Nash Keen, born 133 days early, spent over six months in NICU and is thriving despite initial health concerns.

But in the last few weeks, this little fighter celebrated his first birthday and received his official designation as the world’s most premature baby from Guinness World Records. This isn’t a record that Nash’s parents, Randall and Mollie Keen, wanted to break, but they’re thrilled to have an extra reason to cheer for their son.

A baby born at 21 weeks' gestation in Iowa City, Iowa, has celebrated his first birthday, earning a Guinness world record for being the most premature baby.