A baby girl in China was born carrying two fetuses in her abdomen the Hong Kong Medical Journal has reported.

In prenatal scans a large mass was seen in the baby's abdomen which doctors believed could have been a tumour. When the baby was born she was admitted to a neonatal unit and at 14 days new scans revealed the mass was in fact made up of two separate structures.

When these were removed they were found to be two small fetuses, complete with spines, well-developed rib cages and primitive brain tissue.

The fetuses removed form the baby girl's abdomen

The baby girl made good recovery from the operation and has been discharged from hospital.

Less than 200 cases of twin fetus-in-fetu, as this phenomena is known, have been reported worldwide and is estimated to occur in just 1 in 500,000 births.

It is not yet known how this occurs, some believe it could be the case that a baby in the womb absorbs a twin (or in this case two triplets). Although the World Health Organisation defines it as a type of cancer.