Infant Sleep in the First 3 Months of Life Is Characterized by Frequent Night Waking, Necessary to Allow Feeding to Meet the Nutri-

566 INFANT SLEEP IN THE FIRST 3 MONTHS OF LIFE IS CHARACTERIZED BY FREQUENT NIGHT WAKING, NECESSARY TO ALLOW FEEDING TO MEET THE NUTRITIONAL demands of rapid growth. The remainder of this first year of life is a critical period for maturation of sleep, characterized by a gradual increase in nocturnal sleep and a reciprocal decrease in diurnal sleep. During this latter period, some infants begin to self-soothe after spontaneous night wakings.1 Failure to self-soothe and frequent disruptive night waking is clinically relevant for several reasons. Firstly, frequent night waking in later infancy predicts sleep problems at 3 years of age, which, in turn, are associated with behavioral problems.2 Suboptimal sleep quality may also impair learning, an important consideration in early childhood development.3 Finally, infant night waking disrupts parental sleep; evidence shows that maternal sleep disturbance predicts maternal mood, stress, and fatigue.4 Maternal depression following pregnancy has been linked with an increased risk of infant and childhood sleep problems, although lack of longitudinal data has limited our understanding of direction of effects. However, recent evidence from the Avon Longitudinal Study of Parents and Children (ALSPAC) suggests that maternal anxiety and depression during pregnancy are associated with an increased risk of infant sleep problems at 18 and 30 months of age.5 It is not clear whether maternal mental health problems that predispose to infant sleep problems are present prior to pregnancy. We have examined the relationship between preconceptional psychological distress and sleep problems during infancy in the Southampton Women’s Survey (SWS)—a population-based study of women surveyed before pregnancy and followed up after the birth of their baby.