A baby girl with two heads was born at Dr. Jose Fabella Memorial Hospital (FMH), a government hospital in Manila, the Philippines on Tuesday night.
"Baby Girl Arciaga," now under observation at the Philippine Heart Center, was born with two hearts contained in one sac. The heads have separate brains and spines, but share most other vital organs, including lungs and kidneys.
"This is a very rare case. It's new even to us," Dr. Ruben Flores, FMH's director, said in a television interview.
The condition is called dicephaly monozygotic conjoined birth, and it occurs in only one out of 80,000 live births.
Doctors at the Philippine Heart Center said oxygen and medication has been keeping the girl – technically a pair of conjoined twins – in stable condition, but an underdeveloped heart threatens their life.
Their complexion turns dark whenever they cry because of a hole in one of the hearts.
"Eventually if one heart fails, the other one will be affected," said Dr. Flores.
Speaking to CBS News Friday, Dr. Ludgerio Torres, director of the Philippine Heart Center, completely ruled out any operation to separate the conjoined twins, but said doctors were optimistic that the girls could survive.
A scan confirmed that the baby on the left has a normal healthy heart.
The hole in the other baby's heart is believed to be correctable, but doctors are not in a hurry to operate as antibiotics and oxygen are helping keep the twins in a stable condition. More importantly, said Torres, "together, they help one another," with the healthy heart bolstering the other.
Torres said the babies were being fed intravenously, but they've also started bottle feeding. So far, their "sucking reflex has been wonderful," added the doctor.
For the Arciaga family, it would not have been a complete surprise to have twins. Both sides of the family have twin members.
But ultrasound images before the birth showed only one baby, so the couple did not expect twins, much less conjoined twins.
Salvador Arciaga, the father, earns a meager income as a cycle-taxi driver. He appealed to the public for financial assistance.
"Please help our baby. Please support us and help us extend their lives," he said.
The Arciagas could only hope that their twins end up like Abigail and Brittany Hensel of Minnesota, who for 19 years have been living with one body. They can walk, run, ride a bicycle, and even drive.
The Aguirre twins from the Philippines, who were joined at the head, underwent a series of surgeries at Montefiore Medical Center in New York City in 2004, and are now living normal, healthy, and physically separate lives.
But these are rare cases. According to the University of Maryland Medical Center, the overall survival rate of conjoined twins is somewhere between 5 and 25 percent.
Salvador and his wife remain hopeful that their daughters will survive.
"I hope she lives. Because if she does, we will do everything that we can to raise her well," said Salvador.