title: Troubled sleep: Night waking, breastfeeding and parent-offspring conflict.
abstract: Disrupted sleep is probably the most common complaint of parents with a new baby. Night waking increases in the second half of the first year of infant life and is more pronounced for breastfed infants. Sleep-related phenotypes of infants with Prader-Willi and Angelman syndromes suggest that imprinted genes of paternal origin promote greater wakefulness whereas imprinted genes of maternal origin favor more consolidated sleep. All these observations are consistent with a hypothesis that waking at night to suckle is an adaptation of infants to extend their mothers' lactational amenorrhea, thus delaying the birth of a younger sib and enhancing infant survival.
authors.affiliation: Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA.
authors.forename: David
authors.initials: D
authors.lastname: Haig
keywords: breastfeeding; co-sleeping; evolutionary pediatrics; interbirth intervals; lactational amenorrhea; night waking