Indian doctors performed a critical heart surgery on a premature baby boy who was the size of a palm at the time of birth and had underdeveloped organs and skin. He weighed only 474 grams following birth.

The infant suffered from a condition in which the aorta and pulmonary artery – the two main blood vessels of the heart – were connected. The corrective operation was performed 15 days after the child's birth by a team of expert doctors at Geetanjali Medical College & Hospital and Jeevanta Hospital in Udaipur city in the western state of Rajasthan.

The baby, still unnamed, was conceived through an IVF procedure and was born prematurely after 28 weeks. His skin was like parchment paper and the underdeveloped body was very fragile.

Following the surgery that lasted half an hour, the child's health condition is said to have improved. He now weighs around 600 grams, but is still kept in the intensive care unit.

Doctors said they conducted the surgery in the neonatal care unit where the child was kept since birth to prevent risks of moving the fragile child to an operation theatre. Special miniaturised surgical equipments were used for the baby.

"Operating on an infant, especially when he is so tiny, is very challenging and risky as the body parts are extremely premature," cardiovascular and thoracic surgeon Dr Sanjay Gandhi told the Times of India. "There were many risks involved like respiratory distress syndrome, brain/lungs internal bleeding, feeding intolerance, developmental problems, etc., and above all survival rate up to 55% only."

"The baby had very weak muscles, rib cage and almost all the body parts were very weak. It was like walking on a tight rope but we succeeded," Dr Sunil Jangid, chief neonatologist and paediatric intensivist at the Udaipur hospital, said.

The parents were extremely worried throughout the procedure and were praying for their baby's health.

"We still haven't thought of a name for our son. It is no less than a miracle. He is so brave that he has survived so many odds with such low weight being a pre-term neonate. Our prayers are answered," the teary-eyed parents told the publication.

The baby is possibly the world's tiniest to have undergone such a critical surgery. Gandhi said he had successfully performed a vital surgery on a newborn baby weighing only 700 grams at a hospital in the state capital of Jaipur in 2016.

Another premature baby born after a little over 27 weeks weighing 550 grams survived a surgery in 2014 at Kokilaben Ambani Hospital in Mumbai – the financial capital of India.

A 24-week-old premature baby weighing 489 grams also experienced the same in Medicana International Hospital in Istanbul, Turkey, in 2016.