Most premature baby

The most premature baby is Nash Keen, who was born to Mollie and Randall Keen (all USA) at 9.51 a.m. on 5 July 2024 at University of Iowa Health Care in Iowa City, Iowa, USA, at a gestational age of exactly 21 weeks, or 147 days, making him 133 days premature.

Nash’s delivery was performed by Drs Malinda Schaefer and H Bennett Stevens and attended by neonatologist Dr Amy Stanford, who supervised Nash’s resuscitation. He weighed just 285 g (10 oz) and measured 24 cm (9.5 in) long.

After some six months being cared for at the hospital’s NICU (neonatal intensive care unit), Nash was discharged and allowed to return home in early January 2025. He celebrated his first birthday in the family's home city of Ankeny, Iowa, on 5 July 2025.

The standard gestational period for a full-term baby is 40 weeks (280 days).

Nash surpassed the previous record by one day: Curtis Zy-Keith Means (USA) was born to Michelle Butler on 5 July 2020 at the University of Alabama at Birmingham Hospital in Alabama, USA, at a gestational age of 21 weeks 1 day, or 148 days, making him 132 days premature.