Kiwi University Hospital has allowed a baby weighing only 268 grams, the youngest baby in the world to survive despite his small size, to go home after spending months in hospital in Tokyo.
The baby was born in a caesarean section last August after failing to gain weight during pregnancy, and doctors feared his life was at risk.
The baby remained in the intensive care unit until it became 3.2 kilograms and the hospital was allowed to leave on February 20, said doctor Takeshi Aremitsu of the Department of Pediatrics at the university's medical school.
"I am grateful that he grew up this way, because I frankly was not sure about his survival," said the child's mother.
According to the University of Iowa's smallest-sized infants, the previous record weight was for a 274-gram baby born in Germany in 2009.
The record also states that the smallest baby was born and weighs 252 grams in Germany in 2015