The Sun
DOCTORS were shocked to find a newborn baby girl had a twin growing inside her.
The extremely rare phenomenon is seen only about once in every 500,000 births.
The girl was born earlier this month at Assuta Medical Center in Ashdod, Israel.
The hospital said Tuesday that medics had been aware in the later stages of pregnancy that the unborn girl’s stomach was enlarged.
After she was born, she was checked over with immediate ultrasounds and X-rays, The Times of Israel reports.
Inside the infant was an embryo – which is the baby before around 10 weeks after conception, when it becomes a foetus.
During the first ten weeks, the embryo develops a brain, heart, basic facial features, arms and leg buds.
But it’s tiny – around the size of a rubber on the end of a pencil.
Omer Globus, director of neonatology at Assuta, said the embryo was not fully formed but had “bones and a heart”.
“But it did not look like an embryo as you imagine it,” he said.
“We were surprised to discover that it was an embryo.”
A team of the medical center’s top experts operated to remove the embryo and found two similar sacs in the girl’s stomach.
Mr Globus said: “We think that there was more than one there, and we are still checking that.”
It suggests potentially there were once triplets growing in the mother’s womb.
The medical condition was named as “foetus in fetu”, according to reports.
It occurs in about 1 in 500,000 live births and less than 200 cases have been reported in medical literature, a 2019 British Medical Journal paper claims.
The abnormality is mainly seen in newborns.
However, there have been seven cases reported where the condition is not found until the person is over 15 years old, with the BMJ paper describing an adult woman with the condition.
Mr Globus said: “It happens as part of the fetal development process when there are cavities that close during development and one of the embryos enters such a space.
“The foetus inside partially develops but does not live and remains there.”
Foetus in fetu often starts as, or is also called, parasitic twin.
This is when one twin stops developing but is physically attached to its other twin.
Although the underdeveloped twin has died, it ends up sharing a blood supply with its twin and embeds onto or inside its body.
Foetus in fetu is a parasitic twin that’s completely enclosed inside the body of the healthy twin, according to Healthline.
It can go undiscovered at birth and even when found, thought to be a tumour.
Other cases of one twin or triplet disappearing can sometimes be known as vanishing twin.
This is when both twins were confirmed with ultrasounds, but in later tests only one remains. The “vanishing” twin is absorbed by the body of its other twin, or compressed by it.
Both the Israeli girl and her mother are doing well and have been sent home.
