The sleep hygiene intervention evaluated in this study provided little benefit to mothers or their partners from socioeconomically advantaged backgrounds, but provided some benefit to younger new mothers with fewer resources. As such, the study findings partially support the first hypothesis, and the answer to the question of whether modifications to the bedroom environment can improve the sleep of new parents seems to be “maybe a little.” However, the relatively weak findings of this study compared to the stronger findings of prior studies focused on infant sleep interventions (Hall et al., 2006
; Stremler et al., 2006
) suggest that bedroom modifications based on sleep hygiene principles are insufficient on their own, and would be more effective in fostering parent sleep if supplemented by specific strategies for promoting infant sleep. These infant strategies might include those that facilitate infant self-soothing behaviors and circadian entrainment and avoid negative sleep associations (Mindell et al., 2009
; Sadeh, Mindell, Luedtke,&Wiegand, 2009
; Stremler et al., 2006
The second hypothesis regarding the acceptability of the intervention components also was partially supported. The nightlight was highly acceptable to new parents, the bedside bassinet was acceptable in the first month with a slight decrease by the third month, and the sound machine did not meet the acceptability threshold hypothesized in this study. Further research is needed to identify ways in which the sound machine could be more appealing for parents to consider as a way to mask environmental noises. Identifying which types of parents or environments are most in need of masking noise to minimize arousals from sleep would also be an area for further research consideration.
One of the challenges of this study was that the intervention components were widely available and seemed to be gaining in popularity, thereby making it difficult to find an adequate control group of parents not using some or all three components of the sleep hygiene intervention. Spontaneous use of the intervention components was of particular concern in Sample 1, which may help to explain the lack of group differences in this sample of socially and economically advantaged women. Sample 1 was recruited exclusively from childbirth classes, and it is possible that the class included information for promoting sleep that increased spontaneous use of the intervention strategies. Spontaneous use of the intervention components was not systematically assessed in the Sample 2 control group, but given their more limited educational, social, and material resources, it is less likely that they would adopt healthy sleep hygiene practices on their own. A greater difference in the use of the sleep hygiene strategies between the intervention and control group in Sample 2 would have resulted in more power to detect group differences in this sample. Furthermore, the home environments of participants in Sample 2 may have been less conducive to good sleep, thereby enhancing the usefulness of the sleep hygiene techniques. For instance, a white noise machine may be more beneficial for women living in larger households and in more crowded conditions.
In addition to spontaneous use of the intervention components in the control group of this study, there was also low fidelity in the intervention group, thereby limiting the ability to detect group differences. Parents were often struggling with the demands of newborn care, and if an intervention strategy was not immediately helpful, they were sometimes quick to abandon it and try something else. As a result, parents frequently reported using multiple strategies for managing sleep, and it was often unclear which approaches were most helpful.
With any behavioral intervention, there is the possibility of spontaneous use and individual customization of the intervention components. Therefore, it is essential to assess intervention use in both control and intervention groups. This can be challenging when trying to avoid contamination because asking about use could inadvertently suggest the intervention components to those in the control group. To avoid introducing the intervention to the control group, assessment should only be done at the conclusion of the study. However, recall bias, particularly in longer studies, can be a threat to validity. These challenges highlight the importance of conducting intention-to-treat analysis, which takes into consideration spontaneous use in the control group, as well as adaptation and non-use of the components in the intervention group.
Because the intervention components were administered as a package, the benefit of individual components could not be determined by this study. For example, infant proximity without a countermeasure, like white noise, to mask the infant’s noisy sleep could unnecessarily awaken a highly vigilant new mother. However, the practice of maintaining infant proximity was a popular night-time care strategy in both the intervention and control groups of this study. Although some parents reported concerns that their infant would have difficulty later transitioning to his or her own room, the vast majority clearly understood the advantages of infant proximity during the first few postpartum months. Parent–infant bed-sharing was surprisingly common across both samples, and the rates were markedly higher than the 12% reported nationally (Willinger et al., 2003
). These findings may reflect regional differences in bed-sharing popularity or provide additional evidence that the practice of bed-sharing is becoming more common across all socioeconomic groups.
Noise attenuation was not an issue many parents considered, although reactions to the white noise machine were mixed. Some parents found it very effective, particularly for the infant; others reported that the background noise disturbed their own sleep or the sleep of the other adult bed partner. It was unclear whether this was due to inadequate adaptation to the white noise or if no amount of adaptation would have helped. Dim lighting was the most popular component of the intervention, and yet, some parents felt additional light was necessary to properly conduct infant care.
There are other sleep hygiene principles that were not included as part of this intervention, but might be considered in future studies. Exposure to daylight, in particular, plays an important role in circadian entrainment and the regulation of sleep–wake patterns for infants and adults (Czeisler & Gooley, 2007
; Harrison, 2004
), and increasing daytime exposure to sunlight might have beneficial effects on the sleep of parents and their infant (Tsai, Barnard, Lentz, & Thomas, 2009
Obtaining stable measures of sleep patterns among new parents can be challenging. In this study, both objective and subjective measures of parental sleep were used. To minimize the burden on participants, reduce potential for missing data, and maximize compliance with monitoring, a 48-hour monitoring period was used rather than other recommended time frames (Morgenthaler et al., 2007
). Given weekend versus weekday variability, the focus was limited to weekday sleep patterns. Postpartum sleep can be highly variable and can change significantly over a relatively short period of time. Therefore, future researchers should address appropriate time frames for monitoring sleep in this specific clinical population.
In conclusion, the results of this study suggest that simple bedroom modifications based on sleep hygiene principles have different beneficial outcomes depending on the family’s socioeconomic resources. Some parents reported that the bedside bassinet was the perfect solution; others reported that their sleep and well-being improved immensely once they began bed-sharing or once their infant was moved to a separate room. There was similar diversity in the responses to the white noise machine and the dim lighting.
In light of these findings, the most helpful intervention may be to provide new parents with accurate information regarding sleep during the postpartum period. Before the birth occurs, new parents should have information about principles for promoting both parental and infant sleep. Nurses can acknowledge a variety of suitable parenting practice strategies as part of the educational session, giving parents the opportunity to think through and discuss which strategies might work best in light of their personal preferences and family circumstances. Such an approach is likely to promote parent competence while also improving sleep and reducing the stress of new parenthood.