Polygraphic Studies of Normal Infants During the First Six Months of Life: III. Incidence of Apnea and Periodic Breathing

Abstract

The incidence of apnea and periodic breathing was studied in full-term infants between birth and 6 mo. of age. Apnea was defined as a pause equal to or exceeding 6 s, periodic breathing as 2 cessations of breathing within a 20-s period, each equal to or longer than 3 s but less than 6 s. Sleep and cardiopulmonary variables were monitored. Apnea was common in the normal full-term infant. The incidence of apnea was highest in the newborn period and apneas exceeding 15 s were limited to this age. A reduction in apnea incidence occurred between birth and 3 mo. of age; thereafter, the incidence remained unchanged. The majority of apneas occurred during active sleep (AS). Few minutes were classified as indeterminate; the number of apneas during these minutes was comparable to those during AS. The incidence of apneas during quiet sleep was low. Periodic breathing remained stable across the ages, occurring primarily in AS. Apnea exceeding 15 s is rare in infancy. The tabulation of shorter apnea may be of limited value in identifying infants at risk for abnormal apnea due to extreme variability among infants. The sleep-waking state of the infants must be considered in order to evaluate apnea counts.