The emergence of a circadian pattern in respiratory rates: comparison between control infants and subsequent siblings of SIDS.

The objective of the present study is to compare the emergence of a circadian respiratory pattern in subsequent siblings of SIDS and controls infants to see whether the unique time and age of SIDS is correlated with altered circadian manifestations. During the first three months of life, a pattern in respiratory rates emerged which appeared to be the nightly portion of a circadian rhythm. Subsequent siblings of SIDS exhibited transient accelerated maturation of this circadian pattern. During the first month of life, minima in respiratory rates in quiet sleep occurred during the second and third intervals of the night in subsequent siblings, a pattern not seen until three months of age in control infants.