Table 5 Studies exploring aspects associated with infant sleep quality (Alphabetic ordered after first author)

22.

Adams et al. (2020) [60]

USA

Investigation of how early or later bedtimes may influence night-time sleep duration in 2–24 weeks old infants.

N = 24 newborns

Study with microburst longitudinal design, assessing infant sleep with actigraphy and maternal reports at infants ages 6, 15 and 24 weeks.

For every 1 hour earlier in infants’ usual sleep night-time onset (SNTO) total night-time sleep (TNTS) 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).

Bedtime routines; sleep duration.

This study demonstrate that earlier bedtimes may benefit sleep among the youngest infants in addition to early consistent bedtime routines.

23.

Bennett et al. (2013) [61]

United Kingdom

Review of how massage may promote sleep habits among healthy term-born infants aging 6 month or less.

Cochrane review of studies published before June 2011. Inclusion of 34 RCTs.

Heterogeneity between included studies were substantial and massage was only modestly associated with positive effects on 24-hour sleep duration.

Parent behavior (babymassage); sleep quality

No studies documented negative effects of massage for this population

24

Bilgin & Wolke (2020) [62]

United Kingdom

Observation of associations between parental use of “cry it out” and childrens attachment quality and crying behavior at 18 months. N = 178 parent-infant dyads.

Prospective, longitudinal study recruiting families across 3 maternity wards.

Parents reported use of “cry it out” at term and when infants were 3, 6 and 18 months.

No adverse impacts of leaving infants to “cry it out” was detected in the first 6 months of life. Tested in relation to infants’ attachment quality and cry-frequency at 18 months.

Often use of “cry it out” was reported by 8–13% at term-age, 3 and 6 months. Never use of this strategy were reported by 63% at term-age and from about 40% of families at 3 and 6 months.

Parent behavior and infant crying.

Leaving infants to “cry it out” at term, both a few times and often, was negatively associated with frequency of crying at 3 months.

The authors neither recommend leaving infant to cry out nor responding immediately. The findings are thought to be consistent with an approach to parenting that is intuitive and adapts to infants demands and regulatory behaviors.

25.

Bruni et al. (2014) [63]

Italy

A longitudinal examination of sleep patterns, habits and parent-reported sleep problems among infant aging 1 to 12 months.

N = 704 infants assessed by 81 different Italian pediatricians.

Prospective, longitudinal cohort study collecting data on sleep outcomes from parents answering surveys by telephone interviews. 3520 surveys were collected.

Both night-time, daytime and total sleep duration showed high inter-individual variability from one to 12 months associated with changes the first six months and stability after that

Sleep quality; sleep duration

Investigates sleep arrangements and sleep challenges. Provides a context for clinicians to discuss sleep issues with parents and suggest that prevention efforts should focus to the first 3–6 months, since sleep patterns show stability from that time point to 12 months.

26.

Chen et al. (2019) [64]

Singapore & Germany

An investigation of associations between screen viewing (SV) and sleep duration among children less than 2 years old.

N = 714 infants.

Cross-sectional study using parental reports of SV and sleep.

For the whole sample was 1 hour SV associated with 16 minutes shorter TST (p < 0.001). The prevalence of daily SV among infants 0 to 6 month was 28.3% and their mean screen time was 60 minutes (IQ range 0.44 to 120) Compared to the no-screen group a dose-response relation was detected for young screen-viewers.

Screen viewing; sleep duration

The negative association between SV and sleep duration was strongest among the youngest infants.

27.

Field et al. (2016) [65]

USA

An investigation of differences between baby massage with lotion (LM-group) or without lotion (non-LM group) or no massage at all (control group) and whether this influences infant sleep quality. N = 76 mother-infant dyads.

RCT, program started in the post-delivery ward and was evaluated at a 1-month follow-up.

Use of maternal self-report.

Compared to the other groups, shorter sleep latency was found in the LM-group (p = 0.002), and decreased number of nightwakings (p = 0.008). LM-mothers reported higher confidence in managing their infants sleep (p = 0.03). There was a positive correlation between the number of massages and longer infant night-time sleep (p < 0.005).

Parent behavior (babymassage)

Infant and maternal sleep was highly correlated. Massage without lotion might be uncomfortable for newborns and new parents need to get knowledge about this factor and the dose-dependent association between baby massage and night-time sleep. Maternal ratings of infant sleep difficulties tended to decrease in the LM-group compared to the non-LM group.

28.

Fiese et al. (2021) [14]

USA

An investigation of associations between bedtime routines and infant sleep quality in infancy. N = Parent of 468 infants.

Part of a large prospective, longitudinal cohort study. Bedtime routines and sleep measures were reported by mothers on questionnaires at infants ages of 3,12,18 and 24 months.

More bedtime routine consistency predicted less night-time waking and sleep problems across infancy. More adaptive activities at 3 months of age predicted longer sleep duration at 12 months (r = 0.12, p < 0.05).

Bedtime routines; sleep quality

Bedtime routines and sleep outcomes had moderate stability over time, especially from one to two years.

29.

Kahn et al. (2021) [66]

USA

An examination of the moderating role of infant age on the relation between infants’ use of different screens and sleep outcomes. N = 1074 infants aged 0–18 months.

Cross-sectional study.

Data collection by parental reports and autovideosomnography.

Age moderated the relation between daytime touchscreen exposure and sleep. For 3- months old infants were a 5-minute daytime touchscreen exposure associated with an average decrease of 13 minutes daytime sleep (b = − 2.62, SE = 0.62, p < 0.001. More daytime touchscreen exposure was associated with fewer awaking’s (b = − 0.03, SE = 0.01, p = 0.03)

Screen viewing; sleep duration

The author suggests that displacement of daytime sleep by screens may lead for a greater accumulation of sleep homeostatic pressure, possibly facilitating more consolidated night-time sleep among the youngest infants.

30.

Lennartsson et al. (2016) [67]

Sweden

An evaluation of a child health nurses educational program aiming to improve their ability to talk with new parents about risks of cranial asymmetry in newborns and how to prevent this the first 4 month after birth. N = 272 parents

A cross-sectional survey nested in a larger intervention study.

Data collection by parental report on questionnaires at children’s age of 4 month.

Parent in the education-group reported more often that they were aware of the importance of alternating the direction of their infant’s head when initiating sleeping compared to control-group parents (82% versus 64%, p = 0.001). Significant group differences were also found in relation to which kind of pillows that could be used and when they should be removed.

Parent behavior; Infant physical health

The paper gives detailed information about the advice nurses should give and it seems relevant to integrate this in talks about infant sleep issues.

31.

Meyer et al. (2011) [68]

Germany

A comparison of sleep among healthy infants. A swaddling group (SG = 40) and a control group using sleeping bags (CG = 45) were compared. N = 85 infants.

Prospective, observational study with use of polysomnography to assess differences in sleep stages and awaking’s in 7.5 weeks old infants.

Compared to use of sleeping bags swaddling reduced the rate of spontaneous waking (p = 0.020), reduced the number of changes in sleep state (p = 0.015), promoted more quiet sleep (p = 0.032), and reduced time spent awake (p = 0.001). Sleep efficiency was increased (p = 0.001).

Parent behavior (swaddling); sleep quality

The authors conclude that swaddling may reduce the risk of infant injuries or death as sleep becomes more consolidated even when children sleep in the recommended supine position.

32.

Mindell et al. (2015) [69]

USA

Investigates if there are dose-dependent associations between use of bedtime routines and healthy sleep habits. N = 10,085 mothers from 14 countries.

Multinational cross-sectional study using the Brief Infant /Child Sleep Questionnaire (BICQ) in all countries.

Consistent bedtime routines (CBR = 3–7 times per week) among preschoolers were associated with more routines in infancy. A dose-dependent association between CBR and better sleep outcomes were documented for infants, toddlers and preschoolers.

Bedtime routines

Routines that are instituted in early infancy are associated with better sleep outcomes later in childhood.

33.

Mindell et al. (2018) [70]

USA

A study examining the impact of a consistent bedtime routine involving massage on infants and mothers sleep and mood.

N = 123

Prospective study randomizing families with 3–18 old infants to an intervention (IG, n = 64) or a control group (CG, n = 59). Data collected by maternal self-report.

After one and two weeks no changes were detected among CG-infants while night-waking decreased among IG-infants at both times (F = 5.36, p = 0.006). Fewer IG-mother reported their infant with a sleep problem at these times (p = 0.013) and they were more confident with their ability to manage infant sleep compared to CG-mothers (F = 8.42, p < 0.001).

Bedtime routines

Participating families were not identified with any sleep problems before study inclusion. Mean age of the children were almost 9 months. The intervention did not affect any other maternal outcome than fewer night-waking.

34

Oden et al. (2012) [71]

USA

Investigates the associations between parent’s use of swaddling and infant sleep positions. N = 103 parents

Cross-sectional descriptive study recruiting parents to answer a survey at well child visits with infants aged 0–3 months.

All parents had sometimes swaddled their infant and parents who used swaddling routinely were more likely to but their infant in supine position when swaddled (p < 0.01).

Parent behavior (swaddling)

Most parents found swaddling as a safe practice. Parents who not swaddled routinely were more likely to use inappropriate sleeping positions. Parents need to learn how to swaddle in a safe manner to avoid increased risks of injuries or sudden death.

35.

Paul et al. (2017) [72]

USA

This study investigates associations between parent-infant room sharing and sleep outcomes.

N = 230 mother/infant dyads with healthy, term born infants at a US maternity ward.

A randomized controlled trial collecting data by maternal self-report. Mothers reported on Brief Infant Sleep Questionnaire, BISQ) at children’s age of 4 and 8 months

By 4 months: children sleeping in separate rooms had more regular bedtime routines adjusted OR 1.93 (95% CI:1.05–3.53,), p = 0.03, they were put to bed earlier adjusted OR 1.93 (95% CI: 1.06–3.53), p = 0.03. They were also reported with longer sleep laps (29 min.) than room sharers (p = 0.02), fewer feedings at night (p = 0.02), safer sleep environment (p = 0.02) and less frequent moved over to parents’ bed at night adjusted OR = 0.24 (95% CI: 0.09–0.61), p = 0.003

Sleep location; sleep quality

This research is one part of a large comprehensive study that primarily focuses on obesity prevention.

36.

Philbrook & Teti (2016) [73]

USA

Investigates associations between night-time parenting behavior and infants’ cortisol patterns at 3,6 and 9 months.

N = 82 mother-infant dyads.

Prospective, observational study collecting data by use of video equipment in family homes, salvia sampling and maternal self-report.

Multilevel modeling revealed that infant cortisol levels were lower at timepoints when mothers were scored as emotionally available (b = −.25, p < 0.01). This association was driven by lower infant cortisol levels at bedtime (b = −.35, p < 0.01).

Bedtime routines; parental emotional availability

Findings shed light on factors involved in transactional relationships between infants and parents, relevant in relation to stress regulation and the importance of biobehavioral synchrony.

Cortisol decreased with age for infants of less emotional available mothers but remained at low levels for infants of more emotionally available mothers.

37.

Voltaire & Teti (2018) [74]

USA

An investigation of associations between different sleep arrangements (cosleepers or not) and two different night-time behaviors among parents (using distress-initiated or non-distress-initiated strategies). N = 107 families

Prospective observational study (part of the large SIESTA-study). Families were recruited in the maternity ward and data collected at children’s age of 1,3,6 and 9 month using observations and questionnaires

The number of distress-initiated parent-infant episodes at night in the first 3 months affected the decline in nightwakings. More of these episodes were associated with a steeper decline in night waking. For infants that mostly were solitary sleepers more non-distressed episodes were associated with slower decrease in number of night-waking with age and low levels of non-distressed episodes were associated with faster reduction of night waking.

Parenting behavior; physical health; sleep quality

It is suggested that infant sleep regulation may benefit from appropriate night-time interventions in the 3 first month of life, while similar association not were detected at six months.

Maternal responsiveness during the first few months of life is associated with lower levels of infant distress toward the end of the first year.

38.

Östürk & Temel (2019) [75]

Turkey

A 90-minute training program focusing on appropriate soothing techniques for newborns were introduced to an intervention group (IG = 21) at a home visit 4 weeks after given birth and compared with families forming a control group (CG = 21).

N = 42 mother-infant dyads.

A single-blind randomized experimental study comparing IG and CG parents reports of infant’s self-regulation when infants were 3,7,11 and 23 weeks old.

No group differences were found before the program was introduced to the IG group. At 7 weeks IG-infants slept more than CG-infant (on average 78 min per 24 h, p = 0.004), woke up more seldom (p = 0.001) and cried less (p = 0.001) and fed more seldom per 24 h (p = 0.001). Similar group differences were detected at infants age of 11 weeks, and for most variables, but not for sleep duration at 23 weeks.

Parent behavior (soothing techniques); sleep quality

Helping new parents to understand how they can support infants to establish best possible regulative behavior across the first weeks and month of life seem.

The techniques used in this study were swaddling, holding an unsettled infant in side- or prone position, use sushing with white noise and swing the infant vertically.