For my blog today, I am following up my Thursday Night Live on Newborn Sleep by sharing a review of infant sleep research I wrote a couple of years ago, as it brings together so much of the evidence to dispel so many of the myths and expectations that lead new and sleep deprived mothers to seek quick fix solutions to perceived sleep problems which are often just biological norms for infants, or the result of infant development leaps. IT may be a bit of a heavy read for some, but it’s not that long, and all of the references are linked below. The key ones I would refer parents to jump over to are The Baby Sleep Information Service and The Lullaby Trust..

Infant Sleep Patterns and Cycles

Newborn up to 3 months tend to sleep twice as much as adults- up to 18 hours in every 24. However, that sleep is split over the 24 hour window, and into shorter bursts and cycles of 2-3 hours at a time. However, as ISIS explains, over the first 12 months, this sleep requirement reduces down to about- 15 hours a day, but with the majority of this falling into ‘night time hours’ as a baby’s circadian rhythm begins to develop. (ISIS online 2018). They go on to explain that “Night-waking is normal during early infancy and healthy babies experience several awakenings per night at the end of sleep cycles.” Below is a graph displaying the ‘range of normal’ for average sleep hours of infants 0-12 months taken from a systematic review of 34 studies into infant sleep patterns (Galland et al. 2012) . St James-Roberts et al. (2015) showed that although sleep periods lengthen with age, infants continue to wake up during the night for the first year of life.

Babies have a sleep cycle of around 60 minutes, unlike adults of around 90. Unlike an adult’s sleep cycle, babies they spend the majority of their sleep time in REM/Active sleep rather than deep restful sleep, meaning that they are easily disturbed and naturally start to move into a lighter sleep again after 45 minutes. St James-Roberts et al (2015) research also showed that babies often wake and resettle themselves without parental awareness (25% of 5 week-3 month olds), but at other times require feeding or resettling support.

Feeding and Sleeping

It is to be expected that a young infant will wake frequently during the night for milk feeds, as their stomachs are very small and can only hold a small amount of milk each feed However, as they grow from 3 months onwards, babies may begin to skip a feed during the night giving them a 5 hour stretch of sleep. From 5 months old, they may drop another night feed and have one 7-8 hours stretch of sleep during the night. (ISIS 2018) Day time naps will gradually become shorter and night time sleep longer over the following few months.

Rumours of babies that sleep 12 hours a night from a very early age are likely to be myth, as small babies need to feed little and often, both day and night, to get their nutritional requirements (Anuntaseree et al. 2007; Barnard 1999). Rumours that bottle fed babies sleep more than breastfed babies is also a myth, dispelled in research by Yoshida et al. (2015).  However research shows that although breastfed infants wake more often, they get better quality sleep (due to melatonin passed in breast milk and reduced instances of colic) and have a reduced risk of SIDS compared to formula fed infants (Lullaby Trust 2018). Formula feeding has been shown to make infants sleep more deeply (Horne et al 2004) and so are harder to arouse, “giving a increased risk of SIDS in arousal-deficient infants”(ISIS 2018)).

Parents say they are keen to get ‘their baby to sleep more’, but actually it is a desire to get them to sleep more during the night, so that they can get more rest also. It is interesting that the research actually shows that breastfeeding mothers, although waking more often, get overall the same amount or more sleep than formula feeding mothers (Montgomery-Downs et al. 2010, Doan et al 2014). I presume this is down to the time it takes to make a bottle, feed, wind and resettle. However, contrary to these studies, more recent research by Rudzik and Ball (2016) found that “popular wisdom in the UK tightly links breastfeeding and inadequate night-time sleep [for Mothers].” However, from 6 months on, Brown and Harries (2015) study reported no difference of night waking or night feeds between mothers who were currently breast or formula feeding infants. “Infants receiving more milk or food during the day were less likely to feed at night, but not less likely to wake.”

Perceptions and Myths

Perception still has a significant part to play in what we, as mothers in our society, feel is acceptable. In Rudzik & Ball’s 2016 study, breastfeeding mothers expressed views of the more fragmented sleep (also supported in a study by Tikotzy et al 2009) being a natural expectation, whilst formula feeding mothers ‘felt it was a problem to be fixed.’ 

This leads on to considering the ‘sleep fixing’ problem solvers/devices/equipment and methods marketed and sold to parents today. Some of these devices are harmless, and if they provide comfort to your baby then that is wonderful. Products, for example, that emit white noise or mimic mothers heart beat or mobile phone apps. There are also specialist swaddling products which, as long as they are made from a light weight breathable material, and do not swaddle the hips, are fine to explore also. However, the Lullaby Trust rightly raises concern over sleep positioners, pillows and ‘nests’ which have stuffed surfaces against which a baby could suffocate (Lullaby Trust 2018).

Sleep experts with published books on techniques ranging from cry it out, controlled crying, camping out, routines, scheduled waking for feeds etc have all capture the minds of sleep deprived parents now and in years gone by. However the less well know evidence-based organisations such as BASIS have a clear review of the evidence on their website and discuss how “Of the 43 articles Douglas and Hill reviewed [in 2013], behavioural sleep interventions in the first 6 months of life did not improve outcomes for mothers or infants and risked unintended outcomes. These include increased amounts of problem crying, premature cessation of breastfeeding, worsened maternal anxiety, and, if the infant is required to sleep either day or night in a room separate from the caregiver, an increased risk of SIDS.”

However education around what is ‘normal’ is far more valuable, alongside support for parents to slowly work with their babies natural rhythms and changes over the first 18 months, introducing bedtime and sleep routines, until they sleep more regularly at night without the need for constant resettling. However, once a child presents with a genuine ‘sleep problem’ it can be harder to differentiate the evidenced based help from the ‘self styled trainers’. Even reviewing recent research into sleep training techniques, ISIS highlights the complicated nature of producing valid results. To draw conclusions from (ISIS 2018- Limitations of Sleep Training Research), many sleep training techniques rely on psychology to retrain infant expressions of their needs. What detriment this may have on infant’s emotional and psychological development we do not know. However, “extinction methods require mother and infant to decouple infant crying from consistent parental response; severing a link (Parsons et al 2010; Feldman 2012; Blunden et al 2011) that is physically and psychologically evolved to ensure infants' survival.” (ISIS 2018). This goes against all we have learned through Ainsworth (1973) and Bowlby (1969) about nurturing strong infant attachment, and so is not something that I would recommend.

An important part of my job is setting parents expectations around sleeping and waking as it is very important. I can be a big area of stress when their expectations do not align to the reality of life with a small baby. For example, Hughes et al (2015) found that parents who perceive their infants’ sleep to be problematic, were more likely to experience stress or depressive symptoms and have poorer self-reported health. Rudzick and Ball (2016) conclude that “there will likely always be trade-offs by which mothers strive to balance infant and self-care”, which I agree.

However supporting them to understand and set their expectations around infant sleep, and to know what to try if improvements in sleep are being sought (eg comforting techniques, white noise, bedtime routines), and what myths and presumptions to avoid (eg stopping breastfeeding as baby will sleep more with formula milk), is an important part of my role offering evidence based support and education for new mothers.

References

• · Anuntaseree, W., Mo-suwan, L., Vasiknanonte, P., Kuasirikul, S., Ma-a lee, A. and Choprapawan C. (2007). "Night waking in Thai infants at 3 months of age: Association between parental practices and infant sleep." Sleep Medicine. 9(5): 564-571

• Barnard, K. E. (1999). Beginning rhythms: The emerging process of sleep wake behaviours and self-regulation. NCAST, University of Washington

• Blunden, S.L., Thompson, K.R. and Dawson, D. (2011). "Behavioural sleep treatments and night time crying in infants: Challenging the status quo." Sleep Medicine Reviews 15(5): 327-334

• Brown, A. and Harries, V. (2015). ‘Infant Sleep and Night Feeding Patterns During Later Infancy: Association with Breastfeeding Frequency, Daytime Complementary Food Intake, and Infant Weight’. Breastfeeding Medicine 10(5):252-258

• Doan, T., Gay, CL., Kennedy, HP., Newman, J. and Lee, KA. 2014. ‘Nighttime Breastfeeding Behavior Is Associated with More Nocturnal Sleep among First-Time Mothers at One Month Postpartum’. Journal of Clinical Sleep Medicine, 10(3):313-319

• Douglas, PS., Hill, PS. 2013. ‘Behavioral Sleep Interventions in the First Six Months of Life Do not Improve Outcomes for Mothers or Infants: A Systematic Review’. J Dev Behav Pediatr 34:497–507

• Galland et al. (2012). Normal sleep patterns in infants and children: A systematic review of observational studies. Sleep Med Rev, 16(3): 213-222

• Rudzick and Ball (2016) Exploring Maternal Perceptions of Infant Sleep and Feeding Method Among Mothers in the United Kingdom: A Qualitative Focus Group Study. Matern Child Health J. 2016 Jan;20(1):33-40. Accessed Online 12/11/18
  https://www.ncbi.nlm.nih.gov/pubmed/26156828

• Baby Sleep Information Source (BASIS) Online (2018) Healthcare Professionals.
  Accessed Online 12/11/18 https://www.basisonline.org.uk/

• Hughes, A. & Gallagher, S. (2015) A Cluster Analysis of Reported Sleeping Patterns of 9-Month Old Infants and the Association with Maternal Health: Results from a Population Based Cohort Study  Matern Child Health J 19:1881–1889

• Parsons, C.E., Young, K.S., Murray, L., Stein, A. and Kringelbach, M.L. (2010) "The functional neuroanatomy of the evolving parent-infant relationship." Progress in Neurobiology 91: 220-241

• Feldman, R. (2012). "Parent-Infant Synchrony: A biobehavioural model of mutual influences in the formation of affiliative bonds." Monographs of the society for research in child development 77(2): 42-51

• Galland, B,C. Taylor, B.K., Elder, D.E and Herbison, P. 2012. ‘Normal sleep patterns in infants and children: a systematic review of observational studies’. Sleep Med Rev, 16(3): 213-222

• Horne, R.S.C., Parslow, P.M., Ferens, D., Watts, A.M. and Adamson, T.M. (2004). "Comparison of Evoked Arousability in Breast and Formula Fed Infants." Archives of Disease in Childhood 89: 22-25

• The Lullaby Trust Online (2018) Evidence Based Advice on Choosing Baby Sleep Products. Accessed Online 12/11/18 https://www.lullabytrust.org.uk/safer-sleep-advice/sleeping-products

• Montgomery-Downs, H.E., Clawges, H.M. and Santy, E.E. (2010). "Infant Feeding Methods and Maternal Sleep and Daytime Functioning." Pediatrics 126(6): e1562-e1568.

• St James-Roberts, I., Roberts, M., Hovish, K. and Owen, C. 2015. ‘Video evidence that London infants can resettle themselves back to sleep after waking in the night, as well as sleep for longer periods, by 3 months of age’.Journal of Developmental & Behavioral Pediatrics, 36 (5):324-329.

• Tikotzky, L., De Marcas, G., Har-Toov, J., Dollberg, S., Bar-Haim, Y. and Sadeh, A. (2010). "Sleep and physical growth in infants during the first 6 months." Journal of Sleep Research 19

• Yoshida, M., Shinohara, H. and Kodama, H. 2015. ‘Assessment of nocturnal sleep architecture by actigraphy and one-channel electroencephalography in early infancy’. Early Human Development 91:519–526.