By means of polygraphic sleep recording, the sleep apnea profile with respect to the number and duration of inactive, obstructive and mixed apneic episodes as well as periodic breathing has been investigated in infants born preterm at 40, 52 and 64 weeks conceptional age and compared to that of term infants. At 40 weeks preterm infants showed significantly more apnea and periodic breathing compared to term infants. The difference was essentially due to obstructive and mixed apnea in non-REM sleep. There was a sharp decrease in all apneic variables--inactive, obstructive and mixed apnea as well as of periodic breathing--at 52 weeks conceptional age in infants that were previously preterm. Both groups exhibited a rather identical sleep apnea profile at 64 weeks. Two prospectively studied infants in the preterm group later became SIDS victims. One of them might have been identified as being at risk on the basis of his apnea profile compared to the normative data now available.
