An official report into the IVF blunder that led to mixed-race twins being born to a white couple has blamed "a mixture of inadvertent human error and systems failure" for the incident.
The investigation ordered by the chief medical officer, Sir Liam Donaldson, looked at four "adverse events" at the medical reproduction units at the Leeds teaching hospitals trust, West Yorkshire.
Two cases - including that of the twins - involved the incorrect identification of sperm, one involved the loss of embryos following failure to check liquid nitrogen levels in a cryogenic freezer and in one case, embryos were disposed of "following an administrative failure".
The report, by Professor Brian Toft, visiting professor of risk management at Coventry University, concludes that it was impossible to say at which point in the IVF process the sperm of two male donors in the twins case were confused. But it says: "A number of weaknesses were found in the practices and protocols used in the embryology laboratory."
It notes that patients were placing sperm samples in an unsealed box - a practice which was "not desirable". The report makes a series of recommendations on securing and labelling sperm samples.
It also suggests that staff shortages at the Leeds centres could have contributed to the problems there. "There is evidence to suggest that the embryology staff felt that the volume of work was too high for the number of embryologists available," Prof Toft's report says.
The report adds that there are no professional or regulatory guidelines about the number of staff required for a given number of patients.
Professor Toft also lambasts the IVF watchdog, the Human Fertility and Embryology Authority (HFEA), which inspects and licences reproductive treatment centres, saying financial cuts had led to a less robust inspection regime.
The HFEA's workload had increased rapidly since it was set up in 1990, while the budget had, until recently, remained static. "The need for continued financial saving has affected the Authority's approach to its statutory duties, including a change in 1999 to what we consider a less robust approach to inspections," the report says.
The report also criticises the culture of the HFEA which had developed in a way that appeared to make it difficult for the committees that license reproductive centres to censure them where necessary. There was a "culture of secrecy" at the HFEA, it adds.
The HFEA also showed "potential vulnerabilities" in the arrangements for selecting and training authority members and had "weaknesses" in its risk-management, administrative and document archiving systems.
Prof Toft found that facilities at the two sites of Leeds' reproductive medicine centres were "not optimal" but this was expected to be solved by a merger. The HFMA did not judge the facilities to be unsafe sand so did not impose renewal conditions on the centres' licences requiring facilities to be improved "even though the person in charge of one of the centres had asked them to do so," the report says.
Sir Liam Donaldson responded: "The mistakes detailed in this investigation were enormously distressing to the patients involved and their families. Lessons will be learned from what happened so that we can reduce the chance that anything like this will happen again.
"Patients undergoing assisted conception treatment should feel confident in the services provided. Professor Toft's report contains some practical and achievable recommendations. I understand that improvements to address these recommendations have already taken place at both the HFEA and the Leeds trust."
Prof Toft said: "The starting point for this review was that patient safety is paramount. Patients need to be confident in the assisted conception treatments they are receiving. During this review we identified a number of potential vulnerabilities and weaknesses in the regulatory procedures and clinical systems that were in place when the incidents occurred. The review panel has made a number of recommendations to address these.
He added: "However, it is important to bear in mind that these events occurred before July 2002. Both in the course of the review and since, the HFEA and the Leeds trust have been addressing the concerns identified and I am confident that they are putting in place the necessary arrangements to make significant progress."
