The Journal of Pediatrics
Volume 155, Issue 4 , Pages 461-462, October 2009

Does Swaddling Decrease or Increase the Risk for Sudden Infant Death Syndrome?

  • Bradley T. Thach, MD

      Affiliations

    • Corresponding Author InformationReprint requests: Bradley Thach, MD, Washington University School of Medicine, 660 South Euclid, Campus Box 8208, St Louis, MO 63110.

Department of Pediatrics, Washington University, St. Louis, Missouri

Article Outline

SIDS, Sudden infant death syndrome

 

See related article, p 475

The report by Richardson et al in this issue of The Journal adds to their extensive past studies on arousal from sleep in infants.1 This report on arousal in swaddled infants is an important addition to the literature. As the authors indicate, swaddling is becoming an increasingly common practice in the US. Historically, swaddling was for the most part a universal practice before the eighteenth century. The article is unique in that it reports on arousal to a tactile stimulus as opposed to spontaneous arousal.

Richardson et al address several important issues. First, is a low threshold for arousal necessarily a good thing? This may not be the case, because cortical arousals may be disadvantageous in certain situations.2 Cortical arousal in infants is often accompanied by hypoventilation, especially with crying, which can precipitate sudden, severe oxygen desaturation in an infant in an asphyxial rebreathing environment. In some cases, this may precipitate sudden unexpected death.3 Moreover, frequent arousals caused by a low arousal threshold might result in habituation and thereby increase the theshold for arousal, which would be disadvantageous in asphyxia-induced arousals. Fortunately, in the present study, as noted previously, swaddling did not appear to impair subcortical arousals, which are essential for adequate pulmonary function and appear to be the primary mechanism in terminating obstructive apnea in infants.2, 4

Does the tactile stimulus used by Richardson et al adequately reflect the arousal caused by asphyxia? This question is highly relevant, because asphyxia and/or hypoxia is widely believed to be the major preceding event leading to sudden infant death syndrome (SIDS). How closely arousal to a tactile stimulus is correlated with arousal caused by asphyxial stimuli remains unclear. Certainly cortical arousal is needed to escape from a life-threatening asphyxiating environment, either through a change in head position or when crying alerts a caretaker to a dangerous situation. Equally relevant is the fact that cortical arousal does not appear to be necessary for terminating central or mixed apnea in infants.5, 6, 7 Thus, impairment of cortical arousal associated with swaddling might not be a disadvantage in terminating these types of apnea.

Can swaddling actually increase the risk for SIDS, as the authors suggest? This is certainly true for prone-sleeping infants.8 In this case, head-lifting and turning to avoid an asphyxial environment are impeded when the arms are restrained at the infant's side rather than positioned beside his or her head. In contrast, the mechanisms of swaddling's affect on decreasing the risk of SIDS in supine-sleeping infants seem clear. An immobilized infant cannot crawl into a dangerous asphyxiating environment. Also, swaddling prevents an infant from pulling bedding over his or her head. Both of these are risk factors for accidental suffocation and/or SIDS. The only evidence of an increased risk of SIDS in swaddled infants comes from a non–peer-reviewed abstract.9 Significantly, however, that study did not distinguish between infants swaddled in the prone position and those swaddled while supine. As indicated earlier, prone-swaddled infants are at greatly increased risk for SIDS.8 Particularly relevant here is that 2 previous studies have found that swaddling actually reduces the risk of SIDS when infants sleep in the supine position.8, 10

The potential dangers of swaddling infants should not be entirely dismissed, however. The authors have confirmed previous studies indicating that swaddling is associated with increased respiratory rate.11, 12 As the authors surmise, this is likely due to a decreased functional residual capacity resulting from increased extrathoracic pressure. In theory, decreased functional residual capacity might be deleterious in certain situations where pulmonary function is compromised, as in the case of viral pneumonia. Moreover, cough might be expected to be compromised, because forceful coughing must be preceded by inhalation, which increases lung volume. Notably, a popular publication that gives advice to parents has stated that the tighter the swaddling, the greater the calming effects on infants.13 Taking all of these factors into account, caretakers need some simple method to determine thoracic pressure in swaddled infants to ensure that the thoracic pressure imposed does not compromise lung function while still providing swaddling's calming effects.

In summary, the article by Richardson et al adds significant new information on arousal thresholds to tactile stimuli in swaddled infants. It should be noted, however, that currently there is insufficient evidence to indicate that infants swaddled while supine are at increased risk for SIDS. All in all, it would appear that the advantages of swaddling supine-sleeping infants outweigh the risks, if any.

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References 

  1. Richardson HL, Walker AM, Horne RSC. Minimizing the risks of sudden infant death syndrome: to swaddle or not to swaddle?. J Pediatr. 2009;155:475–481
  2. Thach BT. Sleep, sleep position, and the sudden infant death syndrome. To sleep or not to sleep? That is the question. J Pediatr. 2001;138:793–795
  3. Thach BT, Harris KA, Krous HF. The potential role of pulmonary arteriolar medial smooth muscle thickening in the sudden unclassified death of a young infant. BMJ. 2009;
  4. Wulbrand H, McNamara F, Thach BT. The role of arousal related brainstem reflexes in causing recovery from upper airway occlusion in infants. Sleep. 2008;31:833–840
  5. Thoppil CK, Belan MA, Cowen CP, Mathew OP. Behavioral arousal in newborn infants and its association with termination of apnea. J Appl Physiol. 1991;70:2479–2484
  6. Davies AM, Koenig JS, Thach BT. Characteristics of upper airway chemoreflex prolonged apnea in human infants. Am Rev Resp Dis. 1989;139:668–673
  7. Garrick WD, Waters KA. Influence of sleep state on frequency of swallowing, apnea, and arousal in human infants. J Appl Physiol. 2003;94:2456–2464
  8. Ponsonby AL, Dwyer T, Gibbons LE, Cochrane JA, Wang YG. Factors potentiating the risk of sudden infant death syndrome associated with the prone position. N Engl J Med. 1993;329:377–382
  9. Fleming P. Research and current advice: an overview. Presented at the SIDS 10th International Conference, Portsmouth, UK, 2008.
  10. Wilson CA, Taylor BJ, Laing RM, Williams SM, Mitchell EA. Clothing and bedding and its relevance to sudden infant death syndrome: further results from the New Zealand Cot Death Study. J Paediatr Child Health. 1994;30:506–512
  11. Gerard CM, Harris KA, Thach BTT. Physiologic studies in swaddling: an ancient childcare practice, which may promote the supine for infant sleep. J Pediatr. 2002;141:398–404
  12. Narangerel G, Pollock J, Manaseki-Holland S, Henderson J. The effects of swaddling on oxygen saturation and respiratory rate of healthy infants in Mongolia. Acta Paediatr. 2007;96:261–265
  13. Karp H. The Happiest Baby on the Block. New York: Bantam; 2002;

 Supported by National Institute of Child Health and Human Development Grant HD-10993.

PII: S0022-3476(09)00556-3

doi:10.1016/j.jpeds.2009.06.011

Refers to article:

  • Minimizing the Risks of Sudden Infant Death Syndrome: To Swaddle or Not to Swaddle? , 22 June 2009

    Heidi L. Richardson, Adrian M. Walker, Rosemary S.C. Horne
    The Journal of Pediatrics October 2009 (Vol. 155, Issue 4, Pages 475-481)

The Journal of Pediatrics
Volume 155, Issue 4 , Pages 461-462, October 2009

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