Infant sleep and the quality of family life for first-time parents of three-month-old infants

This paper focuses on Phase 2 of this study when the infants were 3 months of age. At this time, mothers and fathers completed self-report measures of depressive symptoms, marital satisfaction, parenting stress, infant temperament and family functioning. During a home visit, parents participated in a joint interview regarding their infants' behavior and their experiences of parenthood.

Measures

Infant sleep. During the home-based interview, parents were interviewed together regarding their infant's sleep behaviors. They were asked to provide information on the longest duration of night-time sleep (in hours) that their infants obtained in a typical night. This question resulted in one infant sleep duration score per family and was coded according to the number of hours in half-hour intervals. For example, if parents reported that their child usually slept from 11:00 p.m. until 6:30 a.m. the following morning without waking (e.g., seven and one-half hours), an infant sleep score of 7.5 was assigned.

Depressive symptomatology. Parental depressive symptoms were assessed using the Beck Depression Inventory-II (BDI-II; Beck, Steer, & Brown, 1996). This scale has 21 items scored on a 4-point scale. Prior research has demonstrated the clinical utility of this measure (Beck et al.; Krefetz, Steer, Gulab, & Beck, 2002). In the current study, the internal reliability of the BDI-II was [alpha] = .85.

Parenting stress. Parenting stress was assessed using a modified version of the Parenting Daily Hassles Inventory (PDH; Crnic & Booth, 1991; Crnic & Greenburg, 1990). The 20 items on this scale are scored on a 4-point scale reflecting the frequency of a stressor's occurrence and a 5-point scale reflecting the intensity of the stressor. Since the PDH was initially developed for use with families with children up to 5 years of age, the scale was modified to better reflect the specific stresses associated with caring for an infant. One item was retained verbatim from the original ("Babysitters are difficult to find"), fourteen items were modified to reflect its use with babies (e.g., "Difficulty in preparing feedings or getting your baby to eat") and five items were dropped and replaced with more applicable items (e.g., "Getting up during the night with your baby", and "Worrying about your baby's health"). For the purposes of our analyses, we utilized participants' intensity scores as our measure of parenting stress. The range of possible intensity scores is 0-100 with higher scores indicating that a parent is experiencing greater pressure over parenting (Crnic & Booth). In the current study, the internal consistency for intensity was [alpha] = .86.

Infant temperament. Infant temperament was assessed using the Infant Characteristics Questionnaire (ICQ; Bates, Freeland & Lounsbury, 1979). This 24-item measure is rated on a 7-point scale relating to the parents' perceptions of their infant. Overall scores on the Fussy/Difficult subscale (e.g., "How easy or difficult is it for you to calm or soothe your baby when he/she is upset?") were used in this study to assess infant negativity. The internal reliability of this subscale in the present study was [alpha] = .83.