Nash Keen, who turned 1 in July, has already set a Guinness World Record. Keen was born at 21 weeks last year as the world’s most premature baby. Let’s take a closer look at how the infant overcame th

Although most studies measuring premature-baby outcomes start at 22 and 23 weeks — reporting U.S. survival rates between 10 and 20 percent at that gestation — University of Iowa Health Care is among the few hospital systems that take on babies at 21 weeks.