The relative influence of child and environmental characteristics on sleep disturbances in the first and second years of life.

The study was designed to explore the relationship between sleeping disturbance in early and late infancy and variables related to (1) prenatal and birth factors, (2) child characteristics such as sex and temperament, (3) sleeping and feeding practices, (4) background factors, and (5) maternal depression and family stress. Mothers were interviewed first when their infants were between the ages 4 to 15 months and then when their infants were between 15 and 27 months of age. Hierarchical multiple regression analyses were used to assess the relative influence of variables in predicting sleeping disturbances in the first and second years. Sleeping disturbances in the first year were not related to sleeping disturbances in the second year. However, sleeping practices were the strongest predictors of sleeping disturbances in both early and late infancy. Predictability was improved in the first year by the inclusion of the variable maternal employment and in the second year by the inclusion of variables related to parental sleep difficulties. Explanation for these findings and suggestions for future research are discussed.