By James J. McKenna, Ph.D. Throughout human history, breast-
feeding mothers sleeping alongside their infants constituted a
marvelously adaptive system in which both the mothers' and
infants' sleep physiology and health were connected in
beneficial ways. By sleeping next to its mother, the infant
receives protection, warmth, emotional reassurance, and breast
milk - in just the forms and quantities that nature intended.
This sleeping arrangement permits mothers (and fathers) to
respond quickly to the infant if it cries, chokes, or needs its
nasal passages cleared, its body cooled, warmed, caressed,
rocked or held. This arrangement thus helps to regulate the
infant's breathing, sleep state, arousal patterns, heart rates
and body temperature. The mother's proximity also stimulates the
infant to feed more frequently, thus receiving more antibodies
to fight disease. The increased nipple contact also causes
changes in the mother's hormone levels that help to prevent a
new pregnancy before the infant is ready to be w