Reference values and changes in infant sleep-wake behaviour during the first 12 months of life: a systematic review

Infant and early childhood physical health assessments in the HEALthy Brain and Child Development (HBCD) Study

The HEALthy Brain and Child Development (HBCD) Study, a multi-site prospective longitudinal cohort study, will examine human brain, cognitive, behavioral, social and emotional development beginning prenatally and planned through early childhood. Many prenatal and early childhood exposures impact both later physical health and development. Moreover, early deficits in physical health, such as growth and vision, are associated with differences in brain development, language and cognitive functioning. For these reasons, the HBCD Study includes measures of early childhood physical health, many of which have clinical relevance, and are applicable for use as both predictors and outcomes. Study measures assess a broad range of physical health domains and include both objective measurement of child growth and health and subjective caregiver report of behaviors and attitudes about constructs known to influence growth and physical development. Lastly, we obtain caregiver report of the child's routine medical care as well as acute and chronic medical issues. We anticipate that these data will contextualize the impact of child physical growth and health on child brain development and function. In this report we present the rationale for each domain and an overview of the physical health measures included in the current HBCD Study protocol.

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.

Night-time sleep duration and postpartum weight retention in primiparous women

Objectives

Approximately 75% of women weigh more at 1-year postpartum than pre-pregnancy. More than 47% retain >10 lbs at 1-year postpartum, which is associated with adverse health outcomes for mother and child. Disturbed sleep may contribute to risk of postpartum weight retention (PWR) as short sleep duration is associated with increased risk of obesity. Thus, we investigated whether night-time sleep duration is associated with risk for excessive PWR. We also explored night-time sleep duration and change in postpartum waist circumference.

Methods

This is an ancillary analysis from a prospective cohort study. Participants were healthy primiparous adults with a singleton birth. Excessive PWR at 1-year postpartum was defined as ≥7% of pre-pregnancy weight. Log-binomial and linear regression assessed associations between night-time sleep duration at 6 months postpartum and PWR at 1-year postpartum. Linear regression assessed the association between night-time sleep duration and change in postpartum waist circumference.

Results

Mean age of participants (N = 467) was 29.51 (SD ± 4.78) years. Night-time sleep duration by actigraphy or self-report was not associated with risk for excessive PWR (risk ratio 0.96, [95%CI 0.87-1.06]; risk ratio 0.95 [95%CI 0.83-1.07], respectively) or change in waist circumference.

Conclusion

Night-time sleep duration at 6 months postpartum was not associated with PWR at 1-year postpartum. Mixed findings among our results and previous research could be due to our focus on night-time sleep, and differences in sleep measurement methods and timeframes across studies. More comprehensively assessing sleep, including multiple sleep dimensions, may help advance our understanding of potential links between sleep and PWR.

Trial Registration

The parent study, Motherhood and Pelvic Health (MAP Study), is registered at https://clinicaltrials.gov/ct2/show/NCT02512016, NCT02512016.

Life satisfaction in parents after successful in vitro fertilization and natural pregnancy: a prospective longitudinal study from before pregnancy to 24 months after childbirth

Changes in psychological variables in couples after successful in-vitro fertilization (IVF) have rarely been investigated. This paper describes follow-up assessments of a previously published study investigating changes in life satisfaction, stress and worry related to childbirth in couples undergoing IVF and those with natural pregnancy. Questionnaire data were obtained in 75 IVF couples and 70 couples with natural pregnancy before pregnancy, and at 6 and 12 months postpartum; follow-up data were recorded 18 and 24 months postpartum. IVF couples had less favourable baseline scores for all variables than those with natural pregnancy. Their life satisfaction increased, stress and worry decreased, during the first year postpartum. Couples with natural pregnancy reported transient worsening in all variables during this period. During follow-up, all variables remained largely stable in both groups; while life satisfaction and stress no longer differed between groups, worry was lower in IVF couples at month 24. Gender differences were small in both groups. In IVF couples, negative impacts of infertility may fully abate after childbirth; in naturally conceiving couples, initial negative changes in wellbeing are reversed and stabilized during the child´s first 2 years. Both groups may benefit from psychological support at different times during pregnancy and parenthood.

A longitudinal study of infant 24-hour sleep: comparisons of sleep diary and accelerometer with different algorithms

STUDY OBJECTIVES

To longitudinally compare sleep/wake identification and sleep parameter estimation from sleep diaries to accelerometers using different algorithms and epoch lengths in infants.

METHODS

Mothers and other caregivers from the Nurture study (southeastern United States, 2013-2018) reported infants' 24-hour sleep in sleep diaries for 4 continuous days, while infants concurrently wore accelerometers on the left ankle at 3, 6, 9, and 12 months of age. We applied the Sadeh, Sadeh Infant, Cole, and Count-scaled algorithm to accelerometer data at 15 and 60 seconds epochs. For sleep/wake identification, we assessed agreement by calculating epoch-by-epoch percent agreement and kappas. We derived sleep parameters from sleep diaries and accelerometers separately and evaluated agreement using Bland-Altman plots. We estimated longitudinal trajectories of sleep parameters using marginal linear and Poisson regressions with generalized estimation equation estimation.

RESULTS

Among the 477 infants, 66.2% were black and 49.5% were female. Agreement for sleep/wake identification varied by epoch length and algorithm. Relative to sleep diaries, we observed similar nighttime sleep offset, onset, and total nighttime sleep duration from accelerometers regardless of algorithm and epoch length. However, accelerometers consistently estimated about 1 less nap per day using the 15 seconds epoch, 70 and 50 minutes' shorter nap duration per day using the 15 and 60 seconds epoch, respectively; but accelerometers estimated over 3 times more wake after nighttime sleep onset (WASO) per night. Some consistent sleep parameter trajectories from 3 to 12 months from accelerometers and sleep diaries included fewer naps and WASOs, shorter total daytime sleep, longer total nighttime sleep, and higher nighttime sleep efficiency.

CONCLUSIONS

Although there is no perfect measure of sleep in infancy, our findings suggest that a combination of accelerometer and diary may be needed to adequately measure infant sleep.

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.

[Cross-sectional study on the sleep status and risk factors for sleep problems in infants and young children in Jilin Province]

OBJECTIVES

To explore the sleep status and risk factors for sleep problems in infants and young children in Jilin Province.

METHODS

A total of 1 080 healthy infants and young children aged 0-3 years from eight prefecture-level cities and one autonomous prefecture in Jilin Province were selected as subjects. A self-designed questionnaire was used to collect the general information of the subjects, and the Brief Infant Sleep Questionnaire was used to understand the sleep status of the subjects. Multivariate logistic regression analysis was used to analyze the risk factors for sleep problems.

RESULTS

The total detection rate of sleep problems in the infants and young children was 38.24% (413/1 080). The total sleep time in the 4-11 month, 12-24 month, and 25-36 month age groups was higher than the recommended total sleep time (P<0.05). Multivariate logistic regression analysis showed that full-term birth, higher educational level of the main caregiver, and higher daytime activity intensity were protective factors for sleep problems in the infants and young children (P<0.05), while lower frequency of vitamin D supplementation, frequent night feeding, and maternal snoring were risk factors for sleep problems (P<0.05).

CONCLUSIONS

The total sleep time of infants and young children over 4 months old in Jilin Province is higher than the recommended total sleep time, but the prevalence rate of sleep problems is higher. The occurrence of sleep problems is related to various factors. Strengthening follow-up on preterm infants, providing education on infant sleep knowledge to primary caregivers, and regularly supplementing with vitamin D can be beneficial in reducing sleep problems in infants and young children.

The sleep and wake electroencephalogram over the lifespan

Both sleep and wake encephalograms (EEG) change over the lifespan. While prior studies have characterized age-related changes in the EEG, the datasets span a particular age group, or focused on sleep and wake macrostructure rather than the microstructure. Here, we present sex-stratified data from 3372 community-based or clinic-based otherwise neurologically and psychiatrically healthy participants ranging from 11 days to 80 years of age. We estimate age norms for key sleep and wake EEG parameters including absolute and relative powers in delta, theta, alpha, and sigma bands, as well as sleep spindle density, amplitude, duration, and frequency. To illustrate the potential use of the reference measures developed herein, we compare them to sleep EEG recordings from age-matched participants with Alzheimer's disease, severe sleep apnea, depression, osteoarthritis, and osteoporosis. Although the partially clinical nature of the datasets may bias the findings towards less normal and hence may underestimate pathology in practice, age-based EEG reference values enable objective screening of deviations from healthy aging among individuals with a variety of disorders that affect brain health.

Designing an App for Parents and Caregivers to Promote Cognitive and Socioemotional Development and Well-being Among Children Aged 0 to 5 Years in Diverse Cultural Settings: Scientific Framework

Recent years have seen remarkable progress in our scientific understanding of early childhood social, emotional, and cognitive development, as well as our capacity to widely disseminate health information by using digital technologies. Together, these scientific and technological advances offer exciting opportunities to deliver high-quality information about early childhood development (ECD) to parents and families globally, which may ultimately lead to greater knowledge and confidence among parents and better outcomes among children (particularly in lower- and middle-income countries). With these potential benefits in mind, we set out to design, develop, implement, and evaluate a new parenting app-Thrive by Five-that will be available in 30 countries. The app will provide caregivers and families with evidence-based and culturally appropriate information about ECD, accompanied by sets of collective actions that go beyond mere tips for parenting practices. Herein, we describe this ongoing global project and discuss the components of our scientific framework for developing and prototyping the app's content. Specifically, we describe (1) 5 domains that are used to organize the content and goals of the app's information and associated practices; (2) 5 neurobiological systems that are relevant to ECD and can be behaviorally targeted to potentially influence social, emotional, and cognitive development; (3) our anthropological and cultural framework for learning about local contexts and appreciating decolonization perspectives; and (4) our approach to tailoring the app's content to local contexts, which involves collaboration with in-country partner organizations and local and international subject matter experts in ECD, education, medicine, psychology, and anthropology, among others. Finally, we provide examples of the content that was incorporated in Thrive by Five when it launched globally.

Prospective association of short sleep duration in newborns with bruxism behavior in children: The Japan Environment and Children's Study (JECS)

BACKGROUND

Bruxism is defined as a repetitive masticatory muscle activity, characterized by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible. Although the bruxism etiology can be bidirectionally described with sleep disorders, there are few studies available to understand the association of sleep duration with bruxism behavior in early childhood.

METHODS

A dataset of children (n = 90,148) from the Japan Environment and Children's Study (JECS) - an ongoing nationwide, prospective birth cohort study - was used to investigate the prospective association of the infant's sleep duration with bruxism behavior, which were acquired using self-reported questionnaire. After multiple imputation of data, the association between sleep duration and bruxism behavior in early childhood was examined using a binomial logistic regression analysis. It was conducted with adjustments for several maternal (e.g., age at delivery and sleep duration) and child-related (e.g., sex and sleep position) variables.

RESULTS

The prevalence of bruxism behavior at the ages of two and four were 16.2% and 22.5%, respectively. Using the shortest sleep duration group's participants (≤13 h) as the reference, the odds ratio (95% confidence interval) for prevalence of bruxism behavior decreased with longer sleep duration at one month of age, but not at 36 months of age, after covariate adjustments. Furthermore, in comparison with the impacts between daytime and nighttime sleep, nighttime sleep with longer duration were dominantly associated with bruxism behavior.

CONCLUSION

The sleep duration in infant stage, especially during newborn stage was associated with the prevalence of bruxism behavior in children.

Breastfeeding and Maternal Perceptions of Infant Sleep, Settle and Cry Patterns in the First 9 Months

This study evaluated relationships between maternal perceptions of infant sleep, settling and crying patterns and breastfeeding. A prospective observational study of 91 mothers of healthy, term infants was conducted with follow ups over 9 months after discharge from a Western Australian maternity hospital. Feeding information, sleep, settle and cry behaviours, maternal bother at infant behaviours and confidence were measured using the Sleep and Settle Questionnaire. Breastfeeding confidence was measured using the Breastfeeding Self-Efficacy Scale-Short Form. Questionnaires were administered at 2 and 6 weeks, 3, 6 and 9 months. Linear mixed models were used to assess associations between maternal bother, feeding method and infant characteristics. The feeding method was not associated with maternal bother, and cessation of breastfeeding did not result in a change in bother scores (p = 0.34). Duration of infant crying in the day, evening and night, frequency of night waking and duration of settling to sleep in the day were associated with increased bother scores. Higher breastfeeding self-efficacy and maternal confidence were associated with lower bother scores (both p < 0.01). Maternal bother is associated with infant behaviours that require parental input, but not breastfeeding status. Resources that address parental expectations regarding infant sleep while providing strategies to support maternal wellbeing and breastfeeding are needed.

The Use of Caregivers’ Smartphones to Assist Infants’ Circadian Sleep–Wake Cycles

Parents and caregivers lack knowledge regarding young children’s sleep routines due to an absence of general guidelines about sleep development, and this knowledge gap has been associated with infants’ sleep problems. Approximately 30% of infants develop sleep problems, including difficulty with falling asleep and night-waking. In this study, we sought to develop a new indicator of regularity in infants’ circadian sleep–wake patterns. Our participants were healthy Japanese mothers and their infants ( n = 172 infants; Mage = 4.9, SD = 3.5 months). Mothers used their smartphones to record the time when their infants fell asleep and woke up in their natural home environments over 7 days. We conducted least-squares spectrum analysis, a time-series analysis often used in chronobiology, to calculate the percentage variance (PVA) of the best-fitted cosine waves with a 24-hr periodicity in the infants’ sleep records. We found that the PVA of the 24-hr cycles in the infants’ sleep records were significantly correlated with the infants’ age in months ( r = 0.554, p < 0.001), variations in their waking-up ( r = −0.316, p < 0.001) and falling asleep times ( r = −0.430, p < 0.001), and sleep duration ( r = −0.343, p < 0.001). Apart from these normative data, which are of potential comparative use by other investigators, we showed in this study that PVA data can be collected by infants’ parents and caretakers through smartphones to provide parents an indicator of the regularity of an infant’s 24-hr periodicity.

Perceived Sleep Quality and Fatigue in a Population of New Mothers: A Cross-Sectional Study Comparing Relationships with Breastfeeding and Bottle Feeding

Introduction: This study, which used a cross-sectional design, was carried out to examine the factors associated with the way mothers fed their infants such as breastfeeding or bottle feeding, and to compare perceived sleep quality and fatigue levels. Method: The study sample consisted of a total of 100 women in the 4th to 16th week postpartum, including 50 women breastfeeding and 50 women bottle feeding their infants. The data of the study were collected in Family Health Centers (FHC) through the face-to-face interview technique using "a Personal Information Form," "the Pittsburgh Sleep Quality Index-PSQI," and "the Checklist Individual Strength-CIS." Results: The mothers' total sleep quality (PSQI) score was found to not differ significantly according to the type of infant feeding. Similarly, total scores for fatigue assessment obtained from the CIS did not differ according to the infant feeding type variable. A significant positive correlation was found between total sleep quality and total fatigue level, and subjective fatigue level. Discussion: The sleep quality and fatigue levels of mothers are independent of the method of feeding their infants. Midwives should plan initiatives with parents to improve maternal sleep quality and reduce fatigue levels and inform parents that breastfeeding is not a factor that reduces sleep quality or increases fatigue. Clinical Trials.gov ID: 1129/5463.

Type of Milk Feeding and Introduction to Complementary Foods in Relation to Infant Sleep: A Systematic Review

Inconsistent conclusions from infant sleep and feeding studies may influence parents feeding-related decisions. This study aimed to systematically review the existing literature on infant sleep and its relation to the timing of introduction to complementary foods and type of milk feeding to better understand their role(s) in infant sleep. Cohort, longitudinal, cross-sectional studies, and controlled trials were identified using online searches of five databases up to April 2020. Twenty-one articles with a total of 6225 infants under 12 months-of-age were eligible. Exclusively breastfed infants (≤6 months-of-age) had a greater number of night wakings, but most studies (67%) reported no difference in night-time and 24 h sleep duration compared to formula-fed infants. However, after 6 months-of-age, most studies (>65%) reported breastfed infants to sleep less in the night-time and over 24 h compared to formula-fed infants. Furthermore, studies reported no association between the timing of introduction to complementary foods and infant sleep duration (<12 months-of-age). Future studies using standardized methodologies and definitions, transdisciplinary expertise, and longitudinal design are required to better understand the complex role of feeding on 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.

Association between breastfeeding and new mothers' sleep: a unique Australian time use study

BACKGROUND

Infant sleep is of great interest to new parents. There is ongoing debate about whether infants fed with breastmilk substitutes sleep longer than those exclusively or partially breastfed, but what does this mean for the mother? What expectations are realistic for mothers desiring to exclusively breastfeed as recommended by health authorities? There are both biological and social influences on infant and maternal sleep. More accurate information on average maternal sleep hours for diverse feeding practices may help guide realistic expectations and better outcomes for mothers, infants and families.

METHODS

Using a unique time use dataset purposefully designed to study the time use of new mothers, this study investigated whether the weekly duration of maternal sleep, sleep disturbance, unpaid housework, and free time activities differed by detailed feeding method. The study collected 24/7 time use data from 156 mothers of infants aged 3, 6 and/or 9 months between April 2005 and April 2006, recruited via mother's groups, infant health clinics, and childcare services throughout Australia. Sociodemographic and feeding status data were collected by questionnaire. Statistical analysis used linear mixed modelling and residual maximum likelihood analysis to compare effects of different infant feeding practices on maternal time use.

RESULTS

There were no significant differences in time spent asleep between lactating and non lactating mothers, though lactating mothers had more time awake at night. Lactating mothers spent more time (8.5 h weekly) in childcaring activity (p = 0.007), and in employment (2.7 vs. 1.2 h, p < 0.01), but there were no significant differences in free time. Those not breastfeeding spent more time in unpaid domestic work. Exclusive breastfeeding was associated with reduced maternal sleep hours (average 7.08 h daily). Again, free time did not differ significantly between feeding groups. Exclusively breastfeeding mothers experienced reduced sleep hours, but maintained comparable leisure time to other mothers by allocating their time differently. Domestic work hours differed, interacting in complex ways with infant age and feeding practice.

CONCLUSIONS

Optimal breastfeeding may require realistic maternal sleep expectations and equitable sharing of paid and unpaid work burdens with other household members in the months after the birth of an infant.

Infant feeding practices and sleep at 1 year of age in the nationwide ELFE cohort

Sleep problems reported by parents affect 20% to 30% of infants. Few studies focused on the longitudinal association between infant feeding practices and sleep, especially in France. Analyses were based on 8,696 infants from the French national birth cohort ELFE. Collection of feeding practices from birth to 10 months allowed for the identification of trajectories of use of baby cereals and thickened formula by group‐based trajectory modelling and calculation of duration of any breastfeeding (BF) and age at complementary feeding introduction (CFI) excluding baby cereals. Total sleep duration (TSD), night waking (NW) and sleep onset difficulties (SOD) were reported at age 1. Associations between feeding and sleep were tested by multinomial logistic regressions. BF duration ≥6 months was associated with parent‐reported frequent NW, SOD and TSD ≤ 12 h/24 h at age 1. For TSD and SOD, this association was no longer significant after accounting for parental sleep‐related practices. Early use of baby cereals (≤5 months) was associated with poor sleep. Early CFI (<4 months) was associated with shorter TSD and SOD but not NW. Early use of thickened formula (only <6 months) was related to poor sleep at age 1 (NW and SOD), whereas late (around 6 months) use of thickened formula was associated with better sleep. BF duration ≥6 months was related to poor sleep at age 1 but not after adjustment on 1‐year parental sleep‐related practices except for NW. The use of baby cereals or early CFI was not related to better sleep at age 1.

Time for bed! Earlier sleep onset is associated with longer nighttime sleep duration during infancy

OBJECTIVE/BACKGROUND

Clinical recommendations include putting infants to bed using a consistent bedtime routine at an appropriate hour to promote longer nighttime sleep. Actigraphy was used in this exploratory study to examine how bedtime routines and nighttime sleep onset were associated with nighttime total sleep time (TST) and efficiency from 6 to 24 weeks of age.

PATIENTS/METHODS

Infants (n = 24) wore sleep actigraphs for three, one-week periods at 6, 15, and 24 weeks of age. Nighttime TST, sleep efficiency, sleep onset and offset were quantified. Mothers reported on infant bedtime routines using the Brief Infant Sleep Questionnaire at each age. Multilevel models examined between- and within-person associations.

RESULTS

As infants aged, sleep onset was earlier, and bedtime routines became shorter (p's < 0.05). Infants fell asleep between 7 and 8:00PM on 24% of the nights. Most mothers (70%) reported that they often fed infants to sleep for the night. For every 1 h earlier in infants' usual sleep onset, nighttime TST was 34.4 min longer that night (p < 0.01). Infants with earlier than usual sleep onset had slightly earlier sleep offset the next morning (8.4 min for every 1 h earlier in onset; p = 0.02). Between-person analyses showed similar patterns. Infants with a more consistent bedtime routine and who were not typically fed to sleep at bedtime had longer nighttime TST at 6 weeks, with a trend or no association at later ages.

CONCLUSION

Infants who fell asleep earlier also slept longer at night. Keeping infants up later in hopes of them sleeping in longer may be counterproductive.

Sleep habits and sleep characteristics at age one year in the ELFE birth cohort study

OBJECTIVE

Infant sleep plays a critical role in normal development. Sleep problems, including sleep onset difficulties (SODs) and night waking (NW), range from 20% to 30% in infants and young children and can be persistent over time up to adulthood. Young French children seem to have longer sleep durations and less sleep troubles than their counterparts worldwide. Here, we aimed at describing infant sleep characteristics (total sleep time (TST)/24 h, NW, and SODs) and associated sleep habits in infants at age one year from the French nationwide birth cohort Etude Longitudinale Française depuis l'Enfance (ELFE).

METHODS

This study included 11,783 infants with information on both sleep characteristics and sleep habits (parental presence when falling asleep, eating to fall asleep, sucking a pacifier or finger to sleep and sleep arrangement and location). Associations were studied by multinomial logistic regression analyses adjusted for familial and infant characteristics.

RESULTS

Mean TST was 13 h36 min including 2 h54 min of naps; 20% of the infants had TST ≤12 h/24 h. About 46% did not present SOD or NW, 16% had frequent SODs and 22% had NW > 1 night in 2. Parental presence, feeding to fall asleep and infant sleep arrangements were frequent in infants with short sleep duration (≤12 h/24 h), NW and SODs. Non-nutritive sucking was associated with risk of NW, SOD and TST >14 h/24 h. Parental room sharing was associated with NW.

CONCLUSION

This work provides new information on infant sleep arrangements and non-nutritive sucking that should be accounted for when considering sleep behaviors. In addition, most identified sleep habits associated with poor sleep characteristics may be amenable to change.

Appropriate age range for introduction of complementary feeding into an infant's diet

Following a request from the European Commission, the Panel on Nutrition, Novel Foods and Food Allergens (NDA) revised its 2009 Opinion on the appropriate age for introduction of complementary feeding of infants. This age has been evaluated considering the effects on health outcomes, nutritional aspects and infant development, and depends on the individual's characteristics and development. As long as foods have an age-appropriate texture, are nutritionally appropriate and prepared following good hygiene practices, there is no convincing evidence that at any age investigated in the included studies (< 1 to < 6 months), the introduction of complementary foods (CFs) is associated with adverse health effects or benefits (except for infants at risk of iron depletion). For nutritional reasons, the majority of infants need CFs from around 6 months of age. Infants at risk of iron depletion (exclusively breastfed infants born to mothers with low iron status, or with early umbilical cord clamping (< 1 min after birth), or born preterm, or born small-for-gestational age or with high growth velocity) may benefit from earlier introduction of CFs that are a source of iron. The earliest developmental skills relevant for consuming pureed CFs can be observed between 3 and 4 months of age. Skills for consuming finger foods can be observed in some infants at 4 months, but more commonly at 5-7 months. The fact that an infant may be ready from a neurodevelopmental perspective to progress to a more diversified diet before 6 months of age does not imply that there is a need to introduce CFs. There is no reason to postpone the introduction of potentially allergenic foods (egg, cereals, fish and peanut) to a later age than that of other CFs as far as the risk of developing atopic diseases is concerned. Regarding the risk of coeliac disease, gluten can be introduced with other CFs.

Cross-cultural disparities of subjective sleep parameters and their age-related trends over the first three years of human life: A systematic review and meta-analysis

Changes in nighttime sleep consolidation and daytime discontinuation have been observed in early life. Yet information about societal or cultural factors remains scant for implementing sleep recommendations. We aimed to provide pooled estimates of subjective sleep duration, number of nightwakings and sleep timing; to describe their age-related trends; and to determine potential cross-cultural disparities between predominantly-Asian (PA) and predominantly-Caucasian (PC) regions during the first three years of life. We performed this review according to the PRISMA guidelines. Overall, 102 studies with 167,886 children aged 0-3 y from 26 different countries/regions were included. Compared to PC regions, PA toddlers had shorter sleep duration and more frequent nightwakings. When PC regions were further divided into Pacific Rim and Europe, differences were much more evident between PA and Pacific Rim for all nighttime sleep parameters. Trends of nighttime sleep duration and bedtime for PC regions showed rapid changes over the first 3-6 mo before stabilizing to a plateau, whereas a different change was found for PA regions. In conclusion, an apparent cross-cultural disparity of the subjective sleep parameters already exists in early childhood. Improved operationalization of sleep parameters and more objective evidence are needed to establish cultural-sensitive recommendations this early in life.

Physical activity and objectively assessed sleep in 6-month-old infants in Taiwan

Adequate physical activity is associated with improved sleep in adults. Such associations, however, vary greatly across studies in pediatric populations, with no studies involving infants found in the literature. This prospective observational study was designed, therefore, to examine the association between physical activity and sleep patterns in infants. A total of 183 healthy infants aged 6 months wore an actigraph for 7 days to measure physical activity and sleep. Parents and caregivers completed a sleep-activity diary over the same period documenting the different types of infant activities. Daily mean time spent in screen-time-or-limited physical activity, including screen-based (e.g., watching television or other electronic devices) and non-screen based activity (e.g., quiet play or restricted infant movement when carried by caregivers or seated in high chairs, swings, or bouncer seats), was 6.68 hr (SD = 1.99), which represented 47.50% of daytime waking hours (SD = 13.73). We found that 65 (35.5%) infants engaged in some screen time during the study, with 10 (5.5%) infants having an average daily screen time >30 min. In our multivariate linear regression model, more hours of screen-time-or-limited physical activity per day were significantly associated with a decrease in total daily 24 hr sleep duration (p < 0.01). Findings from our study suggest that reducing screen-time-or-limited physical activity might be an approach for promoting adequate sleep and lengthening infant daily sleep duration.