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

While it is widely recognized that sleep patterns in early infancy can affect the quality of family life, studies have focused primarily on sleep problems that emerge in later infancy. Further, researchers have tended to conceptualize the quality of family life primarily in terms of the psychological functioning of the mother and have thus ignored the experiences of fathers. Grounded in a family systems framework, this study explores the relationship between nighttime infant sleep duration, infant negativity, psychological and relational functioning in first-time parents of three-month-old infants. Infant sleep duration was significantly associated with father's reports of parenting stress, family functioning and infant negativity. Infant sleep duration was related to fathers' psychological functioning with fathers whose infants slept for shorter periods reporting higher levels of distress than fathers whose infants slept for longer periods of time. Contrary to expectations, neither mothers' psychological functioning, nor mothers' or fathers' ratings of relational functioning were significantly associated with infant sleep duration. These results highlight the importance of studying the influences of normal infant behaviors on new parents and of expanding the study of early infant development beyond a focus on the mother-child dyad.

Keywords: fathers, mothers, infant sleep, psychological functioning, family relationships

**********

One of the most commonly cited concerns of new parents is their infants' sleep behaviors (Ferber, 2006; Thiedke, 2001; Thome & Skuladottir, 2005a, 2005b; Wolfson, Lacks, & Futterman, 1992). While anecdotal evidence suggests this concern may reflect the negative associations between infant sleep and the quality of family life, these associations have received little empirical attention (Durand & Mindell, 1990; Thome & Skuladottir, 2005a). Moreover, in the few studies that have been conducted, researchers have focused primarily on associations between sleep problems in late infancy and maternal psychological functioning. This narrow focus is problematic for at least two reasons. First, parental complaints about their infants' sleep often occur during the first few months of infancy, and reflect experiences with normal, not abnormal, sleep behaviors (Ferber). Second, by focusing primarily on the relationship between infant sleep and maternal psychological functioning, researchers are ignoring not only the associations between infant sleep and the psychological functioning of fathers, but also its associations with other aspects of the family functioning, such as dyadic and family unit functioning. Researchers have indicated that the functioning of families is best understood from a family systems perspective, which takes into account not only functioning at the level of individual family members, including mothers and fathers, but also functioning at the level of family relationships (i.e., marital dyads, family-unit) (Barrows, 2004; Hayden et al., 1998). Thus, in order to develop a comprehensive understanding of the relationship between infant sleep and the quality of family life, we need to expand our investigations to examine associations between normal infant sleep behaviors in early infancy and the quality of family life at different levels within the family system. In this study, we investigated the relationships between infant sleep, parental psychological functioning, and relational functioning in first-time parents of 3-month old infants.

Infant Sleep and Parental Psychological Functioning

During the first month of infancy, most infants awaken every 3-4 hours and require caregivers to settle them back to sleep (Middlemiss, 2004; Wolfson et al., 1992). These frequent night-wakings, which impact the duration of night sleep, tend to reduce in frequency during the first year (Goodlin-Jones & Anders, 2004). Researchers have found the longest period of infant sleep duration increases steadily from birth until around 3 months of age, when it levels out and tends to remain stable for the remainder of the first year (Burnham, Goodlin-Jones, Gaylor, & Anders, 2002). However, there remains a wide range of variability at the three-month age period, with the majority of non-clinical three-month-old infants sleeping anywhere from 5 to 9 hours during the night without waking. Despite the wide range of normal sleep duration at this age, patterns of sleep behavior do not come to be clinically recognized as sleep problems until the infant is at least six months old. As researchers interested in infant sleep and family life have understandably focused on families of infants with recognized sleep problems (Goodlin-Jones & Anders), studies have generally been done with infants six months old or older. Nevertheless, the specifics of a given infant's sleep behavior probably make a difference to that infant's parents. For example, it is likely that parents of an infant who is sleeping 5 hours or less at a time may view their infant's sleep as more problematic than the parents of an infant who is sleeping 9 hours or more at a time, despite that both 5 and 9 hours are considered to be in the normal range. The common recognition that a relative lack of night-time sleep during early infancy may be negatively associated with the quality of family life is reflected in one of the questions most frequently asked of parents of newborns, "Is your baby sleeping through the night yet?" Findings from large-scale epidemiological surveys also support this view. Approximately 15% of parents of 3-month-old infants report their infants' sleep as problematic (Thome & Skuladottir, 2005a), even though it is not clinically recognized as a sleep problem at this stage. Thus, given that this variation in normal infant development is of concern to some parents, extending the examination of infant sleep on the quality of family life to early infancy is warranted.

As highlighted above, the majority of research on infant sleep and the quality of family life has focused on sleep problems in later infancy and their relationship to maternal psychological functioning. Researchers have found infant sleep problems to be associated with higher levels of maternal depressive symptoms (Armstrong, O'Donnell, McCallum, & Dadds, 1998; Dennis & Ross, 2005; Hiscock & Wake, 2001) and higher levels of maternal stress (Durand & Mindell, 1990; Thome & Skuladottir, 2005b). In their community-based, large-scale study of mothers of 6- to 12-month old-infants, Hiscock and Wake found that infant sleep problems were strongly associated with maternal depressive symptoms even when other risk factors for depression were taken into account. Mothers whose infants have been clinically identified as having sleep problems report higher rates of depressive symptoms (Armstrong et al.; Thome & Skuladottir) and stress (Thome & Skuladottir) than mothers of similar aged infants without sleep problems. Clinical intervention studies have demonstrated that treatment for sleep problems in infancy leads to a reduction in maternal reports of depressive symptoms and stress (Durand & Mindell; Thome & Skuladottir).

Researchers who have included fathers in their studies of child behaviors and parental functioning have consistently found that fathers' experiences are similar to but also unique from mothers' experiences (Flouri, 2005). Given the small number of studies of infant sleep that have included fathers, it is difficult to determine whether that pattern holds true in this context as well. Information on the associations between infant sleep and the psychological functioning of fathers comes primarily from clinical intervention case studies. Mothers and fathers have been found to report similar levels of depressive symptoms and stress in cases where their infants were identified as needing sleep intervention (Thome & Skuladottir, 2005b), and to show comparable decreases of depressive symptoms after intervention for infant sleep problems (Durand & Mindell, 1990; Thome & Skuladottir, 2005b). Although they did not directly compare mothers and fathers in their follow-up study of parents whose children had been treated for sleep problems in infancy, Thome and Skuladottir (2005a) suggest one difference between mothers and fathers. Fathers whose infants had been identified as needing treatment for sleep problems reported higher levels of parenting stress, depressive symptoms and fatigue than a control group of fathers whose infants were not identified as needing such treatment. Mothers reported only higher levels of fatigue than the control group mothers. These findings highlight the importance of examining the psychological functioning of both mothers and fathers in our studies of infant sleep.

Infant Sleep and Relational Functioning

Despite anecdotal evidence that infant sleep can affect relationships at the level of the parental dyad and at the level of the family unit, few studies have empirically examined the associations between infant sleep and relational functioning. In their single case study, Durand and Mindell (1994) found an improvement in marital satisfaction for both the mother and the father following a sleep intervention with a 14-month old. In their large, community-based study of Australian parents, Lam, Hiscock, and Wake (2003) found that sleep problems were not associated with marital satisfaction or family unit functioning in mothers with 3-4 year olds. However, given that Earn et al. examined these relationships when the children were preschoolers, it is not clear how well these findings can be extended to infants. Moreover, their study did not include fathers. Given the anecdotal evidence to suggest that infant sleep does impact the quality of family life, studying its associations with relational functioning as well as individual psychological functioning allows us to provide a more comprehensive understanding of these relationships.

Infant Temperament, Infant Sleep, and the Quality of Family Life

Infant characteristics, such as having a more negative or difficult temperament, have been linked to sleep problems in infancy (Keener, Zeanah & Anders, 1988; Morell & Steele, 2003; Scher, Tirosh, & Lavie, 1998). Although the direction of the causal relationship is not clear, most studies have found associations between maternal ratings of more difficult infant temperaments and infant sleep problems such as night waking and short sleep duration (e.g., Morell & Steele; Scher et al.). Two studies were found that examined infant sleep and fathers' ratings of infant temperament. Atella, DiPietro, Smith, and St James-Roberts, (2003) found no association between duration of infant sleep and fathers' ratings of infant temperament in 6-week-old infants. However, Keener et al. (1988) found that although mothers and fathers were similar in their temperament ratings of their 6-month-old infants, fathers' ratings of infant negativity were more strongly associated with infant sleep than mothers' ratings. As infant negativity is linked to the psychological functioning of mothers (e.g., Cummings & Davies, 1994) and fathers (Atella et al.) as well relational functioning within the family (Durand & Mindell, 1994), it is an important variable to include in studies of infant sleep and the quality of family life.

In sum, the conceptual issues raised in the above literature review suggest a possible relationship between infant sleep and the quality of family life. In this study, we investigated the relationships between infant sleep, psychological functioning at the level of the individual (parental psychological functioning) and psychological functioning at the level of relationships within the family (relational functioning) in a non-clinical population of first-time parents with 3-month-old infants. We hypothesized that duration of night-time infant sleep would be associated with parents' ratings of infant negativity, and with parenting stress, depression, marital satisfaction and family functioning. Moreover, we hypothesized that infant sleep duration would account for unique variance in parental psychological functioning and relational functioning.

Method

Participants and Procedures

Couples in this study were enrolled in a longitudinal study following first-time parents from the third trimester of pregnancy until their infants' first birthday. Cohabiting couples expecting their first child were recruited from prenatal classes and a community baby shower in a western Canadian city. Of the 78 couples that began the study, 72 (92%) remained in the study to complete Phase 2 when their infants were 3 months of age. Mothers ranged in age from 18 to 40 years, with an average age of 28.7 years (SD = 5.4), while fathers ranged in age from 19 to 57 years, with an average age of 30.8 years (SD = 6.3). All of the couples were living together at the time of recruitment, with the majority of them legally married (86%). Compared to 2001 census data for the local population, our sample was slightly better educated (79.2% versus 62% had some post-secondary education), had comparable income levels with 2-parent families (average combined income over $60,000), and were of comparable ethnic origins (majority Caucasian).

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.

Marital satisfaction. Marital Satisfaction was assessed using the Dyadic Adjustment Scale (DAS; Spanier, 1976). A total DAS score reflecting overall relationship quality is obtained by summing responses to the individual items, with higher scores indicating greater satisfaction with the overall relationship. The validity and reliability of the DAS has been previously demonstrated (Spanier). For the current study the internal reliability was [alpha] = .92

Family-unit functioning. Family functioning was assessed using the Family Assessment Device (FAD; Epstein, Baldwin, & Bishop, 1983). This instrument provides a measure of overall quality of family functioning that was employed in this study. Higher scores on this measure reflect poorer family functioning. The internal reliability of this subscale was [alpha] = .90.

Data Analyses

First, descriptive analyses were conducted with the research variables. In order to reduce the number of variables in our regression analyses, two functioning indices were created from our raw data. Decisions for variable inclusion were made conceptually, based on prior research in this area (e.g., Miceli, Goeke-Morey, Whitman, Kolberg, Miller-Loncar, & White, 2000; Porter & Hsu, 2003). A psychological functioning index (PFI) was created separately for mothers and fathers by standardizing and summing individual ratings of parenting stress and depressive symptoms. Thus, for fathers, their PFI scores are the sum of their standardized ratings on the PDH and on the BDI-2. Maternal PFI scores were calculated in a similar fashion. Higher scores on this index reflect a greater degree of psychological distress. To assess relational functioning, a relational functioning index (RFI) was created by standardizing and summing individual ratings of family functioning and marital satisfaction for each parent. Family functioning scores were reversed and then summed with marital satisfaction scores for each partner. Thus, for fathers, their RFI scores are the sum of their standardized ratings on the FAD and on the DAS. Maternal RFI scores were calculated in a similar fashion. Higher scores on this index reflect a greater satisfaction with their marital and family relationships. These indices were then used for the regression analyses.

Results

Preliminary Analyses

Descriptive analyses were conducted on all of the research variables (see Table 1). In terms of the longest duration of night-time sleep, infants in this study averaged 6.5 hours (SD = 2.3) and ranged from 1.5 hours to 11 hours. The distribution of hours of sleep duration was nearly normal (skewness = -.03). Given the possible lack of independence in our sample (i.e., mothers and fathers in the same families), repeated measures ANOVA's were conducted with parent gender as the within-group variable to assess whether mothers and fathers differed on their ratings of parenting stress, depressive symptoms, infant negativity, marital satisfaction, and family functioning. Mothers in our sample rated themselves higher on depressive symptoms than fathers, F(1,71) = 18.98, p = .001, partial [[eta].sup.2] = .21. Mothers and fathers also differed on their views of their general family functioning, with fathers rating their family as functioning more poorly than mothers, F(1, 71) = 5.62,p < .05, partial [[eta].sup.2] = .07.

In order to determine the relationships between infant sleep duration and the research variables (i.e., parent ratings of infant negativity, parenting stress, depressive symptoms, marital satisfaction, and family functioning), correlational analyses were performed (Table 2). Shorter durations of infant sleep were negatively associated with ratings of infant negativity for both fathers, r(70) = -.37; p < .01, and mothers, r(71) = -.24, p < .05. For fathers, higher levels of parenting stress and poorer family functioning were also associated with shorter infant sleep duration, r(67) = -.34; p < .01; r(71) = -.24; p < .05. Infant sleep duration was not associated with depressive symptoms or marital satisfaction for fathers. For mothers, no associations were found between infant sleep duration, and their ratings of parenting stress, depressive symptoms, marital satisfaction, or family functioning.

Associations between Infant Sleep Duration and Parental Psychological Functioning

Hierarchical regression analyses were conducted separately for mothers and fathers to examine the contributions of infant sleep duration to parental psychological functioning. Because demographic variables such of age and education have been correlated with psychological functioning and relational functioning in previous studies (Pascoe, Stolfi, & Ormond, 2006) these variables were entered into the regression model first. Next, given that psychological functioning of family members may not be completely independent of one another, in the maternal model, paternal PFI scores were entered on the second step, while in the paternal model, maternal PFI scores were entered on the second step. Given the established associations between psychological functioning and infant temperament, ratings of infant negativity were entered on the third step. Finally, infant sleep duration was entered on the fourth step to examine whether it accounted for unique variance in psychological functioning scores.

Bivariate correlations for the variables entered into the regression analyses can be found in Table 3. For fathers, infant sleep duration was negatively associated with the psychological functioning index, r(67) = -.33; p < .01, and the correlation between fathers' relational functioning and infant sleep duration approached statistical significance, r(71) = .21, p < .08. For mothers, infant sleep duration was not associated with either the psychological or relational functioning indices. Mothers' and fathers' ratings of psychological functioning, r(66) = .48, p < .01, and relational functioning, r(71) = .66, p < .01, were also associated with each other.

The summary of results for each equation is listed in Table 4. For fathers, the overall model was statistically significant, F(5, 61) = 7.07, p <.001, accounting for 32% of the variance. Consistent with our hypothesis, infant sleep duration accounted for a unique amount of variance (i.e., 7%) in fathers' psychological functioning over and above the contributions of our control variables. Maternal psychological functioning ([beta] = .47), and infant negativity ([beta] = .25) were also predictors of fathers' psychological functioning. For mothers, the overall model was statistically significant, F(5, 61) = 7.30, p <.001, and accounted for 32% of the variance. Contrary to predictions, infant sleep duration did not contribute to the model for mothers ([beta] =. 16). Maternal age ([beta] = -.31), paternal psychological functioning ([beta] = .45), and infant negativity ([beta] = .27) were significant predictors of parenting stress.

Associations between Parental Relational Functioning and Infant Sleep

Regression analyses were conducted to examine the contributions of infant sleep duration to parents' relational functioning (Table 5). Following the previous analyses, parent age and education were entered on the first block, relational functioning of the opposite sex parent was entered on the second block, ratings of infant negativity were entered on the third block and infant sleep duration was entered on the final block. Contrary to expectations, infant sleep duration was not a statistically significant predictor of relational functioning for either parent. For father's, the overall model was statistically significant, F(5,65) = 11.87, p < .001, and accounted for 44% of the variance. Maternal relational functioning ([beta] = .65) and infant negativity ([beta] = -.20) were statistically significant predictors of fathers' relational functioning. For mothers, the overall model was statistically significant, F(5, 66) = 11.58, p <.001, and accounted for 43% of the variance. The only statistically significant predictor of maternal relational functioning was paternal relational functioning ([beta] = .65).

Discussion

This study was designed to extend our understanding of infant sleep and the quality of family life for first-time parents. It expands on existing knowledge by extending the examination of infant sleep behaviors beyond sleep problems, by studying these behaviors in early infancy, and by including the experiences of fathers. Moreover, this study provides a significant contribution to our understanding of men's experiences in families by indicating that the association between infant sleep and psychological functioning may differ for fathers and mothers.

Infant Sleep and Infant Negativity

Our hypothesis that duration of infant night-time sleep would be associated with parents' ratings of infant negativity was supported. Shorter infant sleep duration in 3-month-old infants was associated with higher ratings of infant negativity for both fathers and mothers. These findings extend previous research that relates infant negativity to sleep behaviors in older non-clinical infants (e.g., Keener et al., 1988). The associations between sleep behaviors in non-clinical infants and parents' ratings of temperament highlight of the importance of studying normal sleep behaviors in early infancy as there is a large body of literature linking parents' perceptions of negative infant temperament with parenting behaviors (Paulussen-Hoogeboom, Stams, Hermanns, & Peetsma, 2007) and parent-infant relationships. Further, as our findings establish an association not only between infant sleep and negative temperament but also between infant sleep and fathers' psychological functioning, future studies need to address the possible mediating effect that temperament may exert between psychological functioning and infant sleep.

Infant Sleep and Psychological Functioning

Our hypothesis that duration of night-time infant sleep would be associated with parents' psychological functioning received partial support. Fathers whose infants sleep for shorter stretches during the night rate themselves higher on parenting stress than fathers whose infants sleep for longer stretches. These results extend findings from clinical intervention studies that demonstrated fathers' parenting stress levels decreased following sleep interventions for their infants (Durand & Mindell, 1990; Thome & Skuladottir, 2005a). Providing further support for the link between infant sleep and fathers' psychological functioning, infant sleep duration was found to be a predictor of fathers' ratings of psychological functioning even when other related factors, such as infant negativity and maternal psychological functioning, were taken into account.

Contrary to expectations, neither paternal nor maternal depressive symptoms nor maternal parenting stress were associated with infant sleep. This is contrary to previous research that has consistently found infant sleep to be related to maternal depressive symptoms and parenting stress, and intervention studies that have linked treatment for infant sleep problems to decreases in depressive symptoms and stress for fathers. This unexpected finding may reflect that although correlations have been found between these variables, the mechanisms through which infant sleep problems are linked to depressive symptoms and stress have not been articulated.

One way that sleep problems in infancy might lead to depressive symptoms is through parental expectations of their abilities to manage or influence these behaviors. Given the pervasive talk about the detrimental aspects of infant sleep, it may be that first-time parents expect their newborns and young infants to be poor sleepers and thus do not internalize these behaviors as evidence of their success or failure as parents. However, if their infant's sleep behaviors do not seem to get better over time, parents may begin to see these behaviors as reflective of their parenting skills. Future research could assess whether parents hold themselves responsible for their infants' poor sleep patterns to a different degree as infants get older, and whether the degree of responsibility they believe they have for negative outcomes is linked to depressive symptoms and parenting stress.

The mechanisms through which infant sleep is connected to parental stress are also not clearly identified in the literature. In this study, infant sleep behaviors were related to fathers' but not mothers' levels of parenting stress. There are a number of possible explanations for this finding. First, it may be that fathers' ratings of parenting stress are more influenced by infant sleep patterns than mothers due to their employment outside of the home. In our study, all of the mothers were at home with their infants fulltime, while the majority of the fathers in this study were employed outside of the home. (1) As mothers are often encouraged to sleep when the baby is sleeping, those whose infants are not sleeping as long during the night may have the opportunity to catch up on their sleep during the day, while the fathers who are working full-time do not have that opportunity. As lack of sleep has been linked to stress in other contexts (Stepanski, 2006) the relationship between fathers' parenting stress and their infants' sleep may reflect the fathers' lack of sleep.

Another possible explanation for the association between infant sleep and fathers' parenting stress involves the notion of role strain. As the majority of the fathers in this study were employed outside of the home, they were balancing the needs of their employment with the needs of their family. While some scholars suggest there are beneficial effects of maintaining dual roles of worker and parent, beyond certain upper limits, role overload and distress may occur (Barnett & Hyde, 2001). The transition to parenthood, through placing additional demands on men, may be one of those times when such upper limits are tested. As responsibilities within the home are increasing, with men familiarizing themselves with the role of new father (Cowan & Cowan, 2003), the role of financial provider also becomes especially salient (Christiansen & Palkovitz, 2001). Thus, many men increase the hours spent in paid labor (Knoester & Eggbeen, 2006), at the same time they experience an increase in work to be done in the home. Add to this that workplace cultures and policies have been slow to change in ways that encourage paternal involvement in the family (Daly, 2004) and the situation becomes fraught with possibilities for role overload and distress. Clearly more research is needed to explore the links between infant sleep behaviors, personal and role expectations and psychological distress.

The strongest predictor of psychological functioning for both mothers and fathers was the psychological functioning of the opposite sex parent. This finding lends support for the use of a family-systems approach to the study of infants, as the psychological functioning of mothers and fathers in this study is clearly interdependent. Finally, consistent with prior research, maternal age was predictive of mothers' psychological functioning with younger mothers reporting higher levels of psychological distress (Pascoe et al., 2006). Contrary to findings linking mental health to education (Bronte-Tinkew, Moore, Matthews, & Carrano, 2007), educational levels were not associated with mothers' or fathers' psychological functioning in this study. This may be due to the lack of range in educational levels in this sample with the majority of parents being well-educated.

Infant Sleep and Relational Functioning

Our hypothesis that infant sleep would be associated with relational functioning also received partial support. For fathers in this study, there was an association between infant sleep behaviors and their ratings of family functioning. Fathers' whose infants slept for shorter durations rated their families as functioning more poorly than fathers whose infants slept for longer durations. This may again reflect role strain, as fathers may feel that they are not able to manage their roles as effectively as they would like, and thus rate their family functioning as more poorly. Further support for this comes from the finding that fathers rated their families as functioning more poorly than mothers did. Contrary to expectations, infant sleep was not related to marital satisfaction for either fathers or mothers. More research is needed to advance our understanding of these findings.

Conclusions and Limitations

This study highlights the need to broaden the study of the relationships between infant sleep behaviors and the quality of family life. These results underscore the importance of studying normative family transitions, and normal infant development (Walsh, 1998). They also underlie the importance of including fathers in studies of infant sleep behaviors. Clear differences emerged between mothers and fathers in this study, with infant sleep duration related to fathers' but not mothers' psychological functioning. These differences support the concerns of previous researchers who recommend using caution when generalizing the experiences of mothers to those of fathers. Furthermore, our results support the notion that we must expand the study of early infancy to include the perceptions and experiences of fathers. Since the fathers in our study were all balancing the demands of their employment with their new family reality, future research must examine whether the balancing of these dual roles may partly explain differing associations with parenting stress. More importantly, however, these findings provide empirical support for the relationship between infant sleep and the quality of family life. As variations in sleep behaviors in early infancy are considered normal, researchers and clinicians tend to wait until infants are older to identify and intervene with sleep problems. The findings that fathers whose infants slept for shorter time periods during the night rate their infants as more negative, rate themselves higher on psychological distress, and rate their families as functioning more poorly suggests that we should not wait to address these issues.

This study is not without limitations. First, the majority of parents in our study were well-educated, had moderate to high levels of family income, and were Caucasian. This decreases the generalizability of our results. Second, our reliance on parent self-report measures may have given rise to shared method variance and thus influenced our results. Finally, our measure of infant sleep duration relied strictly on parents' shared judgments. Future research should include objective as well as subjective measures of infant sleep and family functioning to assess the accuracy of parents' perceptions. In addition, including parents' reports of their own sleep behaviors and fatigue would add another layer of complexity to the analyses and may further inform our understandings. Finally, future research with larger sample sizes could utilize multilevel modeling techniques to account for the possible lack of independence of mothers' and fathers' reports in the same families.

References

Armstrong, K.L., O'Donnell, H., McCallum, R., & Dadds, M. (1998). Childhood sleep problems: Association with prenatal factors and maternal distress/depression. Journal of Paediatrics and Child Health, 34, 263-266.

Atella, L.D., DiPietro, J.A., Smith, B.A., & St James-Roberts, I. (2003). More than meets the eye: Parental and infant contributors to maternal and paternal reports of early infant difficultness. Parenting: Science and Practice, 3, 265-284.

Barnett, R.C., & Hyde, J.S. (2001). Women, men, work, and family. American Psychologist, 56, 781-796.

Barrows, P. (2004). Fathers and families: Locating the ghost in the nursery. Infant Mental Health Journal, 25, 408-423.

Bates, J.E., Freeland, C.B., & Lounsbury, M.L. (1979). Measurement of infant difficultness. Child Development, 50, 794-803.

Beck, A.T., Steer, R.A., & Brown, G.K. (1996). Manual for the Beck Depression Inventory-II. San Antonio, TX: Psychological Corporation.

Bronte-Tinkew, J., Moore, K.A., Matthews, G., & Carrano, J. (2007). Symptoms of major depression in a sample of fathers of infants: Sociodemographic correlates and links to father involvement. Journal of Family Issues, 28, 61-99.

Burnham, M.M., Goodlin-Jones, B.L., Gaylor, E.E., & Anders, T.F. (2002). Nighttime sleep-wake patterns and self-soothing from birth to one year of age: A longitudinal intervention study. Journal of Child Psychology and Psychiatry, 43, 713-725.

Christiansen, S.L., & Palkovitz, R. (2001). Why the "good provider" role still matters. Journal of Family Issues, 22, 84-106.

Cowan, P.A., & Cowan, C.P. (2003) Normative family transitions, normal family processes, and healthy child development. In F. Walsh (Ed.), Normal family processes (3rd ed., pp. 424-459). New York: Guilford Press.

Crnic, K.A., & Booth, C.L. (1991). Mothers' and fathers' perceptions of daily hassles of parenting across early childhood. Journal of Marriage and the Family, 53, 1042-1050.

Crnic, K.A., & Greenberg, M.T. (1990). Minor parenting stresses with young children. Child Development, 61, 1628-1637.

Cummings, E.M., & Davies, P.T. (1994). Maternal depression and child development. Journal of Child Psychology and Psychiatry, 35, 73-122.

Daly, K. (2004). The changing culture of parenting. Contemporary family trends. Ottawa: The Vanier Institute of the Family.

Dennis, C., & Ross, L. (2005). Relationships among infant sleep patterns, maternal fatigue, and development of depressive symptomatology. Birth: Issues in Perinatal Care, 32, 187-193.

Durand, V.M., & Mindell, J.A. (1990). Behavioral treatment of multiple childhood sleep disorders: Effects on child and family. Behavior Modification, 14, 37-49.

Epstein N., Baldwin, L., & Bishop, D. (1983). The McMaster Family Assessment Device. Journal of Marital and Family Therapy, 9, 171-180.

Ferber, R. (2006). Solving your child's sleep problems: New, revised and expanded edition. New York: Simon & Schuster, Inc.

Flouri, E. (2005). Fathering and child outcomes. West Sussex: John Wiley & Sons.

Goodlin-Jones, B.L., & Anders, T F. (2004). Sleep disorders. In R. Del Carmen-Wiggins & A. Carter (Eds.), Handbook of infant, toddler, and preschool mental health assessment (pp. 271-288). Oxford, UK: Oxford University Press.

Hayden, L.C., Schiller, M., Dickstein, S., Seifer, R., Sameroff, A. J., Miller, I., Keitner, G., & Rasmussen, S. (1998). Levels of family assessment: I. Family, marital and parent-child interaction. Journal of Family Psychology, 12, 7-22.

Hiscock, H., & Wake, M. (2001). Infant sleep problems and postnatal depression: A community-scale study. Pediatrics, 107, 1-9.

Keener, M., Zeanah, C., & Anders, T. (1988). Infant temperament, sleep organization, and night-time parental interventions. Pediatrics, 81, 762-771.

Knoester, C., & Eggbeen, D.J. (2006). The effects of the transition to parenthood and subsequent children on men's well-being and social participation. Journal of Family Issues, 27, 1532-1560.

Krefetz, D.G., Steer, R.A., Gulab, N.A., & Beck, A.T. (2002). Convergent validity of the Beck Depression lnventory-II with the Reynolds Adolescent Depression Scale in psychiatric inpatients. Journal of Personality Assessment, 78, 451-460.

Lam, P., Hiscock, H., & Wake, M. (2003). Outcomes of infant sleep problems: A longitudinal study of sleep, behavior, and maternal well-being. Pediatrics, 111, 203-207.

Miceli, P.J., Goeke-Morey, M., Whitman, T.L., Kolberg, K., Miller-Loncar, C., & White, R. (2000). Brief report: Birth status, medical complications and social environment: Individual differences in development of preterm, very low birth weight infants. Journal of Pediatric Psychology, 25(5), 353-358.

Middlemiss, W. (2004). Infant sleep: A review of normative and problematic sleep interventions. Early Childhood Development and Care, 174, 99-122.

Morrell, J., & Steele, H. (2003). The role of attachment security, temperament, maternal perception, and care-giving behavior in persistent infant sleeping problems. Infant Mental Health Journal, 24, 447-468.

Pascoe, J.M., Stolfi, A., & Ormond, N.B. (2006). Correlates of mothers' persistent depressive symptoms: A national study. Journal of Pediatric Health Care, 20(4), 261-269.

Paulussen-Hoogeboom, M.C., Stams, G.J.J.M., Hermanns, J.M.A., & Peetsma, T.T.D. (2007). Child negative emotionality and parenting from infancy to preschool: A meta-analytic review. Developmental Psychology, 43, 438-453.

Porter, C., & Hsu, H-C. (2003). First-time mothers' perceptions of efficacy during the transition to motherhood: Links to infant temperament. Journal of Family Psychology, 17(1), 54-64.

Scher, A., Tirosh, E., & Lavie, P. (1998). The relationship between sleep and temperament revisited: Evidence for 12-month olds: A research note. Journal of Child and Psychiatrity, 39, 785-788.

Spanier, G.B. (1976). Measuring dyadic adjustment: New scales for assessing the quality of marriage and similar dyads. Journal of Marriage and the Family, 38, 15-28.

Stepanski, E.J. (2006). Causes of insomnia. In T. Lee-Chiong (Ed.), Sleep: A comprehensive handbook (pp. 99-102). Hoboken, NJ: John Wiley & Sons.

Thiedke, C. (2001). Sleep disorders and sleep problems in childhood. American Family Physician, 63, 277-284.

Thome, M., & Skuladottir, A. (2005a). Changes in sleep problems, parents distress and impact of sleep problems from infancy to preschool age for referred and unreferred children. Scandinavian Journal of Caring Sciences, 19, 86-94.

Thome, M., & Skuladottir, A. (2005b). Evaluating a family-centred intervention for infant sleep problems. Journal of Advanced Nursing, 50, 5-11.

Walsh, F. (1998). Strengthening family resilience. New York: Guilford Press.

Wolfson, A., Lacks, P., & Futterman, A. (1992) Effects of parent training on infant sleeping patterns, parents' stress, and perceived parental competence. Journal of Consulting and Clinical Psychology, 60, 41-48.

LYNN LOUTZENHISER AND PHILLIP R. SEVIGNY

University of Regina

Lynn Loutzenhiser and Phillip Sevigny, Department of Psychology, University of Regina.

The authors wish to acknowledge this project was funded by the University of Regina, SSHRC/President's Fund.

Correspondence concerning this article should be addressed to Lynn Loutzenhiser, Department of Psychology, University of Regina, Regina, SK, Canada S4S 0A2. Electronic mail: [e-mail]

Table 1

Means and Standard Deviations for the Research Variables

                               Mothers        Fathers
                                M (SD)         M (SD)

Depression                     8.0 (5.0) *     5.4 (4.5) *
Parenting stress              38.8 (10.8)     36.6 (9.7)
Infant negativity             19.3 (5.2)      19.9 (4.7)
Marital satisfaction         119.5 (11.2)    118.3 (11.9)
Overall family functioning    1.50 (.36) *    1.60 (.39) *

* p < .05.

Table 2

Correlations between Infant Sleep Duration and Parent Variables

                                      1.        2.        3.

 1. Sleep duration
 2. Father's stress                 -.34 **
 3. Father's depression             -.09       .15
 4. Father's infant negativity      -.37 **    .41 **    .14
 5. Father's marital satisfaction    .12      -.34 **   -.40 **
 6. Father's family functioning     -.24 *     .36 **    .37 **
 7. Mother's stress                 -.01       .44 **    .20
 8. Mother's depression             -.03       .16       .46 **
 9. Mother's infant negativity      -.24 *     .28 *     .25 *
10. Mother's marital satisfaction   -.03      -.32 **   -.34 **
11. Mother's family functioning     -.09       .48 **    .24 *

                                      4.        5.        6.

 1. Sleep duration
 2. Father's stress
 3. Father's depression
 4. Father's infant negativity
 5. Father's marital satisfaction   -.35 **
 6. Father's family functioning      .39 **   -.73 **
 7. Mother's stress                  .39 **   -.31 **    .33 **
 8. Mother's depression              .29 *    -.45 **    .35 **
 9. Mother's infant negativity       .64 **   -.39 **    .48 **
10. Mother's marital satisfaction   -.27 *     .77 **   -.55 **
11. Mother's family functioning      .34 **   -.58 **    .55 **

                                      7.        8.        9.

 1. Sleep duration
 2. Father's stress
 3. Father's depression
 4. Father's infant negativity
 5. Father's marital satisfaction
 6. Father's family functioning
 7. Mother's stress
 8. Mother's depression              .44 **
 9. Mother's infant negativity       .42 **    .25 *
10. Mother's marital satisfaction   -.31 **   -.50 **   -.41 **
11. Mother's family functioning      .43 **    .53 **    .41 **

                                      10.

 1. Sleep duration
 2. Father's stress
 3. Father's depression
 4. Father's infant negativity
 5. Father's marital satisfaction
 6. Father's family functioning
 7. Mother's stress
 8. Mother's depression
 9. Mother's infant negativity
10. Mother's marital satisfaction
11. Mother's family functioning     -.72 **

* p <.05. ** p <.01.

Table 3

Bivariate Correlations between Variables Used in Regression Analyses

                                   1.        2.        3.        4.

 1. Sleep duration
 2. Father's age                 -.15
 3. Father's education           -.09       .21
 4. Father's infant negativity   -.37 **   -.16       .04
 5. Father's PFI                 -.33 **   -.17       .00       .40 **
 6. Father's RFI                  .21       .08       .05      -.40 **
 7. Mother's age                 -.15       .82 **    .24 *    -.17
 8. Mother's education           -.20       .26 **    .50 **    .13
 9. Mother's infant negativity   -.24 *    -.16      -.03       .64 **
10. Mother's PFI                 -.01      -.23      -.14       .41 **
11. Mother's RFI                  .05       .06       .04      -.34 **

                                   5.        6.        7.        8.

 1. Sleep duration
 2. Father's age
 3. Father's education
 4. Father's infant negativity
 5. Father's PFI
 6. Father's RFI                 -.49 **
 7. Mother's age                 -.15       .08
 8. Mother's education           -.16       .03       .42 **
 9. Mother's infant negativity    .36 **   -.48 **   -.15       .07
10. Mother's PFI                  .48 **   -.42 **   -.31 **   -.12
11. Mother's RFI                 -.50 **    .66 **    .12       .03

                                   9.        10.

 1. Sleep duration
 2. Father's age
 3. Father's education
 4. Father's infant negativity
 5. Father's PFI
 6. Father's RFI
 7. Mother's age
 8. Mother's education
 9. Mother's infant negativity
10. Mother's PFI                  .43 **
11. Mother's RFI                 -.44 **   -.53 **

* p < .05. ** p < .01.

Table 4

Multiple Regression Analyses Assessing the Relationship between
Parents' Psychological Functioning and Infant Sleep Duration

                                         Fathers

Step / Variable         B     SE B   [beta]    [R.sup.2]     F for
                                               increase     [DELTA]
                                                           [R.sup.2]

Step 1                                            .03       1.02
  Age                 -.033   .02    -.18
  Education level      .029   .13     .03

Step 2                                            .22      17.70 ***
  Opposite sex PFI      .42   .10     .47 ***

Step 3                                            .05       4.43 *
  Infant negativity    .061   .03     .25 *

Step 4                                            .07       7.03 *
  Infant sleep         -.16   .06    -.31 *

                                         Mothers

Step / Variable         B     SE B   [beta]    [R.sup.2]     F for
                                               increase     [DELTA]
                                                           [R.sup.2]

Step 1                                            .09       3.33 *
  Age                 -.075   .03    -.31
  Education level      .017   .17     .01

Step 2                                            .20      17.54 ***
  Opposite sex PFI      .51   .12     .45 ***

Step 3                                            .06       5.97 *
  Infant negativity    .068   .03     .27 *

Step 4                                            .02       2.01
  Infant sleep         .095   .07     .16

Note. For both mothers and fathers, final [R.sup.2] = .37;
final adjusted [R.sup.] = .32

* p < .05. ** p < .01. *** p < .001.

Table 5

Multiple Regression Analysis Assessing the Relationship between
Parents Relational Functioning and Infant Sleep Duration

                                         Fathers

                        B     SE B   [beta]    [R.sup.2]     F for
                                               increase     [DELTA]
                                                           [R.sup.2]

Step / Variable

Step 1                                            .01        .26
  Age                  .018   .03     .08
  Education level      .025   .16     .02

Step 2                                            .42      49.21 ***
  Opposite sex RFI      .65   .09     .65 ***

Step 3                                            .03       4.33 *
  Infant negativity    -.06   .03    -.20 *

Step 4                                            .01       1.76
  Infant sleep         .082   .06     .13

                                         Mothers

                         B    SE B   [beta]    [R.sup.2]     F for
                                               increase     [DELTA]
                                                           [R.sup.2]

Step / Variable

Step 1                                            .02        .51
  Age                  .034   .03     .13
  Education level     -.030   .18    -.02

Step 2                                            .42      51.72 ***
  Opposite sex RFI      .65   .09     .65 ***

Step 3                                            .02       2.01
  Infant negativity    -.04   .03    -.15

Step 4                                            .01       1.32
  Infant sleep        -.068   .06    -.11

Note. For fathers, final [R.sup.2] = .47 and final adjusted
[R.sup.2] = .44; for mothers, [R.sup.2] = .47 and final adjusted
[R.sup.2] = .43

* p < .05. ** p < .01. *** p < .001.