Infant feeding type and maternal sleep during the postpartum period: a systematic review and meta-analysis

The aim of this meta-analysis was to examine the associations among infant feeding types, sleeping habits, and maternal sleep postpartum. Databases including Cumulative Index of Nursing and Allied-Health Literature (CINAHL), PubMed, and Google Scholar were searched in addition to reference lists from selected articles and other key references. A critical review of relevant articles from the data sources was conducted with attention to the infant feeding types and maternal night-time sleep. The methodological quality was assessed systematically. The pooled mean difference was calculated. Narrative summaries were also used. A total of 6,472 participants from seven studies were included in the meta-analysis. A random-effects model demonstrated a significantly higher maternal night-time sleep in breastfeeding mothers than non-breastfeeding mothers with a pooled standardized mean difference of 0.24 h (95% confidence interval 0.03–0.46, p = 0.026). Co-sleeping with infants during the night also increased the sleeping hours in breastfeeding mothers. Homogeneity was observed with a Tau² of 0.0308 and I² of 44.3%. Funnel plots, Egger's and Begg's tests revealed no evidence of publication bias. This systematic review and meta-analysis demonstrated that breastfeeding may be associated with a longer night-time sleep postpartum and the synthesis of the literature suggested that co-sleeping with the infant was associated with longer sleep duration in breastfeeding women. Further research into factors involving maternal decisions on infant feeding types and their effects on maternal sleep is needed to better understand the mothers' attitude toward infant feeding and their own sleep.     

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

This paper is a systematic review on the reference values and changes in infant sleep–wake behaviour during the first 12 months of life. This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta‐Analysis (PRISMA). Seventy‐four papers were included, and the reference values and changes in sleep–wake behaviour during the first 12 months of life were identified. Sleep duration during the 24‐h period, and day and sleep periods during the night decreased over the first 12 months of life. Night wakings and bedtime/sleep‐onset time decreased, while the longest sleep period increased at night during the first 6 months. High discrepancy was noted between studies in the reference values of sleep–wake behaviour, while more congruence was noted regarding changes, especially those occurring in the first 6 months of life. Several methodological differences were identified between studies and may partially explain inconsistencies in the results, including the assessment of different sleep–wake behaviours, the focus on specific ages or age ranges, the use of self‐report, observational or direct measures, the recruitment of small or large representative samples, and the countries where the research was conducted. These aspects should be considered in future research and caution should be taken when generalizing results from studies with diverse methodological characteristics. Nonetheless, this review identifies normative reference values and the changes occurring in infant sleep–wake behaviour, and could inform both practitioners and researchers, helping them identify infants with sleep delays or problems.     

The association between infant feeding practices and subsequent atopy among children with a family history of asthma

BACKGROUND: Although longer duration of breastfeeding and later introduction of solid foods are both recommended for the prevention of asthma and allergic disease, evidence to support these recommendations is controversial. OBJECTIVE: To examine the relation between infant feeding practices and the risk of asthma and allergic disease at age 5 years. METHODS: A cohort of children with a family history of asthma in Sydney, Australia, was followed from birth to age 5 years. Data on infant feeding practices and on early manifestations of eczema were collected prospectively. The presence of eczema, asthma and atopy (positive allergen skin prick tests) were determined at age 5 years. RESULTS: In 516 children evaluated at age 5 years, there was no significant association between the duration of breastfeeding or timing of introduction of solid foods and protection against asthma or other allergic disease, after adjustment for confounding factors. However, breastfeeding for 6 months or more and introduction of solid foods after 3 months were both associated with an increased risk of atopy at age 5 years (P=0.02 and 0.01, respectively). There was no significant association between the presence of eczema at 4 weeks and at 3 months and continued breastfeeding beyond those times. CONCLUSION: Longer duration of breastfeeding and later introduction of solid foods did not prevent the onset of asthma, eczema or atopy by age 5 years.     

Twenty‐four‐hour motor activity and body temperature patterns suggest altered central circadian timekeeping in Smith–Magenis syndrome,a neurodevelopmental disorder

Smith–Magenis syndrome (SMS) is a contiguous gene syndrome linked to interstitial microdeletion, or mutation of RAI1, within chromosome 17p11.2. Key behavioral features of SMS include intellectual disability, sleep‐disturbances, maladaptive, aggressive and self‐injurious behaviors, hyperactivity, and sudden changes in mood. A distinguishing feature of this syndrome is an inverted pattern of melatonin characterized by elevated daytime and low nighttime melatonin levels. As the central circadian clock controls the 24‐hr rhythm of melatonin, we hypothesized that the clock itself may contribute to the disrupted pattern of melatonin and sleep. In this report, 24‐hr patterns of body temperature, a surrogate marker of clock‐timing, and continuous wrist activity were collected to examine the links between body temperature, sleep behavior, and the circadian clock. In addition, age‐dependent changes in sleep behavior were explored. Actigraphy‐estimated sleep time for SMS was 1 hr less than expected across all ages studied. The timing of the 24‐hr body temperature (Tb‐24) rhythm was phase advanced, but not inverted. Compared to sibling (SIB) controls, the SMS group had less total night sleep, lower sleep efficiency, earlier sleep onset, earlier final awake times, increased waking after sleep onset (WASO), and increased daytime nap duration. The timing of wake onset varied with age, providing evidence of ongoing developmental sleep changes from childhood through adolescence. Clarification of the circadian and developmental factors that contribute to the disrupted and variable sleep patterns in this syndrome will be helpful in identifying more effective individualized treatments.     

Pacifier Use,Finger Sucking,and Infant Sleep

Few studies to date have investigated the relationship between pacifier use or finger sucking and infant sleep. One hundred and four mothers of infants (ages 0–11 months) completed the Brief Infant Sleep Questionnaire (BISQ). Infants who engaged in finger sucking had fewer night wakings and longer stretches of nighttime sleep, although less daytime sleep. There were no significant differences in sleep patterns between pacifier users and infants who did not engage in nonnutritive sucking. Furthermore, no significant differences were found across groups for sleep ecology, including parental involvement at bedtime and following night wakings. Finally, infants were consistently able to retrieve their pacifiers independently by 7 months of age, although this did not appear to be associated with sleep outcomes. Results suggest that when parents are deciding whether to give their infant a pacifier, sleep may not be a critical factor. In contrast, parents of finger and thumb suckers should be reassured that this nonnutritive sucking is beneficial to sleep, at least in the first year of life.     

Development of infant and toddler sleep patterns: real‐world data from a mobile application

The aim of this study was to investigate the development of infant and toddler sleep patterns. Data were collected on 841 children (aged from birth to 36 months) via a free, publicly available, commercially sponsored iPhone app. Analyses were conducted on caregiver recordings of 156 989 sleep sessions across a 19‐month period. Detailed visualizations of the development of sleep across the first 3 years of life are presented. In the first 3 months, sleep sessions primarily lasted less than 3.5 h throughout the day. Between 3 and 7 months old, sleep consolidated into two naps of about 1.5 h in length and a night‐time sleep session of about 10.5 h. Across age groups, a negative relationship was observed between the start of bedtime and the length of the night‐time sleep session (i.e. later bedtime is associated with a shorter night‐time sleep period). The length of daytime sleep sessions (naps) varied with age, decreasing between 1 and 5 months old, and then increasing monotonically through 28 months. Morning wake time was observed to be invariant in children aged 5–36 months. Sleep patterns are ever‐changing across the first few years with wide individual variability. Sleep patterns start to develop more clearly at 5–6 months, when longer night‐time sleep duration begins and sleep consolidation occurs. Daytime sleep patterns appeared to become more consistent and consolidated later in age than night‐time sleep. Finally, there is greater variability in bedtimes than wake times, with bedtimes having a greater influence on night‐time sleep duration.     

Sleep problems in children with autism

Autism is a developmental disability characterized by severe deficits in social interaction and communication, and the presence of repetitive-ritualistic behaviors. Sleep problems are frequently reported by parents of children with autism with prevalence estimates of 44-83% for sleep disorders in this population. To better understand sleep in autism, we surveyed sleep problems in 210 children with autism using a Likert-based questionnaire for parent report. The most frequently reported sleep problems included difficulty in falling asleep, restless sleep, not falling asleep in own bed, and frequent wakenings. Least frequently reported sleep problems were sleep walking, morning headaches, crying during sleep, apnea, and nightmares. When surveys were divided into mental retardation (MR)/not MR categories, no significant differences were identified in frequencies of reported sleep problems except for waking at night which occurred much more frequently in the MR group. There was also no difference in sleep problems related to age of the child other than nocturnal enuresis. An association was noted between certain medical problems and sleep problems. Vision problems, upper respiratory problems, and runny nose were associated with decreased nighttime sleep. Vision problems, poor appetite, and poor growth were associated with increased nighttime waking. Poor appetite and poor growth were associated with decreased willingness to fall asleep. This study confirms a high prevalence of sleep problems reported by parents of children with autism and points to the need for more systematic research as an initial step in developing treatment strategies.     

Objectively measured night‐to‐night sleep variations are associated with body composition in very elderly women

This cross‐sectional study examined the association between objectively measured sleep patterns and body composition in very elderly community‐dwelling women. Participants included 191 community‐dwelling adults aged ≥ 80 years (mean age: 83.4 ± 2.6 years; age range: 80–92 years). Sleep and physical activity were monitored via accelerometer (ActiGraph GT3X+) during at least five consecutive 24‐h periods. Night‐to‐night sleep pattern variability across all nights of recording was assessed using standard deviations (SDs). Body composition was assessed using dual‐energy X‐ray absorptiometry. Simple and multivariable linear regression analyses were performed. The mean number of nights with usable actigraphy data was 7.3 ± 1.3. On average, participants went to bed at 22:57 hours (SD: 1.11 h) and rose from bed at 6:27 hours (SD: 1.01 h). Night‐to‐night bedtime, sleep duration and sleep timing mid‐point variations correlated slightly with the percentage body fat and percentage lean mass (P < 0.05). Multiple linear regression analysis revealed significant associations of night‐to‐night bedtime variations and inconsistent sleep–wake patterns with all body composition indices after adjusting for potential confounding factors, including mean nightly sleep duration, self‐reported nap duration and daily physical activity. After further adjusting for night‐to‐night wake time, sleep timing mid‐point and sleep duration variations, greater bedtime variability remained associated significantly with all body composition indices except lean/fat mass ratio. Inconsistent sleep–wake patterns were associated independently with an increased fat mass and decreased lean mass among very elderly women. These findings suggest that in most elderly individuals, sleep patterns might be an important modifiable factor associated with obesity and sarcopenia development.     

Perinatal predictors of sleep disturbances in young infants

The study aimed to identify risk factors of sleep disturbances in 2-month-old infants. It comprised 198?infants (86?boys, 112?girls) who were singletons born in St. Petersburg, Russia, in?2007. The mothers were asked to complete questionnaires addressing major infant, maternal, and demographic characteristics. Preexisting medical records were scrutinized. The mothers were requested to describe infant sleep troubles. The baby was defined as having sleep disturbances, if he or she had five or more episodes per week characterized by settling difficulties at bedtime (could not fall asleep within 20?minutes after being put to bed) or frequent night awakenings (woke up more than twice during the night). Of 198?infants, 96?(48.5%) reportedly had sleep disturbances. In the univariate analysis, the factors associated with increased risk of sleep disturbances were (odds ratio, OR; (95%?CI)) first birth order 3.55 (1.90?C6.69), previous abortions 2.08 (1.14?C3.83), maternal vaginal bleedings during pregnancy 2.58 (1.07?C6.29), maternal allergies 2.44 (1.17?C5.14), and maternal smoking during pregnancy 2.45 (1.27?C4.77). Stepwise backward logistic regression analysis identified combinations of the factors that best predicted the risk of infant sleep disturbances: first birth order, previous abortions, and maternal smoking during pregnancy. After inclusion into the multiple logistic regression equation, these factors provided moderate prediction (pseudo R²=0.15). The receiver operating characteristic (ROC) curve was constructed, and the area under the ROC curve was equal to 0.6636 (95%?CI=0.5905?C0.7406), p_(area=0.5)?<0.05. Findings from the maternal history may help to predict sleep disturbances in young infants.     

The effects of maternal risk factors during pregnancy on the onset of sleep difficulties in infants at 3 months old

Sleep problems in young children are among the most common concerns reported to paediatricians. Sleep is thought to have important regulatory functions, and sleep difficulties in early childhood are linked to several psychosocial and physiological problems. Moreover, several prenatal factors have been found to influence infants’ sleep. Among them, most of the studies have been focused on maternal prenatal depression and/or anxiety as potential risk factors for sleep problems in childhood, whereas other relevant psychological factors during pregnancy have not received as much attention. Therefore, we aimed to examine the effect of several psychiatric maternal risk factors during pregnancy (i.e. symptoms of anxiety, depression, insomnia, alcohol use, seasonality, attention deficit and hyperactivity disorder and/or stressful life events) on the onset of some sleep problems related to sleep quality and sleep practices in 3‐month‐old infants. We examined 1,221 cases from a population‐based birth cohort, with subjective measures during pregnancy in mothers, and at 3 months after birth in the infants. The findings showed that all the maternal risk factors during pregnancy, except for symptoms of alcoholism and sleepiness, were related to sleep difficulties in infants. Interestingly, attention deficit and hyperactivity disorder symptomatology in mothers during pregnancy was the only variable that predicted more than two sleeping difficulties (i.e. long sleep‐onset latency, co‐sleeping with parents and irregular sleeping routines) at 3 months old. Our results highlight the relevance of maternal risk factors during pregnancy, and not only prenatal depression and/or anxiety, as variables to be considered when examining sleep difficulties in infants.     

Low parental tolerance for infant crying: an underlying factor in infant sleep problems?

Parenting behaviours play a major role in the evolution of infant sleep. Sleep problems in infancy have been associated with excessive parental involvement at night‐time, and with shorter delays in response to infant night wakings and signalling. Infant crying and sleep problems are linked, yet little is known about the impact of parental responses to crying on infant sleep patterns. This study examined the hypothesis that lower parental tolerance for crying is associated with infant sleep problems. We studied 144 married couples divided into three groups: parents of infants suffering from night‐waking problems (i.e. the clinical group), parents of infants without sleep problems and childless couples. Crying tolerance was assessed using questionnaires, audio recordings of crying infants and using a novel paradigm, in which participants were shown a video of a crying infant and asked when they would intervene. Parents in the clinical group demonstrated shorter intervention delays in the crying infant clip (group effect: P < 0.0001), and tended to attribute more distress to the crying infants compared to parents in both control groups (P < 0.05). Additionally, women demonstrated lower tolerance for infant crying on most measures compared to men. Our results suggest that parents of sleep‐disturbed infants appear to have lower tolerance for infant crying, which may be a predisposition underlying their excessive involvement in soothing their infants to sleep which may lead to the development of sleep problems. These preliminary findings should be explored further to assess their clinical validity and utility.     

Exercise before bed does not impact sleep inertia in young healthy males

Sleep inertia is the transitional state marked by impaired cognitive performance and reduced vigilance upon waking. Exercising before bed may increase the amount of slow‐wave sleep within the sleep period, which has previously been associated with increased sleep inertia. Healthy males (n = 12) spent 3 nights in a sleep laboratory (1‐night washout period between each night) and completed one of the three conditions on each visit – no exercise, aerobic exercise (30 min cycling at 75% heart rate), and resistance exercise (six resistance exercises, three sets of 10 repetitions). The exercise conditions were completed 90 min prior to bed. Sleep was measured using polysomnography. Upon waking, participants completed five test batteries every 15 min, including the Karolinska Sleepiness Scale, a Psychomotor Vigilance Task, and the Spatial Configuration Task. Two separate linear mixed‐effects models were used to assess: (a) the impact of condition; and (b) the amount of slow‐wave sleep, on sleep inertia. There were no significant differences in sleep inertia between conditions, likely as a result of the similar sleep amount, sleep structure and time of awakening between conditions. The amount of slow‐wave sleep impacted fastest 10% reciprocal reaction time on the Psychomotor Vigilance Task only, whereby more slow‐wave sleep improved performance; however, the magnitude of this relationship was small. Results from this study suggest that exercise performed 90 min before bed does not negatively impact on sleep inertia. Future studies should investigate the impact of exercise intensity, duration and timing on sleep and subsequent sleep inertia.     

Worried sleep: 24-h monitoring in high and low worriers

Background

Commonly used trait measures might not accurately capture the relationship between worry and sleep difficulties in real life.

Methods

In a 24-h ambulatory monitoring study, high and low trait worriers maintained a log of worry and sleep characteristics while actigraphy, heart rates (HR), skin conductance (SC), and ambient temperature were recorded.

Results

Worrying in bed on the night of the recording was associated with longer self-reported and actigraphic nocturnal awakenings, lower actigraphic sleep efficiency, higher HR, lower HR variability, elevated SC level, and more non-specific SC fluctuations compared to not worrying in bed. High trait worriers had higher HR during waking and sleep, and reported shorter total sleep time and poorer sleep quality.

Conclusions

While trait worry is mainly associated with subjective sleep difficulties, worrying in bed impairs sleep according to both subjective and objective sleep parameters, including heightened sympathetic and reduced parasympathetic activation.     

Assessing sleep quality using self‐report and actigraphy in PTSD

Sleep disturbance is commonly reported by participants with post‐traumatic stress disorder, but objective evidence of poor sleep is often absent. Here we compared self‐report and actigraphic evaluations of sleep between veterans with post‐traumatic stress disorder and controls. Participants reported their sleep retrospectively for the month before the recording night and on the recording night. On the recording night, they wore an Actiwatch‐64 and were instructed to press the marker button upon getting into bed, each time they awoke, and at their final awakening. The post‐traumatic stress disorder group reported much worse sleep than controls on the Pittsburgh Sleep Quality Index for the previous month and somewhat poorer sleep on the recording night. However, on the recording night, neither diary nor actigraphic measures of number of awakenings, total time in bed, nor time lying awake after sleep onset differed between participants with and without post‐traumatic stress disorder. Diary‐reported number of awakenings was fewer than actigraphically captured awakenings. These results suggest a memory bias towards remembering worse sleep on the nights before the recording night.     

Effects of Immigration on Infant Feeding Practices in an Inner City,Low Socioeconomic Community

ObjectiveInfant feeding practices have been shown to differ between immigrants and non-immigrants in the United States. Our study characterizes feeding practices of infants of immigrant versus American-born mothers followed in an inner city Pediatric continuity clinic serving predominantly low socioeconomic status families.MethodsA survey was given to 102 parents of infants ranging from 12 to 15 months of age who attended the clinic. Parents were asked about their country of origin, ethnic background and time since immigration to the US. They were also asked about their breastfeeding and early infant feeding practices. Statistical significance was estimated using chi-squared tests.ResultsNot only were breastfeeding rates higher among immigrant mothers compared to American-born mothers (88% vs. 63%, p-value 0.008) but they introduced commercially available baby food less frequently (37% vs. 52%, p-value 0.03) and rarely fed their infants fast food (22% vs. 50%, p-value<0.001). Moreover, breast feeding rates decreased with duration of residence in the United States. 53% of immigrant mothers who have been in the United States for less than 5 years breastfed for over 6 months versus 22% of immigrant mothers who resided more than 5 years in the United States (p-value 0.02). The vast majority of immigrant mothers who switched to formula did so because they felt their milk production was insufficient (93%) whereas the vast majority of American-born mothers stopped breastfeeding because they perceived it to be painful (64%, p value 0.001).ConclusionsInfant feeding practices differ between immigrant and American-born mothers and the differences diminish the longer the mothers reside in the United States. These differences stem from differences in cultural perceptions of breastfeeding. Therefore, in educating mothers about infant feeding, physicians should strongly consider cultural and ethnic factors.     

Sleep extension versus nap or coffee,within the context of ‘sleep debt’

Though extended night‐time sleep mostly reduces the ‘afternoon dip’, little is known about evening benefits to alertness, or about comparisons with an afternoon nap or caffeine. Twenty healthy carefully screened adults, normal waking alertness levels, underwent four counterbalanced conditions: usual night sleep; night sleep extended<90 min (usual bed‐time); up to 20 min afternoon nap; and 150 mg afternoon caffeine (versus decaffeinated coffee). Sleepiness was measured by afternoon and evening multiple sleep latency test (MSLTs), longer psychomotor vigilance test (PVT) sessions and a subjective sleepiness scale. Sleep was extended by average of 74 min, and all participants could nap 15–20 min. Sleep extension had little effect on PVT determined modest levels of morning sleepiness. Afternoon and evening MSLTs showed all active treatments significantly reduced the ‘dip’, with nap most effective until mid‐evening; next effective was caffeine, then extension. Late evening sleepiness and subsequent sleep did not differ between conditions. Arguably, participants may have experienced some ‘sleep debt’, given they extended sleep and reflected some sleepiness within settings sensitive to sleepiness. Nevertheless, extended sleep seemed largely superfluous and inefficient in reducing modest levels of sleepiness when compared with a timely nap, and even caffeine. Sleep, such as food and fluid intakes, can be taken to excess of real biological needs, and for many healthy adults, there is a level of modest daytime sleepiness, only unmasked by very sensitive laboratory measures. It may reflect a requirement for more sleep or simply be within the bounds of normal acceptability.     

Chronic sleep curtailment impairs the flexible implementation of task goals in new parents

Chronic sleep curtailment is a major concern for health in Western societies. Yet, research on potential consequences of long‐term sleep curtailment on cognitive functions is still scarce. The present study investigated the link between chronic sleep limitation and executive functions that enable adaptation to changing environmental demands, i.e. the ability to flexibly implement task goals. To address the effects of chronic sleep restriction under real‐life conditions, we considered a sample of adults who often suffer from reduced sleep durations over many months. One‐hundred and six new parents (infant’s age: 6–18 months) were assigned to a sleep‐curtailed group (<7 h of nighttime sleep) and a non‐sleep‐curtailed group (≥ 7 h of nighttime sleep), respectively, based on their self‐reported average nighttime sleep duration over the preceding 6 months. The ability to implement task goals was addressed applying a task‐switching paradigm in which participants randomly switched between two tasks. While the two groups did not differ with regard to overall performance level, number of nighttime awakenings, naps during the day, daytime sleepiness, mood, chronic stress level and subjectively perceived cognitive capability, sleep‐curtailed new parents showed higher costs for switching between tasks compared with repeating a task than non‐sleep‐curtailed new parents. This finding on the group level was further substantiated by a negative correlation between nighttime sleep duration and switch costs. With this study, we provide the first evidence for an impairment of the ability to flexibly implement task goals in chronically sleep‐deprived new parents and, thus, for a link between chronic sleep curtailment and executive functions.     

Subjective–objective sleep discrepancy among older adults: associations with insomnia diagnosis and insomnia treatment

Discrepancy between subjective and objective measures of sleep is associated with insomnia and increasing age. Cognitive behavioural therapy for insomnia improves sleep quality and decreases subjective–objective sleep discrepancy. This study describes differences between older adults with insomnia and controls in sleep discrepancy, and tests the hypothesis that reduced sleep discrepancy following cognitive behavioural therapy for insomnia correlates with the magnitude of symptom improvement reported by older adults with insomnia. Participants were 63 adults >60 years of age with insomnia, and 51 controls. At baseline, participants completed sleep diaries for 7 days while wearing wrist actigraphs. After receiving cognitive behavioural therapy for insomnia, insomnia patients repeated this sleep assessment. Sleep discrepancy variables were calculated by subtracting actigraphic sleep onset latency and wake after sleep onset from respective self‐reported estimates, pre‐ and post‐treatment. Mean level and night‐to‐night variability in sleep discrepancy were investigated. Baseline sleep discrepancies were compared between groups. Pre–post‐treatment changes in Insomnia Severity Index score and sleep discrepancy variables were investigated within older adults with insomnia. Sleep discrepancy was significantly greater and more variable across nights in older adults with insomnia than controls, P ≤ 0.001 for all. Treatment with cognitive behavioural therapy for insomnia was associated with significant reduction in the Insomnia Severity Index score that correlated with changes in mean level and night‐to‐night variability in wake after sleep onset discrepancy, P < 0.001 for all. Study of sleep discrepancy patterns may guide more targeted treatments for late‐life insomnia.     

Development of sleep–wake rhythms during the first year of age

Circadian rhythms refer to biological rhythms that have an endogenous period length of approximately 24 hr. However, not much is known about the variance in the development of the sleep–wake rhythm. The study objectives were (a) to describe the normative variation in the development of a sleep–wake rhythm in infancy, (b) to assess whether slower development is related to sleep quality and (c) to evaluate factors that are related to the slower development of a sleep–wake rhythm. The study is based on a representative birth cohort. Questionnaires at the ages of 3 (n = 1,427) and 8 months (n = 1,302) and actigraph measurement at 8 months (n = 372) were available. Infants with significant developmental delays (n = 11) were excluded. The results are based on statistical testing and multivariate modelling. We found that the average percentage of daytime sleep was 36.3% (standard deviation [SD], 8.5%) at 3 months and 25.6% (SD, 6.6%) at 8 months. At both time‐points, infants with slower sleep–wake rhythm development slept more hours per day, had a later sleep–wake rhythm, more difficulties in settling to sleep and longer sleep‐onset latency; they also spent a longer time awake during the night. According to actigraph registrations, we found that the infants with slow development of a sleep–wake rhythm slept less and had a later start and end to night‐time sleep than the other infants. Infants’ sleep–wake rhythm development is highly variable and is related to parent‐reported and objectively measured sleep quality and quantity. Interventions to improve the sleep–wake rhythm might improve sleep quality in these infants.