Intrinsic and extrinsic factors associated with night waking in 9-month-old infants.

This study examined relations between infant night waking and both daytime behaviors reflective of poor behavioral and emotional regulation (intrinsic factors) and parent behaviors that may contribute to infant night waking (extrinsic factors) in 41 infants. Mothers completed questionnaires and an infant sleep and crying diary. More time awake at night was related to separation distress, frequent daytime crying, dysregulation, co-sleeping with parents, breast feeding, and being put to bed asleep. More frequent waking was related to separation distress, frequent daytime crying, co-sleeping, and breast feeding. The combination of intrinsic and extrinsic factors predicted night waking better than behaviors from one category alone. Implications for parenting are discussed.