World's tiniest baby boy has grown enough to go home

TOPSHOT - This undated handout released by Japan's Keio University Hospital on February 27, 2019 shows a five-day-old baby, who weighed 268 grams at birth, at the hospital in Tokyo. - A baby born in Tokyo weighing less than 300 grams (10 ounces) has gone   -  Copyright  Keio University Hospital via AFP - Getty Images
By Meghan Holohan  with TODAY Lifestyle

He's not even a year old but already he's a record-breaker. This baby boy, who weighed 9.45 ounces when he was born in a Tokyo hospital, has the distinction of being the world's tiniest living baby boy, according to a report by Reuters.

"I wasn't sure he could survive," the baby's mom told Reuters.

Keio University Hospital
A baby born in Tokyo weighing less than 300 grams (10 ounces) has gone home healthy, become the smallest newborn boy in the worldKeio University Hospital

In August, his mom gave birth to him via Caesarean-section. He had stopped developing and doctors worried that he would not live. After his birth, he stayed in the neonatal intensive care unit until Feb. 20. When he left the hospital, he weighed more than 7 pounds (3.2 kilograms).

"I am grateful that he has grown this big," his mom said to Reuters.

Keio University Hospital

The University of Iowa's Tiniest Babies registry tracks record-holding little babies and noted that a German-born baby, weighing 9.66 ounces at birth in 2009, previously held the record of being the smallest surviving baby boy. The smallest surviving baby girl weighed 8.8 ounces when she was born in Germany in 2015.