Frank Taylor, the chairman of the Royal Liverpool Children's Trust, which includes Alder Hey. The controversy surrounding the retention of organs first came to light last September during a public inquiry into baby deaths at Bristol Royal Infirmary.

That led to disclosures that thousands of organs had been removed from dead children without parental consent.

New rules governing the retention of organs from dead patients have been drawn up by the Royal College of Pathologists. The rules were published last week in advance of inquiries into the practice at both Alder Hey Children's Hospital and the Bristol Royal Infirmary.

The college says relatives must always be told what has been taken and why, and greater efforts made to ensure they understand medical terms.

Doctors are worried that medical advances may be impeded if a public backlash halts the removal of organs for research.