An IVF couple whose last embryo was implanted in the wrong woman by mistake today said they hoped lessons could be learned from their traumatic experience.
Their plea came as it emerged that the fertility clinic where the blunder was made had two near miss mix-ups the previous year.
The couple, from Bridgend, south Wales, identified only as Deborah and Paul, were hoping to try for a second baby with their last surviving embryo in December 2007 when they were told of the error.
The woman wrongly implanted at the IVF Wales clinic, in Cardiff, chose to have a termination after finding out what had happened.
Cardiff and Vale NHS Trust has apologised after admitting liability for gross failures in care and has paid the couple an undisclosed sum.
The couple's solicitor, Guy Forster, said: "Our clients' motivation for pursuing a legal case was to obtain answers as to how this could have occurred but, most importantly, to ensure lessons are learned."
Deborah and Paul were originally referred to IVF Wales after an ectopic pregnancy in 1996 caused damage to Deborah's fallopian tubes.
In 2000 the couple began fertility treatment and three years later Deborah gave birth to a son. But their plans to extend their family were cut short.
Deborah, now 40, said: "I will never forget the moment the hospital broke the devastating news to us. I just could not believe what I was hearing.
"Initially the hospital staff told me there had been an accident in the lab and that the embryo had been damaged, I thought that someone had perhaps dropped the embryo dish.
"I remember thinking, 'That's our last hope gone — we will never have another child.' I left the hospital feeling totally shell-shocked.
"When we went back to the hospital two days later and we were told the truth about my embryo being given to someone else; I was so angry.
"I had been given a handbook before every course of IVF explaining all the elaborate precautions the clinic undertook to ensure this sort of mix-up was impossible — and yet despite everything, it had still happened. "
Mr Forster described the mistake as "an accident waiting to happen".
He said that against all guidance, more than one patient's embryos were being temporarily stored in the incubator.
A trainee embryologist failed to carry out 'fail-safe' witnessing procedures to ensure the embryo being taken from the incubator and implanted, belonged to the correct patient.
He said: "A report by HFEA (Human Fertilisation and Embryology Authority) investigators shows that the error occurred primarily due to failures by laboratory and theatre staff to carry out basic procedures.
"However, it is clear that there were a number of system failings, in that the clinic had failed to implement the procedures set out in the HFEA's Code of Conduct, workloads were above safe levels and there were staff shortages.
"IVF Wales reported two 'near miss' incidents to the HFEA in 2006 and an HFEA inspection in February 2007 had warned the clinic to tighten its witnessing procedures, yet it would seem nothing was done."
Ian Lane, the health trust's medical director, said: "We apologise unreservedly for this mistake.
"This was a rare but extremely upsetting incident for everyone involved and we take full responsibility for the distress caused to both couples and their families."
He said measures were being put in place to prevent such a mistake from happening again.
"As a result of both of these investigations, we have made a number of improvements to our systems and checks, in line with the recommendations made in the reports," he said.
"We have strengthened our protocols and reduced our workload to relieve pressure on staffing levels.
"Working conditions at the unit have since improved and we are continuously monitoring the safeguards and procedures we have put in place."
Mr Forster said he was concerned the HFEA had missed opportunities to take action in relation to IVF Wales before this incident occurred.
An HFEA spokeswoman said that because the IVF process involves microscopic materials it was impossible to eliminate all human error and clinics were encouraged to report any incidents.
She said IVF Wales an inspection was immediately carried out after the clinic reported the incident and they were found to be making progress following up recommendations.
A scheduled inspection took place in March 2008 and the clinic was found to have put in place everything they should have done, the spokeswoman said, so its licence continued with no conditions.
The news follows reports that a white couple in Northern Ireland is to sue Belfast Health and Social Care Trust after an IVF mix-up that saw the woman give birth to a mixed race baby. That case is expected to start in September.
PA