By Lucy Laing
London - Little Alice Baxter is three years older than her baby brother and sisters - but incredibly they are quadruplets.
The four children were all conceived at the same time - yet Alice was born in 2007, while her siblings arrived in January.
Their mother Helen Baxter had her remaining embryos frozen after getting pregnant with Alice.
But when doctors defrosted and implanted them last year, no one expected all three to take hold.
In fact it is the first time experts at the Care Fertility clinic in Nottingham have seen such a set of births.
"It is most unusual to see triplets born from frozen embryos after a successful previous pregnancy from the same batch," a spokesperson said. "We have never seen it before and we are thrilled for the parents.
"They now have four children who were all conceived at the same time."
Mrs Baxter, 41, and her engineer husband Shane, 37, had been trying for 18 months for a family when they underwent fertility treatment.
Tests had shown that Mrs Baxter, a personnel manager of Grantham, Lincolnshire, had scar tissue on her fallopian tubes so was unlikely to conceive naturally.
In May 2006 the couple went to the Care Fertility clinic where Mrs Baxter had two fertilised eggs put back into her womb and four frozen.
Two weeks later she discovered she was pregnant.
"We were thrilled," she said. "One embryo had survived. I couldn't wait to be a mum."
Mrs Baxter's pregnancy went smoothly and Alice was born in February 2007 at City Hospital in Nottingham, weighing a healthy 7lb (about 3kg).
Soon after, the couple began trying for another baby, this time naturally, but after two miscarriages they returned to the IVF clinic and the frozen eggs.
Mrs Baxter had three implanted, hoping one would develop. But she "nearly fell off the scanning table in complete shock" when her eight-week scan revealed she was expecting triplets.
The babies, who are non-identical, were delivered by caesarean six weeks early at Queen's Medical Centre in Nottingham.
Noah and Niamh weighed 4lb and Maisy just 2lb.
All are now at home, where they are doted on by big sister Alice.
"She has waited a long time for her brother and sisters," said Mrs Baxter. - Daily Mail