Sleep Consolidation, Sleep Problems, and Co-Sleeping: Rethinking Normal Infant Sleep as Species-Typical

Sleep characteristics and changes in sleep patterns among infants in Bhaktapur, Nepal

OBJECTIVE

Sleep undergoes major changes during the first year of life, but the characteristics of sleep among infants in low and middle-income countries are not well documented. This study describes sleep characteristics and changes in sleep patterns in infants at 6 and 12months of age from Bhaktapur, Nepal.

METHODS

This was a community-based longitudinal study comprising 735 infants. Sleep characteristics were obtained by interview with the mother using the Brief Infant Sleep Questionnaires. The stability of sleep duration and night awakenings were estimated by logistic regression analysis.

RESULTS

Cosleeping in the parent's bed at 6 and 12months of age was almost universal (>97%). At 6months of age, 254 (35%) and at 12months of age, 341 (46%) infants had a total 24-hour sleep duration <12 hours. Night awakenings >3 times per night were common (65%) both at 6 and 12months of age. Infants with frequent nightly awakenings at 6months had increased odds of frequent nightly awakenings at 12months (OR=2.2; 95% CI: 1.6, 2.9). Very few (<3%) mothers reported sleep problems in their infants at 6 and 12months of age.

CONCLUSIONS

Cosleeping was almost universal among Nepalese infants, and very few of the mothers reported sleep problems in their infants. Infants at 6 and 12months had similar patterns for both sleep duration and nocturnal awakenings. For infants, there were increased odds of having similar sleep duration and nocturnal awakening at 6 and 12months.

Infant Care: Predictors of Outdoor Walking, Infant Carrying and Infant Outdoor Sleeping

BACKGROUND

Although spending time outdoors is beneficial for development, little is known about outdoor time during infancy. The aim of this study was to assess frequencies and durations of (1a) outdoor walking and carrying in mother-infant dyads and (1b) infant outdoor sleeping in a stationary cot or pram. We furthermore aimed to identify associations of (2a) outdoor walking and carrying and (2b) infant outdoor sleeping, with infant, maternal and environmental sample characteristics.

METHODS

An online survey was distributed among mothers of 0- to 12-month-old infants. Initially, 1453 mothers were recruited, of which 1275 were included in the analyses. With respect to (1a) the outcomes of interest were: mother-infant dyads' total weekly duration of walking in minutes, frequency of walking on weekdays, as well as weekends, and the frequency of using an infant carrier during walks, as well as the daily duration of carrying in hours (indoors and outdoors together). With respect to (1b) the outcome variables were: placing the infant outdoors to sleep (yes/no), the total weekly duration of outdoor sleeping and the weekly frequency of outdoor sleeping. For aim 2, associations of the outcome variables with infant (i.e., age), maternal (i.e., working status) and environmental (i.e., house type) sample characteristics were assessed.

RESULTS

Mother-infant dyads engaged in walks for a total weekly duration of 201 min, for approximately one to three walks over weekdays (Monday through Friday), as well as one to three walks on the weekend. The infant carrier was used by 22% of mothers at least half of the time during outdoor walks, and 18% reported a daily duration of infant carrying of one hour or more. Among other associations, infant and maternal enjoyment of outdoor walking correlated positively with the duration as well as the frequency of walking during weekdays and during the weekend. Furthermore, employed mothers walked for a shorter duration and less frequently on weekdays as compared to mothers on maternity leave or mothers without a paid job. The availability of nearby recreational areas correlated positively with the weekly duration and frequency of walks. The infant carrier was used more frequently during outdoor walks if more than one child lived in the household. Infant carrying during outdoor walks was also related to infant behavior at night. Roughly a third of the mothers (29%) regularly had their infant sleep outdoors for a weekly duration of four hours and a weekly frequency of approximately one to two times. Younger infants, infants of mothers with higher education and infants living in detached houses were more likely to be placed outdoors to sleep.

DISCUSSION

We identified associations of infant, maternal and environmental characteristics with outdoor time spent during infancy. These results lay the foundation for future research on the effects of the outdoors on child development as well as on facilitators and barriers for caregivers.

Construction of the Views oN Infant Sleep (VNIS) Questionnaire

Parents' beliefs about infant sleep behaviour vary over time and across cultures. No validated instrument exists to understand parents' pre- and postnatal views on infant sleep behaviours, which may influence their caregiving decisions. The Views oN Infant Sleep Questionnaire (VNIS) will be a tool to assess parents' beliefs in order to facilitate tailored perinatal care, increase the reliability of postnatal self-report measures, allow for cross-cultural comparisons, and provide a baseline for researchers to use in longitudinal studies. We recruited an online sample of 971 female participants who were resident in the United Kingdom, at least 28 weeks pregnant, and at least 18 years of age. The initial questionnaire consisted of 31 questions about infant independence, night-waking, infant feeding, touch, and safety, and items were rated on a 5-point Likert scale. The item pool was reduced to 12 using principal component analysis and a structure was found for the three components "Closeness", "Independence", and "Night-waking". Overall, these results suggest that the VNIS can provide a brief scale to measure different aspects of individuals' beliefs about infant sleep. In further research the VNIS needs to be validated with a confirmatory factor analysis in another sample, and to be tested as a cross-cultural instrument.

Using complexity science to understand the role of co-sleeping (bedsharing) in mother-infant co-regulatory processes

Human infants spend most of their time sleeping, but over the first few years of life their sleep becomes regulated to coincide more closely with adult sleep (Galland et al., 2012; Paavonen et al., 2020). Evidence shows that co-sleeping played a role in the evolution of infant sleep regulation, as it is part of an ancient behavioral complex representing the biopsychosocial microenvironment in which human infants co-evolved with their mothers through millions of years of human history (Ball, 2003; McKenna 1986, 1990). This paper is a conceptual, interdisciplinary, integration of the literature on mother-infant co-sleeping and other mother-infant co-regulatory processes from an evolutionary (biological) perspective, using complexity science. Viewing the mother-infant dyad as a "complex adaptive system" (CAS) shows how the CAS fits assumptions of regulatory processes and reveals the role of the CAS in the ontogeny of mother-infant co-regulation of physiological (thermoregulation, breathing, circadian rhythm coordination, nighttime synchrony, and heart rate variability) and socioemotional (attachment and cortisol activity) development.

Sleep problems and infant motor and cognitive development across the first two years of life: The Beijing Longitudinal Study

The present study examined bidirectional effects between sleep problems (nocturnal awakenings and insufficient nocturnal sleep) and infant development (gross motor, fine motor, and cognition) in a sample of 182 infants (89 girls) and their parents living in Beijing (China). Using 3 waves of longitudinal data (at 6 months, 1 year, and 2 years of age), this study (a) explored the differences in sleep patterns and developmental outcomes between infants in the current sample and infants from other cultures; and primarily examined (b) whether nocturnal awakenings and insufficient nocturnal sleep prospectively predicted infant development; (c) or whether infant development predicted sleep problems. Mothers reported their children's sleep problems, and infant development was assessed with Bayley III. Sleep patterns of Beijing infants were slightly different from those from Finland and Singapore, and most scores on Bayley III in this Beijing sample were higher than those in Danish, Dutch and Sri Lankan samples. Sleep problems and developmental measures were stable across the 3 times of assessments, but cross-lagged associations were limited in number and strength. High scores on the Bayley at 6 months predicted less nocturnal awakenings at 1 year of age. Insufficient nocturnal sleep at 1 year predicted poor fine motor development at 2 years. Thus, findings suggest some bidirectional associations between infant development and sleep problems and further highlight the need to understand these relations within specific cultural contexts.

Reasons mothers bedshare: A review of its effects on infant behavior and development

Bedsharing is controversial for nighttime caregiving in the U.S. today, as in most of the West. However, from the standpoint of evolutionary pediatrics, anthropology, and cultural psychology, bedsharing is not controversial at all, representing the context for human infant evolution and conferring a host of physiological benefits to the infant as well as the mother. In an effort to understand the rise in Western bedsharing in recent decades (and following Ball, 2002; McKenna & Volpe, 2007), Salm Ward (2015) systematically reviewed the literature on mother-infant bedsharing and identified ten reasons why mothers choose to bedshare: (1) breastfeeding, (2) comforting for mother or infant, (3) better/more sleep for infant or parent, (4) monitoring, (5) bonding/ attachment, (6) environmental reasons, (7) crying, (8) cultural or familial traditions, (9) disagree with danger, and (10) maternal instinct. The current paper offers the "review behind the review," highlighting the scientific evidence behind the reasons mothers give for their decision to bedshare, focusing on how mothers' decisions about infant sleep location influence infant behavior and development.