Unbelievable Story : Baby Born Pregnant with Her Own Twins .

A baby born in Hong kong was pregnant with her own sibblings at the time of her birth according to a new report of the infants case.

The baby's condition known as Fetus-in Fetu is incredibly rare, occuring in only about 1 in every 500,000 births. It's not clear exactly why it happens.

"Wierd things happen early, early in the pregnancy that we just do not understand," said doctor Draion Burch; an obstetrician and gynecologist in pittsburgh, who goes by Dr. Drai. "This is one of those medical mysteries."

The world health organistaion considers a tiny fetus found within an infant to be a kind of teratoma, or Tumor, rather than a normally developing fetus. But the doctor who treated the baby girl wrote that rather than a teratoma, the tiny fetuses may instead be the remains of sibbling twins that were absorbed during pregnancy.

The new born baby was referred to Dr. Yu Kai-Man, an obstetrician and gynecologist at Queens Elisabeth Hospital in Hong Kong, because the baby was suspected to have a tumor, according to the case report. The mother's prenatal ultrasound had revealed an unusual mass within the infant, but it was unclear to the doctors what the mass was.

During surgery, which was done when the girl was about three weeks old, the surgeons discovered two fetuses between her liver and her kidney.

One fetus weighed 0.3 ounces(9.3 grams) and the other 0.5 ounces(14.2 grams)- corresponding to about 8and 10 weeks gestation; the case report said.

Each of the babies had an umblical cord that linked to a placenta-like mass in the girls belly.

The baby was obviously too young to have conceived the fetuses herself, instead, it is likely that the girl was once one of the triplets, the researchers said.

Then, for some mysterious reasons, the two small fetuses were absorbed into the body of the remaining child. The fetuses would likely had still been alive and growing when they were absolved into the surviving baby's body. Once there, however their development couldn't proceed normally, Burch said.

"they need placenta flow and all that other stuff to really grow," Burch told live science.

Fetus-in-fetu, infact be similar to a surprisingly common phenomenon: varnishing twin syndrome, Burch said. In many twin prenancies, one of the twins is completely absorbed and "varnishes"into the body of the other.