The maturation of respiratory patterns in normal full term infants during the first six postnatal months. II: Sleep states and apnoea

Abstract

ABSTRACT. Four term healthy infants had their respiratory pattern monitored during a 2-hour afternoon nap period at monthly intervals up to six months of age. Apnoeas 4 seconds or more at 1 week expressed as a percentage of breaths were significantly more frequent in active sleep than quiet sleep (2.1% vs 0.6%) and increased at 2 months in both sleep states (8.0% and 8.5% respectively) due to the onset of periodic breathing. Apnoeas then decreased in frequency up to 6 months in both sleep states (3.8% and 0.8% respectively). In the first month a startle and/or sigh occurred in 78% of apnoeas in quiet sleep, and gross body movement in 72% of apnoeas in active sleep. Between 4 to 6 months all apnoeas in quiet sleep were preceded by a startle and/or sigh, in contrast to active sleep, where the incidence of gross body movement and apnoea decreased (49%) and apnoea alone increased (48%). These findings confirm a maturational change in the incidence and pattern of apnoea in normal infants from 1 to 6 months.