A one-year-old boy born at just 21 weeks has been officially named the world’s most premature baby by Guinness World Records.

Nash Keen was born 133 days early at the University of Iowa Health Care Stead Family Children’s Hospital in Iowa City, Iowa, to parents Mollie and Randall Keen.

A typical pregnancy lasts 40 weeks, with babies considered premature if born before 37 weeks and “micro-preemies” if before 26 weeks. When he entered the world, baby Nash weighed just 10 ounces (283 grams) and measured 24 centimeters (9 inches) long.

Leading the team that saved Nash’s life was Dr. Patrick McNamara, a native of Ballina, County Mayo, who serves as division director of neonatology at the Stead Family Children’s Hospital.

Commenting on what he thought baby Nash’s chances of survival were after he was born, Dr McNamara said: “We never want the parents to lose hope, but many of them [the babies] are in an unreal situation, so we have to be very honest with them. I would have told his parents, ‘The chance is zero, but I hope I’m wrong and we will do everything we can to help him.’”

McNamara’s innovative approach to neonatal care, including the use of hemodynamics – an ultrasound-based technique that monitors blood flow and heart function – has been credited with improving outcomes for extremely premature infants.

Nash’s achievement surpasses the previous Guinness World Record held by Curtis Means, born at 21 weeks and 1 day in July 2020 at the University of Alabama at Birmingham’s Women and Infants Center.