Background. Apnea of prematurity remains among the most commonly diagn
osed conditions in the Newborn Intensive Care Unit and may prolong hos
pital stays in some infants. Because survival of extremely premature i
nfants has improved markedly, the natural history of apnea in this pop
ulation needs to be reassessed. Objective. To document the natural his
tory of recurrent apnea and/or bradycardia events in infants delivered
at 24 to 28 weeks' gestation. Methods. Medical records of all infants
delivered at 24 to 28 weeks' gestation admitted to the Brigham and Wo
men's Hospital Newborn Intensive Care Unit between January 1989 and Ma
rch 1994 were reviewed to document the clinical course of apnea of pre
maturity. Subjects were included in the study sample if they were disc
harged home from the Brigham and Women's Hospital or after transfer to
an affiliated hospital. Recordings of apnea and/or bradycardia events
were based on nursing observations of monitor alarms and assessment o
f the infant's condition. Results. Of 457 eligible infants, 226 were i
ncluded in the study sample and stratified by gestational age at birth
assigned by the attending neonatologist. The time to resolution of re
current apnea/bradycardia events was longer with lower gestational age
at birth. Apnea/bradycardia events were frequently observed beyond 36
weeks' postconceptional age in all gestational age groups. The incide
nce of apnea persisting beyond 38 weeks postconceptional age was signi
ficantly higher in the 24- to 27-week infants combined compared with t
he 28-week infants. Conclusions. Apnea of prematurity frequently persi
sts beyond term gestation in infants delivered at 24 to 28 weeks' gest
ational age. These persistent apnea and/or bradycardia events may cont
ribute to prolonged hospitalization. Programs to promote earlier disch
arge of premature infants should take into account the variability in
resolution of apnea and specifically address management of persistent
apnea.