UK newspapers have reported on the story of 'twin' girls born 16 years apart following IVF treatment. Jane and Alan Davis began IVF treatment in March 1989. Thirty-three eggs were collected, and fertilised with Mr Davis' sperm, producing a number of viable embryos. Three were implanted and 22 others were kept in frozen storage to potentially be used in the future.
Emma Davis, now 16-years old, was born in December 1989. Her sister, Niamh, who began life as an embryo at the same time as Emma, was born in December 2005. According to UK law, IVF embryos can usually only be kept for five years, with the possibility of an extension. Doctors treating the couple decided that their circumstances were so exceptional that they should be granted a special dispensation to keep their frozen embryos in storage for longer. Although siblings have been born up to 21 years apart after the use of frozen sperm, this means that 16 years is now the record for siblings being born from the same batch of IVF embryos.
'We feel incredibly lucky that we've finally been able to complete our family. It's been a long and traumatic journey, but we're so glad we never gave up', said Mrs Davis who has had ten miscarriages, three ectopic pregnancies and lost a third child - conceived from the same batch of IVF embryos. The ectopic pregnancies, which followed after Mrs Davis conceived naturally after the birth of Emma, damaged Mrs Davis' fallopian tubes so badly that she had no chance of conceiving naturally again. After saving money for more IVF treatment, in 2002, the Davises told Emma they wanted to try for another child using an embryo stored since she was conceived: 'We'd told Emma about the unusual circumstances of her birth and she'd simply accepted it', said Mrs Davis, adding 'she was just thrilled at the prospect of a brother or sister'. However, despite getting pregnant, they lost the baby at six months old. A second attempt ended in a miscarriage and doctors told the couple that embryos could not be kept frozen forever without losing quality.
In April 2005, the couple decided to have one final attempt at IVF. Each time they tried, six embryos were thawed and the best selected for implantation. 'We knew that after this attempt, only three frozen embryos would remain, which might not be enough to keep trying', said Mrs Davis. But this time the pregnancy was uncomplicated. Dr Goswamy, who treated the couple initially at London's Churchill Clinic, and then later at the Harley Street Fertility Centre, said that he believed 16 years is the longest time between siblings born from embryos created at the same time. 'As far as I know, this is a record', he said, adding 'I don't know of any other case, anywhere in the world, where children from the same batch of eggs have been born 16 years apart'.
The Davises are discussing what to do with their three remaining frozen embryos, but are almost certain they will have them destroyed. 'I doubt three embryos is a large enough number to be useful in research', they said. Speaking about her new sister, Emma Davis said that she realises that 'it's very unusual to have a twin sister born 16 years after me'. She added: 'But we're not identical, and I don't really think of her as my twin, more as my baby sister'.
Although theoretically very long-term freezing is possible, the normal period for embryo storage in the UK is limited to five years. However, this story seems to confirm studies carried out on animal embryos, which show that longer-term freezing carries few significant risks. Planer, the company that developed the freezing equipment in which the embryos were stored, said in a press release that Niamh's birth 'is believed to set a new record for viability in the long term'. The previous record was twelve years, when in February 2004 it was reported in that a 39-year old Israeli woman has given birth to twins using frozen embryos created twelve years prior. On that occasion, the embryos had been frozen prior to storage in a controlled rate freezer also made by Planer.