Ask The Armadillo - Do pacifiers reduce SIDS for breastfed babies?

Q.  I have heard it mentioned anecdotally and in some posts on websites that the research publicised by FSID recommending dummy use to prevent SIDS was sponsored by a dummy manufacturer.  When I have had a quick search around, I haven't been able to find any direct evidence of this; can you shed any further light?
Thanks
Amy
Q.  My health visitor has advised me to give my 3 month old (breastfed infant) a pacifier to reduce the risk of SIDS, do you agree with this?
Jane

A. Hi Amy & Jane, thought I would kill two birds with one stone on this one!  My comments only pertain to the exclusively breastfed baby.

The Science:
Firstly funding - yes certainly an interesting one.  June 2007 FSID announced that putting baby down to sleep with a pacifier reduced the risk of SIDS, they announced this was a promotion in association with MAM pacifiers.  Their balance sheet shows a v large "donation" from MAM - so I guess everyone can make their own judgement on the ethics of that one...

FSID quoted two studies as the basis for this claim, in their recommendation no definition was made between exclusively breastfed infants, or those mix fed/ fully substitute fed.  One study was a meta analysis from 2005, which starts off with very impressive sounding figures, but because so many didn't meet their criteria ultimately states:

Results. Seven studies were included in the meta analysis

So of course I had to dig out the 7 studies....

1. Dummy use, thumb sucking, mouth breathing and cot death - 1999.
In that study there were 73 cases of SIDS,  7 of which were exclusively breastfed for more than 13 weeks - none of the known risk factors were adjusted for eg was baby bedsharing with a smoker, on a soft suface, placed prone in a cot etc

Exclusive breastfeeding for more than 6 and more than 13 weeks appeared to decrease the risk of cot death, but statistical significance was not obtained.

It is important to study whether it is not having a dummy that is risk increasing or whether it is being used to a dummy but then being denies it that puts the baby at risk.

A dummy might also offer protection in breast-fed babies, but since these were under-represented in our group and the effect on breast feeding is unclear, no conclusions can be drawn yet.

Conclusion: We recommend dummy use at least for bottle-fed infants.

In response to the study, Schald and Poets felt the study method was flawed:

There is unequiovocal agreement amongst leadin epidemiologists that the use of statistical tests is in fact inappropriate to assess confounding.  One factor that could be particularly important as a confounder in the study is birth order.  The authors indicate that there was a negative association between pacifier use and birth order of the child.  Since in many studies birth order in itself has turned out to be a risk factor for SIDS, it may be some source of major confounding in their data. (Eur J Paediatrics 2000 159:542-544)

2.  Sudden unexplained infant death in 20 regions in Europe: case control study
This study doesn't adjust at all for feeding method, no distinction was made between breast or substitute fed.

Dummy ever used was correlated with dummy used in last sleep. When these variables were combined, it emerged that it was only when the dummy was used and used for the last sleep that the adjusted OR was significantly less than 1.

3. Environment of infants during sleep and risk of the sudden infant death syndrome

There was no difference in the proportion of the babies who died and controls who routinely used a dummy, but for the last or reference sleep there was a significant excess of control infants (52.8%) who used a dummy compared with babies who died.

 These findings should not be used to claim that dummies prevent cot death, but it may not be appropriate for health care professionals routinely to discourage the use of dummies in young infants

Table 5 shows that in the univariate model there was a significant risk associated with usually using a pacifier but not doing so for the last/reference sleep.

4. Sleep Environment and the Risk of Sudden Infant Death Syndrome in an Urban Population:

Decreased risk of SIDS was found with pacifier use during last sleep and with breastfeeding for any length of time

Parents who already use pacifiers for their infants and those who are not breastfeeding need not be discouraged from using them

5.  Factors relating to the infant’s last sleep environment in sudden infant death syndrome in the Republic of Ireland.
No distinction made between breast and non breastfed.

The prone sleeping position remains a significant SIDS risk factor, and among infants using soothers, the absence of soother use during the last sleep period also significantly increased the SIDS risk.

6.  Dummies and the sudden infant death syndrome 1993

 Use of a dummy in the last sleep for cases of SIDS or in the nominated sleep for controls was significantly less in cases than controls (OR 0.44, 95% CI 0.26 to 0.73). The OR changed very little after controlling for a wide range of potential confounders. It is concluded that dummy use may protect against SIDS, but this observation needs to be repeated before dummies can be recommended for this purpose.

7.  Mattresses, microenvironments, and multivariate analyses
As the title suggests, this article focusses on mattresses and doesn't mention either pacifiers or breastfeeding.

The second study FSID quoted is: "Use of a dummy (pacifier) during sleep and risk of sudden infant death syndrome (SIDS): population based case-control study"
Again feeding method was not examined at all in this paper and the focus is dummy used for last sleep.

Comments:
What the research appears to indicate is that a pacifier at the last sleep, is significantly associated with reduced risk of SIDS.  Generally having a pacifier, appears to offer little protection unless it's in place at the sleep during which SIDS would have occured - futhermore, there also seems to be suggestion of increased risk if an infant normally has a pacifier, but does not have one at the last sleep.

How on earth does a parent guarantee pacifier use will be continued once introduced?  My first had one for a few months, before refusing to take it again - which is not uncommon for the breastfed baby; I'm extremely glad I wasn't aware of this link at the time!  A lot seems to be based on assumption baby will ALWAYS take one when offered.

HOWEVER, we can only really even apply any of this to non breastfed infants, because there simply isn't the evidence to support giving breastfed babies a pacifier.  More on this in a moment...

Two years earlier the AAP had made a similar blanket recommendation, the Academy of Breastfeeding Medicine immediately released a statement here, calling the guideline ill-advised and ill-informed:

As exclusively breastfed infants feed frequently through the night, breastfeeding is thought to reduce SIDS by the same proposed mechanism as supine sleep and pacifiers, namely less deep sleep and frequent brief awakenings. Breastfed babies do not need artificial pacifiers to get stimulation since they already have the protective effect of suckling during the night.

Dr Brian Palmer proposes that as one or two of the studies suggest, using a bottle and pacifier can change development of the throat - placing the infant at risk if the pacifier is not used.  Well worth a read in full here.

There are no studies examining whether pacifiers reduce the rate of SIDS for the exclusively breast (milk) fed infant.  Any study would also have to examine feeding method ie from breast, bottle or both, and also how the mum breastfed ie to a strict three hour schedule with no feeding to sleep and restricted nightfeeds compared to those feeding frequently on demand with baby frequently falling asleep at the breast.  In order to be accurate, it would also need to compare sleep environment - ie has sleep training taken place to try and develop an abnormally long sleep spell; but I'm guessing it's probably not in anyones interest to fund this, certainly no great donation from MAM ;)

The Logic..

A pacifier is ultimately a copy of a nipple, therefore logically any "protection" that may come from a pacifier, would also be obtained from a nipple.  Infants drop a pacifier once asleep, and the guidelines are that it should not be put back in - ie any apparent protection doesn't come from it being constantly sucked.  Yet for some reason, the assumption seems to be that a plastic copy could potentially hold magical powers and lets just assume this will be the case for breastfed infants too, despite the fact they have the real thing.  There is also strong evidence suggestin pacifier use can shorten duration of breastfeeding (with other health implications) and in the early days. introducing a bottle or pacifier can cause real problems to the baby who hasn't yet established the technique required to milk the breast.
If anything what this research does suggest is that instead of scaring mothers their infant will never sleep if they allow them to "use the breast", it would seem prudent to actually encourage mothers to feed their infant to sleep at least in the first six months - so they are falling asleep sucking as per the "last sleep" research.  Certainly it would appear babies are supposed to fall asleep at the breast, as it contains nucleotides that include sleep:

Results published in Nutritional Neuroscience showed that breastmilk produced during the evening and at night contained more sleep-inducing nucleotides than milk produced during daylight hours.  Researchers also found that certain nucleotides, including some that have been shown to induce sleep, demonstrated a circadium rhythm, increasing with the onset of darkness

There is already significant evidence that not breastfeeding is in itself a risk factor for SIDS, and we also know breastfed babies rouse more frequently and sleep lighter than substitute fed peers.  We know oral development is different and we know thymus and other levels of hormones differ - why would we assume a breastfed baby needs a pacifier?

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