What Do We Do When Limits of Viability Shift?

In medicine, neonatology is a relatively new specialty.In the 1940s, the expected outcome of any infant with a birthweight less than 1500 g was death, 1 and it wasn't until 1960 (65 years ago) that the term neonatology was coined. 2 As neonatologists, we care for sick newborn infants, including those born prematurely.As our field has developed, so has our ability to care for younger and more immature patients.In 1963, Patrick Kennedy-the youngest child of President John F. Kennedy and Jacqueline Kennedy Onassis-died from prematurity at 34 weeks' gestational age, yet by 1971, the Schaffer and Avery textbook Diseases of the Newborn stated that "the lower limit of viability is probably about 28 weeks" due to advances in respiratory therapies, thermoregulation, and nutrition 3 By the 1990s, large prospective cohort studies demonstrated a 50% survivability at 24 weeks' gestational age, 1 and recently centers have shown greater than 60% survivability in infants born at 22 weeks' gestational age. 4 Hyland et al 5 have provided data on a cohort of infants at the University of Iowa born at 21 weeks of gestation.In the study, the authors determined that during their 15-year study period, 252 infants were delivered at 21 weeks.Of those, 22 infants (9%) were born alive, and 17 survived to be admitted.Using care developed from protocols to treat 22-week infants, 6 of the 17 infants, or 35%, were successfully discharged home.