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Dummies and sudden infant death syndrome

Alison Wall
BSc SRN SCM HV FPCert
Health Visitor and Public Health Nurse
Watford and Three Rivers PCT

The social history of infant feeding and use of dummies or pacifiers makes fascinating reading. The benefits of an oral soother seem to have been realised centuries ago. Physicians as far back as the 2nd and 4th centuries mention the use of honey during the newborn period for its antimicrobial and antibacterial properties. Teething was seen as a significant problem, and the London Bills of Mortality during the 1600s list teething as a leading cause of infant death.(1) The belief persisted that teething resulted in serious morbidity and death, and in the late 18th century George Armstrong, and later William Buchan, urged the use of bread crusts to combat the effects of teething. Teething rings and bickiepegs have developed from these ideas. Bickiepegs were developed in 1925 by leading paediatrician Dr Harry Campbell. They were designed to be used after six months of age and are still used commonly today. Parents in the 1600s used candy sticks, believing the sugar would soothe and satisfy the baby. Rubber rings of various colours were manufactured during the 1800s. The white rubber actually contained a certain amount of lead. The expression "born with a silver spoon in his mouth" originates from the use of silver dummies by the upper classes. Coral and mother of pearl were also believed to ward off sickness.
At the beginning of the 1900s, however, there was a huge antidummy campaign, when they were viewed as a serious hazard, and their use halved between 1911 and 1930.(2) Diarrhoea was the leading cause of infant death, and dummies were seen as vectors of bacteria and dirt.However, no research found any association between the two. Another explanation may be that dummy use was seen as self-indulgent.(3)
 
Sudden infant death syndrome
Sudden infant death syndrome (SIDS), also known as cot death, can be defined as the sudden death of an infant that was unexpected by clinical factors, and usually affects infants under one year. Despite a significant reduction in the number of babies dying from SIDS, the total number of deaths is still 300 each year. It remains the most common cause of infant mortality.
The Foundation for the Study of Infant Deaths (FSID) has commissioned research looking at possible risk factors for cot death over the years. Many factors have been studied, including such behaviours as coffee consumption, prematurity and maternal smoking. In August 1999 a study of 325 infants who had died from SIDS was carried out, comparing them with 1,300 controls.(4) Fewer SIDS babies had used pacifiers (40%) compared with the control group (51%) for the last sleep. The researcher, however, acknowledged that his findings could be biased from confounding factors - for example, socioeconomic status. He concluded that further epidemiological work needed to be done before dummy use could be recommended as a measure to reduce SIDS risk. Other work carried out in New Zealand,(5) the Netherlands(6) and Norway(7) also reports possible protective effects of dummies. Latterly, US research has really hit the front page with the assertion that use of dummies can reduce the risk by more than 90%.(8) It is important to clarify that the associations found are not causal, as these are only risk factors that are being identified; the cause of sudden infant death remains unknown.
US researchers in California interviewed carers of 185 victims of SIDS, as well as 312 controls. The control group were matched for ethnicity, socioeconomic status and age. They obtained details of dummy use during the "index sleep" - the last sleep before death - and the sleep the night before the interview for the controls. The study, which took place between 1997 and 2000, interestingly linked thumbsucking with a 43% reduction in SIDS risk. The risk, however, was greatest in adverse sleep environments where the baby was co-sleeping - having the baby in bed with the parents, or falling asleep on a settee - lying prone, or with a parent who smoked.
 
How might dummy use offer protection?
Dummies commonly have a bulky external handle that will allow air to freely circulate around the nose and mouth. Regular sucking may also help neural development of the upper airway, and increase arousal responsiveness to a life-threatening challenge, - for instance, a cardiac arrhythmia.
It is also thought that a dummy may prevent oropharyngeal obstruction and retroposition of the tongue. Indeed, the FSID has responded to these claims by saying that if a baby is regularly using a dummy then they should continue to do so.
Two earlier studies have shown that babies who suddenly stop the practice are at increased risk when not using it. They advise that dummies should not be dipped in sweet solutions because of dental and gum disease. The FSID also recommends that a dummy can be removed around the age of one year, and that breastfeeding mothers may like to delay the use of a dummy until four weeks or so while breastfeeding is becoming established.
Other studies have highlighted the potential problems of dummy use. Dummies are thought to delay the development of speech and in particular clear articulation. There is also some evidence that dummy use is linked to an increase in ear infections, pyrexia, colic, wheezing and diarrhoea.(4)
Garth Kendall, a developmental epidemiologist from Australia, believes that parents should avoid the use of dummies unless their child is considered at increased risk of SIDS. His work points to the fact that dummies were associated with a shorter duration of breastfeeding.(9) Others have drawn the same conclusions, while some researchers have found no effect on breastfeeding duration and pacifier use,(10) and parents are to be reminded that breast milk benefits in terms of its immunological and cognitive properties.
Swedish researcher Lennart Righard has published several articles arguing that there is no valid evidence of a link between pacifier use and risk of cot death.(11) He states that recall bias will be a major flaw in the research design, and that prone babies will use a dummy less often than supine purely because of the difficulty of positioning. He claims it is the position of the baby that is significant rather than the fact of whether they are sucking a dummy or not. Japan has one of the lowest rates of SIDS and the lowest rate of dummy use, so there is no evidence in their culture for including dummy use as a protective factor.

What should our advice be?
These latest findings add to the debate about prioritising public health messages. The government has made it clear in the Priorities and Planning Framework(12) that a key target is to increase the initiation rate of breastfeeding by 2%, so that other messages that might impede the success of this may be compromised or given less credence. Evidence recently has shown an association between cot death and co-sleeping. However, the breastfeeding lobby states that it is easier to establish breastfeeding when the baby is close beside the mother and can suck on and off during the night. This creates huge dilemmas for public health and the importance of delivering clear messages that can be easily understood.

Conclusion
In conclusion, it is no surprise that there is hesitation in advocating the use of dummies in child-rearing. The messages remain ambiguous. Could it be that both babies who regularly use dummies and those that never do are at reduced risk of SIDS compared with those who failed to do so in their last sleep? Unfortunately there is no easy answer to this ongoing debate. Public health practitioners need to keep well informed on new research findings in order to be able to discuss the information impartially with clients.
One thing, however, is certain, we have not heard the last of the debate yet.

References

  1. Levin S. A philosophy of infant feeding. Springfield: Charles C Thomas; 1963.
  2. Gale C, Martyn C. Social History of Medicine 1995;8(2):231-55.
  3. Leach P. Your baby and child: from birth to age five. London: Dorling Kindersley; 1997.
  4. Fleming P, et al. Arch Dis Child 1999;81(2):112-6.
  5. Mitchell EA, Taylor BJ, Ford RP, et al. Arch Dis Child 1993;68:501-4.
  6. L'Hoir MP, Engelberts AC, von Well G, et al. Arch Dis Child 1998;79:386-93.
  7. Arnestad M, Anderson M, Rognum T. Eur J Pediatr 1997;156:968-70.
  8. Li D, et al. BMJ 2006;332:18-22.
  9. Victoria CG, et al. Pediatrics 1997;99:445-53.
  10. Schubiger G, et al. Eur J Pediatr 1997;156:874-7.
  11. Righard L.Birth 1998;25(2):128-9.
  12. DH. Priorities and planning framework. London: HMSO; 2002.