Does breastfeeding prevent SIDS?

Baby feeds on MOM's breasts

It is now widely accepted that breastfeeding prevents SIDS (Sudden Infant Death Syndrome), but is that what the scientific evidence really shows?

The short answer: yes, but it’s complicated.

[pullquote align=”right” cite=”” link=”” color=”” class=”” size=””]Yes, but it’s complicated.[/pullquote]

Yesterday I wrote about the claim that roomsharing prevents SIDS and concluded that the evidence is both extremely limited and very weak. In contrast, there have been a multitude of studies supporting the claim that breastfeeding prevents SIDS; the problem is confounding variables and exaggeration of the benefits.

The following graphs illustrate the difficulties.

This first set of graphs comes from the 2016 paper Overall Postneonatal Mortality and Rates of SIDS by Goldstein et al. The first graph shows the decline of SIDS and non SIDs infant and postneonatal deaths over the past 3 decades. The second graph breaks out trends in various causes of unexplained neonatal mortality of which SIDS is only one possible diagnosis.


The authors explain:

It has been recognized that SIDS mortality has decreased since inclusion in the International Classification of Diseases in 1973, decades before the promotion of supine sleep positioning. Without diminishing the remarkable contributions of BTS, this 30-year analysis raises important considerations that changes in mortality were also associated with concurrent influences on postneonatal mortality and those affecting intrinsic risk… Additional support that SIDS and non-SIDS mortality share common influences is provided by the cluster analysis, where SIDS mortality trends most closely follow specific conditions with improvements attributable to advances in prenatal and neonatal care.

In other words, there are a myriad of confounding variables that plague all studies of SIDS. The recent decline in SIDS deaths takes place against the background of an overall decline in postneonatal mortality, an overall decline in prone infant sleeping, and an improvement in classifying deaths that are typically attributed to SIDS.

Most studies claiming that breastfeeding is protective against SIDS are case-control studies. Both cases and control should presumably reduce the effect of background changes in SIDS incidence. However, the ambiguity and changing classifications of previously unexplained infant deaths/SIDS deaths could have a disparate impact.

The authors note:

Although some changes in diagnostic preferences may reflect attitudes toward particular nomenclature, such as the use of “cause unknown” instead of “SIDS,” others imply significant differences in the decision-making process for the classification of sudden infant deaths. The increased use of “accidental suffocation and strangulation in bed” instead of “SIDS,” for example, reflects awareness of potentially lethal asphyxial conditions from improved scene investigations but also debatable judgments about their contribution to death in an assumed normal infant…

Breastfeeding rates are closely associated with socio-economic status. Are there differences in cause of death diagnosis between wealthy communities and poorer communities? We don’t know.

Keeping these issues in mind, let’s look at the actual studies that analyze the impact of breastfeeding on SIDS rates.

Breastfeeding and dummy use have a protective effect on sudden infant death syndrome by Alm et al. is a literature review on the protective effect against SIDS of both breastfeeding and pacifier use.

We conducted a literature review on the effect of breastfeeding and dummy (pacifier) use on sudden infant death syndrome (SIDS). From 4343 abstracts, we identified 35 relevant studies on breastfeeding and SIDS, 27 on dummy use and SIDS and 59 on dummy use versus breastfeeding.

What did they find?

We examined 17 observational studies and found that breastfeeding was reported to have provided a protective effect on SIDS in ten studies. No protective effects were found in the other seven.

All three of the meta-analyses that our search identified showed that breastfeeding had a protective effect on SIDS.

How about the impact of pacifiers?

We found 11 observational studies that consistently showed a risk reduction of about 50% if the infant used a dummy.

There were also two meta-analyses that gave approximately the same odds ratio of about 0.5.

What was the impact of pacifier use on breastfeeding rates?

[F]ive randomised controlled studies (RCTs) have been performed to date. Four of them did not find that a dummy reduced the duration of breastfeeding, while one found an increased risk of earlier weaning.

In 2011, Jaafar conducted a meta-analysis on the RCTs carried out by Jenik and Kramer, which concluded that using a dummy did not affect the chance of exclusive breastfeeding at three months.

This plot of pooled odds ratios shows the impact of breastfeeding and pacifiers on SIDS and well as the impact of pacifiers on breastfeeding. It demonstrates that pacifier use reduces the risk of SIDS as much or more than breastfeeding!


More importantly, the protective effect of pacifiers or breastfeeding is dwarfed by the harmful effect of bed sharing. While pacifier use and breastfeeding appear to decrease the risk of SIDS by 50%, bedsharing increases the risk of SIDS by 400% or more.

So does breastfeeding prevents SIDS?

The evidence suggests that it does, but using a pacifier has an equal if not greater effect on reducing the risk of SIDS, and avoiding bedsharing has a far greater protective effect than either. Of course, placing an infant to sleep on her back has the greatest protective effect of all.

Sadly the lay literature does not accurately portray the risks. That’s because lactivists are so intent on promoting breastfeeding  that they have exaggerated its benefits, minimized the benefits of pacifiers and, to a large extent, ignored the risks of co-sleeping. Moreover, lactivists have failed to situate the benefit of breastfeeding in preventing SIDS within the larger context of the risks of insufficient breastmilk which can cause seizures, permanent brain damage and death.

Should you breastfeed if you can produce enough milk? Sure; it can reduce the risk of SIDs. But you can also give your baby a pacifier which reduces the risk of SIDS by the same amount. And the benefit of breastfeeding is dwarfed by the risk of co-sleeping.

If we truly want to save lives we should be aggressively promoting pacifier use and strongly discouraging co-sleeping. And breastfeeding can help, too.