Infant sleep-wake behaviors at two weeks, three and six months

Maturation of infant sleep during the first 6 months of life: a mini-scoping review

Introduction

Several foundational aspects of neurodevelopment occur during the early months of infant life, most notably the maturation and consolidation of wake/sleep cycles. Past studies have had difficulty quantifying infant sleep, with most researchers relying on low-resolution caregiver surveys. Data obtained from nightly measurements have not yet been aggregated across studies to clarify developmental trajectories and population norms. This mini-scoping review assesses data collected from actigraphy and sleep diaries; the two most common nightly infant sleep measurement techniques.

Methods

The PubMed database was used to identify studies from 2000 to 2024 utilizing actigraphy and/or sleep diaries, and which report total night sleep (TNS), longest sleep stretch (LSS), and/or frequency of night wakings (NW) during the first 6 months of life. Data was then compiled per metric to reveal the extent of inter-and intra-study variability, and curves were fit to highlight developmental trajectories.

Results

A total of 35 articles met inclusion criteria (16 studies using actigraphy only, 8 studies using sleep diary only, and 11 studies using both actigraphy and sleep diaries). The sample sizes of these studies ranged from 13 to 320 infants. The majority of studies (N = 28) reported two or fewer age data points.

Conclusion

Aggregation and regression revealed longitudinal trends, but highlighted variability within and between studies, as well as systematic differences between measurement methods. In order to establish reliable benchmarks, future studies must include well defined, objective measures of sleep as well as greater methodological consistency, larger cohorts, more frequent sampling, and clear disclosure of methodological limitations.

Sleep as a driver of pre- and postnatal brain development

In 1966, Howard Roffwarg proposed the ontogenic sleep hypothesis, relating neural plasticity and development to rapid eye movement (REM) sleep, a hypothesis that current fetal and neonatal sleep research is still exploring. Recently, technological advances have enabled researchers to automatically quantify neonatal sleep architecture, which has caused a resurgence of research in this field as attempts are made to further elucidate the important role of sleep in pre- and postnatal brain development. This article will review our current understanding of the role of sleep as a driver of brain development and identify possible areas for future research. IMPACT: The evidence to date suggests that Roffwarg's ontogenesis hypothesis of sleep and brain development is correct. A better understanding of the relationship between sleep and the development of functional connectivity is needed. Reliable, non-invasive tools to assess sleep in the NICU and at home need to be tested in a real-world environment and the best way to promote healthy sleep needs to be understood before clinical trials promoting and optimizing sleep quality in neonates could be undertaken.

Infants' early recovery from sleep disturbance is associated with a lower risk of developmental delay in the Japan Environment and Children's Study

To examine whether patterns, such as the timings of onset or recovery from sleep disturbance, are associated with later developmental problems, including autism spectrum disorder (ASD). Mothers participating in the Japan Environment and Children's Study with a child aged 3 years were included in the analyses. Children were assessed for short sleep and frequent awakenings at 1 month, 6 months, and 1 year of age. Developmental problems were evaluated at 3 years of age based on ASD diagnosis and developmental delay, using the Japanese translation of the Ages and Stages Questionnaire (ASQ) 3rd edition. Sleep disturbance patterns were classified by onset age, and developmental problem risks were examined based on onset/recovery ages. Among 63,418 mother-infant dyads, 0.4% of infants were later diagnosed with ASD, and 14.4% had abnormal scores on any ASQ domains. The later the onset of short sleep, the lower the risk of abnormal ASQ scores (RR of short sleep onset at 1 year: 1.41; 6 months: 1.52; 1 month: 1.57). The earlier the infants recovered from short sleep persistence, the lower the risk of developmental delay (RR of remittance of sleep problems identified at 1 month by 6 months: 1.07; 1 year: 1.31; not before 1 year: 1.57). Although not all patterns were significant, later short sleep onset and earlier recovery were associated with lower ASD risk. These findings may have significant implications for future interventions in infant development.

Sleep duration trajectories and cognition in early childhood: A systematic review

Sleep is dynamic in childhood and studies have shown the relationship between sleep and cognition in children. As the human brain is the most plastic during childhood, the study of longitudinal sleep patterns and neurocognition is an important research area. We aimed to systematically review studies that investigated sleep duration trajectories and cognition in typically-developing children. We searched four databases for articles published between 2003 to October 2023. We included observation studies of children with sleep duration trajectories as a predictor and outcomes related to cognition, memory, language, developmental milestones, intelligence or executive function. We excluded studies where children had atypical development or completed the sleep and neurocognitive assessments after six and 12 years of age respectively. Out of 752 articles identified, 511 were screened and 23 full texts were assessed. The selected studies included three single trajectory and four multiple group trajectories studies. We found associations between both types of trajectories and cognitive development. Overall, children with longer sleep trajectories or more mature sleep pattern with rapid decrease in sleep duration, had better performance scores in developmental assessment tools, and intelligence tests. Findings for language and executive functioning were mixed, whereby some studies found associations and others did not.

Sleep characteristics, early spontaneous movements, and developmental functioning in preterm infants in the early postnatal period

OBJECTIVE

This study aimed to investigate the following: (i) sleep characteristics in preterm infants at 9-20 weeks of corrected age, and (ii) differences in early spontaneous movements and developmental functioning results between the groups based on some sleep characteristics.

METHODS

Seventy-four preterm infants (36 female) were included. Sleep characteristics were assessed according to the Brief Infant Sleep Questionnaire (BISQ). The infants were divided into two groups based on total sleep duration: less than 12 h (38 infants), and 12 h and more (36 infants). Video recordings were made for the General Movements Assessment (GMA) and evaluated using the Motor Optimality Score for 3- to 5-Month-Old-Infants-Revised (MOS). Cognitive, language, and motor development were assessed using the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III).

RESULTS

The total sleep duration of all preterm infants (mean ± SD) was 11.8 ± 3.3 h. Infants who had absent fidgety movements slept less than 12 h, and fidgety movements differed between the groups (p = 0.012). Infants who slept 12 h or more had significantly higher MOS (p = 0.041), cognitive (p = 0.002), language (p < 0.001), and motor (p = 0.002) development results. Infants who snored had lower MOS (p = 0.001), cognitive (p = 0.004), language (p = 0.002), and motor (p = 0.001) development results. Infants with fewer than three nocturnal awakenings had significantly higher Bayley-III cognitive (p = 0.007), language (p = 0.032), and motor (p = 0.005) domain results. Prone and supine sleeping positions showed higher motor domain results than lateral positions (p = 0.001).

CONCLUSIONS

Sleep in preterm infants might be a key factor in early developmental functioning processes and nervous system integrity. Even in the first months of life, there are substantial differences in cognitive, language, and motor development in association with sleep characteristics.

Contributions of the light environment and co-sleeping to sleep consolidation into nighttime in early infants: A pilot study

BACKGROUND

Sleep consolidation into nighttime is considered the primary goal of sleep development in early infants. However, factors contributing to sleep consolidation into nighttime remain unclear.

AIM

To clarify the influences of the light environment and nighttime co-sleeping on sleep consolidation into nighttime in early infants.

STUDY DESIGN

Cross-sectional study.

SUBJECTS AND METHODS

Sleep-wake time and light stimulation were measured in infants for 4 consecutive days using actigraphy. The infants' mothers were asked to complete a sleep events diary and a questionnaire about childcare, including "co-sleeping", defined as when the infant and mother slept on the same surface throughout the night.

OUTCOME MEASURES

The data were analyzed with a focus on daytime and nighttime sleep parameters.

RESULTS

Daytime light stimulation reduced daytime "active sleep", tended to reduce daytime sleep, and increased daytime waking. Nighttime light stimulation reduced nighttime "quiet sleep" and nighttime sleep and increased nighttime waking. Co-sleeping reduced nighttime waking, and, as a result, nighttime sleep time and sleep efficiency increased. Co-sleeping reduced daytime sleep and tended to increase daytime waking. Consequently, co-sleeping tended to increase the ratio of nighttime sleep to daytime sleep.

CONCLUSIONS

The present findings suggest that an appropriate light environment promotes daytime waking and nighttime sleep in early infants, but it does not contribute to sleep consolidation into nighttime by itself. On the other hand, co-sleeping may promote sleep consolidation into nighttime. Therefore, further methods for safe co-sleeping need to be established while avoiding risk factors for sudden unexpected death in infancy/sudden infant death syndrome.

Maternal Prenatal Depressive Symptoms and Infant Sleep Problems: The Role of Infant Temperament and Sex

OBJECTIVES

We aimed to analyze whether (1) infant temperament mediates the impact of maternal prenatal depressive symptoms on infant sleep problems and (2) the mediation role of infant temperament was moderated by the infant's sex.

METHODS

The sample was comprised of 172 mother-infant dyads. Mothers completed self-reported measures of prenatal and postnatal depressive symptoms, infant temperament (negative affectivity, surgency/extraversion, and orienting regulation), and sleep problems.

RESULTS

While controlling for maternal postnatal depressive symptoms, our results revealed that (1) infant negative affectivity at two weeks partially mediated the impact of maternal prenatal depressive symptoms on sleep anxiety at six months, and (2) this mediation is independent of the infant's sex.

CONCLUSIONS

Our findings provided evidence that negative affectivity can be an early specific marker of sleep anxiety and can partially explain the negative impact of maternal prenatal depressive symptoms on further sleep problems in the infant.

Possible contribution of better maternal psychological well-being to the acquisition of sleeping through the night in infants during the early postpartum period

The objective of this study was to elucidate whether better maternal psychological well-being contributes to the acquisition of "sleeping through the night" (STN) in infants during the early postpartum period. Fifty-two primiparous mothers completed the General Health Questionnaire-28 (GHQ-28) in the third trimester (prenatal) and when the conceptional ages of their babies reached 8-9 weeks (hereafter, 2 months), 12-13 weeks (3 months), and 16-17 weeks (4 months). They also recorded babies' nocturnal sleep patterns in a timetable for 5 consecutive days each month postpartum. "Regular STN" was defined when the mean of longest nocturnal sleep duration for 5 consecutive days was > 8 h or between 6 and 8 h with < 1.0 nocturnal awakenings. According to these criteria, a total of 14 infants (27 %) acquired regular STN at 4 months (referred to as "STN infants"), with STN infants showing a marked increase in longest nocturnal sleep duration and a decrease in nocturnal awakenings from 2 to 3 months of age. The mothers of STN infants demonstrated steady reductions in postnatal GHQ-28 scores and had significantly lower prenatal GHQ-28 scores compared with the mothers of non-STN infants (3.7 ± 3.0 vs. 6.4 ± 4.1, p = 0.027). In random forest models for binomial classification, both prenatal and postnatal (at 4 months) GHQ-28 scores were identified as significant covariates for distinguishing STN infants, and other important covariates, including weeks of delivery, stepfamily, birth weight of the infant, and maternal co-sleeping at bedtime, were selected. Among these covariates, maternal co-sleeping at bedtime had relatively stronger correlations with both STN infants (r = - 0.440) and prenatal maternal GHQ-28 scores (r = 0.377). In conclusion, because prenatal maternal psychological well-being was thought to predict the acquisition of STN in infants, infants born from mothers with better psychological well-being appear to have some advantages in acquiring STN. These cross-lagged correlations suggest that the pathway from mothers to infants may be mediated by certain parenting behaviors, such as maternal co-sleeping at bedtime.

Sleep quality and temperament in association with autism spectrum disorder among infants in Japan

BACKGROUND

Sleep problems and irritable temperaments are common among infants with autism spectrum disorder (ASD). The prospective association between such sleep problems and irritable temperaments and ASDs needs to be determined for elucidating the mechanism and exploring the future intervention study. Thus, in this study, we investigated whether sleep quality and temperament in 1-month-old infants are associated with the onset of ASD in 3-year-old children. We also assessed its sex-stratified associations.

METHODS

We conducted a longitudinal study using data from 69,751 mothers and infants from a large-cohort study, the Japan Environment and Children's Study. We examined the prospective association between infant sleep quality and temperament at 1 month of age and ASD diagnosis by 3 years of age.

RESULTS

Here we show infants with longer daytime sleep have a higher risk of later ASD than those with shorter daytime sleep (risk ratio [RR]: 1.33, 95% confidence interval [CI]: 1.01-1.75). Infants who experienced intense crying have a higher risk of ASD than those who did not (RR: 1.31, 95% CI: 1.00-1.72). There is a difference in sex in the association between a bad mood and later ASD. In particular, female infants experiencing bad moods have a higher risk of ASD than others (RR: 3.59, 95% CI: 1.91-6.75).

CONCLUSIONS

The study findings provide important information for future intervention to reduce the risk of future ASD.

Sensory processing and sleep characteristics in preterm infants in the early period of life

OBJECTIVE

The present study aimed to investigate the following: (i) differences in sensory processing and sleep characteristics between preterm infants born at < 32 weeks', vs. those born at ≥ 32 weeks' gestation; (ii) differences in sleep characteristics between preterm infants with typical vs. atypical sensory processing; and (iii) relationship between sensory processing and sleep characteristics in preterm infants at 3 months of age.

METHODS

A total of 189 preterm infants, 54 born at < 32 weeks' gestation (26 females; mean gestational age [standard deviation (SD)], 30.1 [1.7] weeks), and 135 born at ≥ 32 weeks' gestation (78 females; mean gestational age [SD], 34.9 [0.9] weeks) were included in the present study. Sleep characteristics were evaluated using the Brief Infant Sleep Questionnaire, and sensory processing was assessed using the Infant Sensory Profile-2.

RESULTS

There were no significant differences in sensory processing (P > 0.05) or sleep characteristics (P > 0.05) between the preterm groups; however, more infants snored in the <32 weeks' gestation group (P = 0.035). Preterm infants with atypical sensory processing showed lower nighttime (P = 0.027) and total sleep durations (P = 0.032), and higher rates of nocturnal wakefulness (P = 0.038) and snoring (P = 0.001) than preterm infants with typical sensory processing. A significant relationship, therefore, was observed between sensory processing and sleep characteristics (P < 0.05).

CONCLUSIONS

Sensory processing patterns may play an important role in understanding sleep problems in preterm infants. The early detection of sleep problems and sensory processing difficulties are necessary for early intervention.

Sleep assessment in preterm infants: Use of actigraphy and aEEG

OBJECTIVE

Objective methods to monitor the sleep of preterm infants at the neonatal intensive care unit (NICU) are required to prevent potentially adverse neurodevelopmental outcomes. This study aimed to determine the concordance of actigraphy and amplitude-integrated electroencephalogram (aEEG) against gold standard direct observation (DO) in assessing sleep/wake states of typically developing preterm infants.

METHODS

This prospective observational study was conducted in a single center level III NICU. Sleep variables were measured using Philips Respironics Mini-Mitter® Actiwatch-2 for 24 h and compared with 8-h matched data of aEEG and DO. Sensitivity-specificity analysis, Cohen's kappa, prevalence-adjusted and bias-adjusted kappa (PABAK), and Bland Altman plots were generated.

RESULTS

Seventeen preterm infants were recruited. A total of 11252 epochs were studied. Sensitivity (86.4%), agreement rate (67.9%), and predictive value for wake (47.9%) for the actigraphy were highest at the automatic activity threshold whereas specificity (54.5%) and predictive value for sleep (75.5%) were highest at low threshold. The sensitivity of aEEG was 79.3% and the specificity was 54.3%. At all thresholds, the agreement was largely equivalent with low kappas (0.14-0.17) and PABAK coefficients (0.22-0.35) for actigraphy and DO. Moderate agreement was observed between aEEG and DO according to the PABAK coefficient (0.44). Mean differences in sleep parameters were not different between DO and aEEG as well as DO/aEEG and actigraphy at medium threshold (p > 0.05).

CONCLUSIONS

Actigraphy at medium threshold can be used in depicting sleep in typically developing preterm infants at NICU. aEEG may be an alternative adjunctive method to actigraphy for the evaluation of sleep/wake states in the NICU setting.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04145362.

The Architecture of Early Childhood Sleep Over the First Two Years

INTRODUCTION

The architecture and function of sleep during infancy and early childhood has not been fully described in the scientific literature. The impact of early sleep disruption on cognitive and physical development is also under-studied. The aim of this review was to investigate early childhood sleep development over the first two years and its association with neurodevelopment.

METHODS

This review was conducted according to the 2009 PRISMA guidelines. Four databases (OVID Medline, Pubmed, CINAHL, and Web of Science) were searched according to predefined search terms.

RESULTS

Ninety-three studies with approximately 90,000 subjects from demographically diverse backgrounds were included in this review. Sleep is the predominant state at birth. There is an increase in NREM and a decrease in REM sleep during the first two years. Changes in sleep architecture occur in tandem with development. There are more studies exploring sleep and early infancy compared to mid and late infancy and early childhood.

DISCUSSION

Sleep is critical for memory, learning, and socio-emotional development. Future longitudinal studies in infants and young children should focus on sleep architecture at each month of life to establish the emergence of key characteristics, especially from 7-24 months of age, during periods of rapid neurodevelopmental progress.

Association of sleep quality with temperament among one-month-old infants in The Japan Environment and Children’s Study

This study aimed to examine the association between infant sleep quality and temperament in one-month-old infants using a large cohort study data. We used data from the Japan Environment and Children’s Study, a cohort study which follows around 100,000 women from pregnancy until their children’s development. The mothers were asked about their infants’ sleep and temperament using a structured questionnaire. Frequent crying (adjusted odds ratio [AOR]: 1.05, 95% confidence interval [CI]: 1.00–1.10) and intense crying (AOR: 1.19, 95% CI: 1.13–1.25) were positively associated with longer sleep periods during the day than at night. Female infants with longer daytime sleep periods than that at nighttime were more likely to cry frequently (AOR: 1.11, 95% CI: 1.04–1.20). Parous women with infants who had frequent night awakening believed their infants cried more intensely (AOR: 1.17, 95% CI: 1.03–1.31). The study demonstrated a specific association between sleep quality and temperament in one-month-old infants. Based on the results of this study, further sleep intervention studies are required to improve infant temperament.

A qualitative study of the sleep ecology of infants under 2 years old and their mothers in South Korea

OBJECTIVES/DESIGN

Infancy is a crucial period for establishing an individual's sleep pattern, and it is a common period during which infants and mothers experience sleep problems. The aim of this qualitative study was to explore the sleep ecology of infants under 2 years of age and their mothers.

SETTING/PARTICIPANTS

The study participants were 20 mothers with infants aged 3-19 months living in South Korea.

METHODS

Data were collected through in-depth interviews and analyzed using the thematic analysis.

RESULTS

Five themes related to the sleep of infants and their mothers emerged from the data: (1) changes in sleep patterns, (2) room-sharing, (3) environmental factors affecting sleep, (4) efforts to improve sleep quality, and (5) infant sleep and the mother's health. The sleep patterns of infants and their mothers were mutually interrelated, and were strongly affected by various environmental factors, including infants' biological maturity (a microsystem) as well as cultural factors (a macrosystem). Culture had an especially profound effect on sleep patterns of infants, similar to the effects of microsystem-level factors.

CONCLUSIONS

To improve the sleep quality of infants and mothers, an ecological approach considering the biological characteristics and cultural contexts of infants is required based on an understanding of sleep as a phenomenon that evolves in a relationship of mutual influence between infants and mothers.

Synchronizing Our Clocks as We Age: The Influence of the Brain-Gut-Immune Axis on the Sleep-Wake Cycle Across the Lifespan

The microbes that colonize the small and large intestines, known as the gut microbiome, play an integral role in optimal brain development and function. The gut microbiome is a vital component of the bi-directional communication pathway between the brain, immune system, and gut, also known as the brain-gut-immune axis. To date there has been minimal investigation into the implications of improper development of the gut microbiome and the brain-gut-immune axis on the sleep-wake cycle, particularly during sensitive periods of physical and neurological development, such as childhood, adolescence, and senescence. Therefore, this review will explore the current literature surrounding the overlapping developmental periods of the gut microbiome, brain, and immune system from birth through to senescence, while highlighting how the brain-gut-immune axis affects maturation and organisation of the sleep-wake cycle. We also examine how dysfunction to either the microbiome or the sleep-wake cycle negatively affects the bidirectional relationship between the brain and gut, and subsequently the overall health and functionality of this complex system. Additionally, this review integrates therapeutic studies to demonstrate when dietary manipulations, such as supplementation with probiotics and prebiotics, can modulate the gut microbiome to enhance health of the brain-gut-immune axis and optimize our sleep-wake cycle.

Parents matter: barriers and solutions when implementing behavioural sleep interventions for infant sleep problems

Behavioural sleep interventions (eg, extinction-based methods) are among the most efficacious evidence-based techniques in the treatment of infant sleep problems. However, behavioural sleep interventions can be challenging for families to successfully implement. This review aims to summarise current research surrounding the potential barriers that arise when clinicians attempt to implement extinction-based methods with parents of infants. We provide a model that summarises 3 types of contextual-barriers; socio-cultural barriers, parent barriers, and infant barriers. Based on the current evidence, we propose that adopting a stepped care approach, planning ahead, increasing support, motivational interviewing, and/or emotional regulation may serve as useful tools for parents when implementing extinction-based methods. By considering these techniques, more families may receive the benefits of improved infant sleep.

Unidirectional and bidirectional links between maternal depression symptoms and infant sleep problems

The present study explored (a) the unidirectional and bidirectional links between maternal depression symptoms and infant sleep problems and (b) the moderating role of the infant's sex on these unidirectional and bidirectional links. Mothers (N = 312) completed measures of depression symptoms at the third pregnancy trimester, and measures of depression symptoms and infant sleep problems at 2 weeks, and at 3 and 6 months postpartum. The findings revealed: (a) a main unidirectional link between maternal depression symptoms during the third trimester and infant sleep problems, particularly on infant unsettled sleep and daytime sleepiness at 3 and 6 months; (b) bidirectional links between maternal postpartum depression symptoms and infant unsettled sleep at 2 weeks, 3 and 6 months of life; and (c) the reported links between maternal depression symptoms and infant sleep problems occur specifically in boys and their mothers. Maternal prenatal depression symptoms are linked to infant sleep problems and infant sleep problems are linked to maternal postnatal depression symptoms. Boys are more susceptible to the effects of maternal prenatal and postnatal depression symptoms, and mothers of boys are more susceptible to the effects of boys' sleep problems.

Insomnia and poor sleep quality during peripartum: a family issue with potential long term consequences on mental health

BACKGROUND

Improving maternal's health is a worldwide priority. Sleep is a fundamental operating state of the central nervous system and it may be one of the most important psychophysiological processes for brain function and mental health. The study of maternal sleep problem including insomnia, however, implies deepening our understanding of family context. Family systems are dynamic and involve reciprocal interactions among members during day and night. So far, however, maternal and children's sleep has been rarely studied in a family perspective, and paternal sleep has often been neglected.

METHODS

The present work summarizes in a narrative review the state of the art of our current knowledge on the role of insomnia and poor quality of sleep for mental health in all family members in the peripartum period. The mother, the father, the child and the family interactive perspectives are considered.

RESULTS

Insomnia and poor sleep problems are frequent in all family members during peripartum. Poor sleep and insomnia symptoms are recognized as important risk factors for mental health in adults and children. Despite this alarming evidence, sleep is rarely assessed in clinical contexts.

CONCLUSIONS

Clinical implications include the utmost relevance of assessing sleep problems during pregnancy and early post-partum. Insomnia and poor sleep quality should be evaluated and treated in the clinical practice by using a "family perspective."

The Association between Diurnal Sleep Patterns and Emotions in Infants and Toddlers Attending Nursery

Background: Childcare programs often include mandatory naptime during the day. Loss of daytime sleep could lead to a moderate-to-large decrease in self-regulation, emotion processing, and learning in early childhood. Nevertheless, daytime sleep has been less accurately studied than nighttime sleep. This study aims to explore the relationship between diurnal sleep habits in nursery settings, nocturnal sleep quality, and post-nap emotional intensity in infants and toddlers. Methods: Data of 92 children (52 girls, 40 boys) aged 6 to 36 months were obtained. Sleep habits as well as positive and negative emotions were monitored by educators during nursery times through a sleep and emotion diary for two weeks. Results: Explorative analyses showed that diurnal sleep hours decreased across age groups (except for females aged 25–36 months) and that all age groups had a lower amount of nocturnal sleep than is recommended by the National Sleep Foundation. Partial correlation analysis showed significant correlation between daytime sleep onset latency and positive emotions. Mediation analyses showed that daytime napping is relevant for emotional functioning independently of nocturnal sleep quality. Conclusions: Daytime sleep in early childhood seems to be linked to the management of positive and negative emotions and could play a role in healthy development of emotional processes.

Association of maternal sleep before and during pregnancy with preterm birth and early infant sleep and temperament

This study aimed to investigate the association of maternal sleep before and during pregnancy with preterm birth, infant sleep and temperament at 1 month of age. We used the data of the Japan Environment and Children’s Study, a cohort study in Japan, which registered 103,099 pregnancies between 2011 and 2014. Participants were asked about their sleep before and during pregnancy, and the sleep and temperament of their newborns at 1 month of age. Preterm birth data were collected from medical records. Maternal sleep was not associated with preterm birth, but subjective sleep quality during pregnancy was associated with late preterm birth (birth at 34–36 weeks of gestation). For example, participants with extremely light subjective depth of sleep were more likely to experience preterm birth (RR = 1.19; 95% confidence interval [CI] = 1.04–1.35). Maternal sleep both before and during pregnancy seemed to be associated with infant sleep and temperament at 1 month of age. Infants, whose mothers slept for less than 6 hours before pregnancy, tended to cry intensely (RR = 1.15; 95% CI = 1.09–1.20). Maternal sleep problems before and during pregnancy were associated with preterm birth and child sleep problems and temperament.

Mother's prenatal and postpartum depression symptoms and infant's sleep problems at 6 months

Mother's prenatal and postpartum depression have been associated with infant's sleep problems. This study aimed to analyze (a) the effects of mother's prenatal and postpartum depression symptoms, including the effects of prenatal and postpartum anxiety and depression scores of the Edinburgh Postnatal Depression Scale (EPDS), on infant's sleep problems at 6 months, and (b) the interaction effect between mother's prenatal and postpartum depression symptoms and infant's sex on infant's sleep problems at 6 months. The sample was comprised of 164 mother-infant dyads whose mothers completed measures of depression at the third trimester of pregnancy, 2 weeks, 3 and 6 months postpartum and a measure of infant's sleep problems at 6 months (CSHQ-I). Mother's prenatal depression symptoms, specifically depression scores of the EPDS, predicted more infant's sleep anxiety and daytime sleepiness, while mother's depression symptoms at 2 weeks postpartum, specifically anxiety scores of the EPDS, predicted more bedtime resistance and CSHQ-I total scores at 6 months. Boys of mothers with more prenatal depression symptoms presented more sleep anxiety at 6 months. Both mother's prenatal and early postpartum depression symptoms have a negative effect on the emergence of infant's sleep problems. Additionally, boys seem more vulnerable to mother's prenatal depression symptoms.

The effect of two types of minimal acupuncture on stooling, sleeping and feeding in infants with colic: secondary analysis of a multicentre RCT in Sweden (ACU-COL)

Background

Evidence for the effect of minimal acupuncture in infants with colic is limited.

Aim

To compare the effect of standardized minimal acupuncture, individualized acupuncture (where traditional acupuncture points were chosen according to the infant’s symptoms) and no acupuncture on objective measures of stooling, feeding and sleeping in infants with colic (based on diaries) and perceived changes in these parameters (based on parental questionnaires).

Methods

This was a secondary analysis of a multicentre randomized controlled three-armed trial conducted in four counties in Sweden between January 2013 and May 2015 (ACU-COL). The effect on crying has already been published and showed a decrease in crying time for the acupuncture groups. Infants, 2–8 weeks old, who cried and fussed for more than 3 h/day for more than 3 days/week, and thereby fulfilled the criteria for infantile colic, received four extra visits to their ordinary child health centre. The infants (n = 147) were randomly allocated via a computer-generated list to standardized minimal acupuncture at LI4 for 5 s (group A, n = 48), semi-standardized individual acupuncture with a maximum of five insertions for up to 30 s (group B, n = 49), or no acupuncture (group C, n = 48). The parents and the ordinary staff were blinded. Data were collected using: (1) diaries at baseline, during the two intervention weeks and 1-week follow-up; and (2) questionnaires with quantitative and qualitative components used at the second and fourth visits and during a follow-up telephone call. Outcomes were the changes in frequency of stooling and in hours of sleep per day.

Results

There were no differences between groups for stooling, feeding, or sleeping at any time point according to data from the diaries. At the follow-up phone call, more parents in groups A and B (compared to group C) perceived that feeding and sleep had changed and that the symptoms of colic had improved.

Maternal neglect and the serotonin system are associated with daytime sleep in infant rhesus monkeys

Environmental and biological factors contribute to sleep development during infancy. Parenting plays a particularly important role in modulating infant sleep, potentially via the serotonin system, which is itself involved in regulating infant sleep. We hypothesized that maternal neglect and serotonin system dysregulation would be associated with daytime sleep in infant rhesus monkeys. Subjects were nursery-reared infant rhesus macaques (n = 287). During the first month of life, daytime sleep-wake states were rated bihourly (0800-2100). Infants were considered neglected (n = 16) if before nursery-rearing, their mother repeatedly failed to retrieve them. Serotonin transporter genotype and concentrations of cerebrospinal fluid 5-hydroxyindoleacetic acid (5-HIAA) were used as markers of central serotonin system functioning. t tests showed that neglected infants were observed sleeping less frequently, weighed less, and had higher 5-HIAA than non-neglected nursery-reared infants. Regression revealed that serotonin transporter genotype moderated the relationship between 5-HIAA and daytime sleep: in subjects possessing the Ls genotype, there was a positive correlation between 5-HIAA and daytime sleep, whereas in subjects possessing the LL genotype there was no association. These results highlight the pivotal roles that parents and the serotonin system play in sleep development. Daytime sleep alterations observed in neglected infants may partially derive from serotonin system dysregulation.

Sleep quality buffers the effects of negative social interactions on maternal mood in the 3-6 month postpartum period: a daily diary study

Sleep and social relationships are two key determinants of psychosocial health that undergo considerable change across the transition to motherhood. The current study investigated the bidirectional relationship between daytime Positive and Negative Social Interactions (PSIs & NSIs) and nighttime sleep quality on maternal mood across 1 week in the 3-6 month postpartum period. Sixty healthy, non-depressed first-time mothers completed 7-consecutive days of daily social interaction and sleep diaries. Results indicated that higher than average sleep quality buffered the effect of higher than average NSIs on maternal mood (i.e., buffered mood reactivity) and appeared to promote mood recovery following a particularly "bad day" (i.e., higher than average NSIs). In addition, although PSIs were more common than NSIs overall, the most frequent and positively rated PSIs were with baby as were the most frequent and negatively rated NSIs. To our knowledge, our results are the first to characterize the impact of PSIs on postpartum maternal mood, assess maternal-infant social interactions in daily diary study of postpartum social relationships, and demonstrate the role that maternal sleep quality plays in social discord-related mood reactivity and mood recovery processes in the 3-6 month postpartum period.

Children's Sleep Habits Questionnaire - Infant Version

OBJECTIVES

This study proposed a version of the Children's Sleep Habits Questionnaire for infants under 12 months (CSHQ-I).

METHODS

The sample was comprised of 299 infants, aged between 2 weeks and 12 months.

RESULTS

Exploratory factor analysis revealed four subscales: Bedtime Resistance, Sleep Anxiety, Positive Sleep Habits, and Daytime Sleepiness. The CSHQ-I total scale presented good test-retest reliability and internal consistency. The CSHQ-I also showed good concurrent validity, with significant associations found between the CSHQ-I total scale and subscales and a measure of infant sleep-wake behaviors.

CONCLUSIONS

The present study suggested the CSHQ-I as a reliable instrument to assess sleep problems in infants during the first year of life.

Sleep in the Postpartum: Characteristics of First-Time, Healthy Mothers

Goals for the present study were to (a) describe the sleep of healthy new mothers over a 6-month postpartum period, (b) examine how sleep quality relates to daytime levels of fatigue and sleepiness, and (c) evaluate the relationship between mothers' and infants' sleep parameters. The sample consisted of 37 healthy, partnered, first-time mothers who had experienced full-term vaginal birth and had a healthy infant. We investigated infants' sleep parameters and mothers' sleep, mood, and daytime functioning 2 and 6 months postpartum. We found that at 2 months postpartum, mothers reported sleeping 6 hours at night and just under one hour during the day. Despite relatively frequent nocturnal awakenings, mothers experienced minimal insomnia, nonrefreshing sleep, anxiety, depression, daytime sleepiness, or fatigue at either 2 or 6 months. The most robust relationship between mothers' and infants' sleep was in the number of nocturnal sleep-wake episodes. Of note is that none of the infant sleep parameters was related to mothers' anxiety, depression, fatigue, sleepiness, or nonrefreshing sleep at either time period. Our results indicate that (1) selected low risk new mothers are resilient in terms of sleep quality, daytime functioning, and mood and (2) these are independent of their infants' sleep parameters.

Exclusive breastfeeding at three months and infant sleep-wake behaviors at two weeks, three and six months

This study assessed infant sleep-wake behavior at two weeks, three and six months as function of feeding method at three months (exclusively breastfed, partially breastfed, and exclusively formula fed infants). Mothers of 163 first-born, full-term, normal birth weight, healthy infants completed socio-demographic, depression, anxiety, and infant sleep-wake behavior measures. No effects were found for sleep arrangements, depression or anxiety, on feeding methods and sleep-wake behavior at three months. At two weeks exclusively breastfed infants at three months spent more hours sleeping and less hours awake during the 24-h period than partially breastfed infants. At three months, exclusively breastfed infants had a shorter of the longest sleep period at night than exclusively formula fed infants. At six months, exclusively breastfed infants at three months spent more hours awake at night than partially breastfed infants, awake more at night than exclusively formula fed infants, and had a shorter sleep period at night than partially breastfed and exclusively formula fed infants. This study showed differences in sleep-wake behaviors at two weeks, three and six months, when exclusively breastfed infants are compared with partially breastfed and exclusively formula fed infants at three months, while no effects were found for sleep arrangements, depression or anxiety.