You are here

Patterns of Developmental Change in Infants’ Nighttime Sleep Awakenings from 6 through 36 Months of Age

Infants with night-wakings were more likely to be boys, be breastfed, have a difficult temperament, come from a large family, have a depressed mother, be in a single-parent home, and/or attend fewer hours of non-parental child care; however, this tendency for more night-wakings tended to resolve by 18 months.

[popup title="Sample, Hypothesis, Variables Measured, Study Design" format= "Default hover" text='


  • N: 1,200
  • Subject Ages: 6, 15, 24 and 36 months
  • Location: United States, hospitals at 10 data collection sites
  • SES: 24% ethnic minority, 11% of mothers did not complete high school, 14% single mothers (groups not mutually exclusive)
  • Eligibility: Not available
  • Additional: The sample was not designed to be nationally representative. However, the sample was similar to families in the census tract records and the nation as a whole on key demographic variables (household income and ethnicity).


  1. Estimate the developmental trajectories of children’s sleep awakenings.
  2. Identify important variables associated with the developmental trajectories by examining relations of the trajectories with temperament, breastfeeding experiences, attachment security, health problems during infancy, and familial and environmental risk factors.
  3. Examine individual differences in sleep awakenings at specific points across infancy.

Variables Measured, Instruments Used

  • Number of nights per week with sleep awakenings - standardized interview
  • Sleep problems - the Child Behavior Checklist (CBCL 2-3; Achenbach, 1992)
  • Gender and birth weight - interview
  • Temperament - 39 items selected from the 55 items on the Infant Temperament Questionnaire (Medoff Cooper, Carey, & McDevitt, 1993)
  • Whether mother breastfeeds - mother report
  • Attachment quality - the Strange Situation
  • Child illnesses - mother report
  • Maternal depression - the Center for Epidemiological Studies Depression Scale (CES-D; Radloff, 1977)
  • Maternal sensitivity - semi-structured, videotaped, coded interactions
  • Maternal health - mother report
  • Spouse/partner in the home - mother report
  • Poverty - mother report
  • Child care - mother report




  1. The two groups of children identified in this study appear to represent meaningful and distinct longitudinal patterns with regard to the developmental course of sleep.
  2. Not only were the patterns of sleep awakenings empirically distinctive, but membership in the groups was predictable from child and family characteristics.
  3. On average, the children who were “becoming sleepers” (defined by more frequent night awakenings), compared with “sleepers” (defined by little evidence of elevated sleep awakenings at any point from 6 months to 3 years), were more likely to be male, be breastfed, have a more difficult temperament, come from a large family, have a depressed mother, have a mother without a spouse or partner and/or be in child care for fewer hours.
  4. Most of these differences resolved at 18 months.


  • Reliance on maternal report
  • Infants with many perceived awakenings may be perceived as having difficult temperaments.
  • Restricted sample: All infants were healthy at birth, and there were no twins, low birth-weight or premature infants.
  • Correlational study