Any Breastfeeding — Even If Combined With Formula — Cuts SIDS Risk In Half – Forbes
Past research findings have shown that breastfeeding cuts the risk of sudden infant death syndrome (SIDS) in half, but those studies seemed to suggest that only exclusive breastfeeding for six months decreased the risk. Now a new look at eight studies together finds it doesn’t take long, or much, breastfeeding to get that benefit.
In fact, just two months of breastfeeding, even combined with formula, reduces SIDS risk, according to the new study in Pediatrics. Not only does the evidence therefore confirm SIDS risk reduction, but it also means mothers doing combination feeding can take heart that their children get the same benefit. And the whole idea that “formula feeding doubles SIDS risk,” as some extreme breastfeeding advocates have suggested, is just flat wrong.
“This analysis does not reveal any advantage to exclusive breastfeeding over partial breastfeeding, which may be reassuring to some parents who cannot or do not wish to exclusively breastfeed their infant,” the authors wrote.
This new study, led by John M.D. Thompson, PhD, from the University of Auckland in New Zealand, also included highly regarded authors in SIDS and safe sleep, such as Rachel Moon, MD, and Peter Blair, PhD, and breastfeeding researcher Fern Hauck, MD. The researchers analyzed the data from eight case-control studies involving 2,267 infants who died from SIDS and 6,837 infants who did not die.
In a case-control study, scientists compare the histories and experiences of a population of babies who died from SIDS to a population who did not. Each infant that died is matched to one or two or more infants (depending on the study) with the same age, sex and pregnancy week of birth (to account for prematurity) who survived.
Then researchers can look back to see which babies in each population were breastfed, how much and how long and what other factors they do or don’t have in common that could affect their risk of SIDS. For example, factors that increase the risk of SIDS include a baby sleeping on his or her stomach, being exposed to cigarette smoke during pregnancy, prematurity, soft bedding, blankets and sharing a bed.
Different studies on the same topic sometimes reach different conclusions because they compare different factors between the children, use different statistical analysis methods, have larger or smaller populations of infants or have some other difference in how they were conducted. Analyzing a group of studies together usually provides stronger evidence about the link between a behavior (breastfeeding) and an outcome (SIDS or survival). But it also means the studies might differ so much that it’s not possible to get a definitive, precise answer for all children.
That was the largely the case in this study: The researchers said the information collected in each study about the children varied slightly, so they were not able to make adjustments to account for all the possible factors that could influence SIDS risk. But they had enough data to crunch the numbers and find some broad reliable conclusions:
- Breastfeeding of any kind for less than two months does not reduce (or increase) SIDS risk.
- Any breastfeeding for 2-4 months reduces the risk of SIDS by about 40%. That means for every 10 non-breastfed babies who were going to die of SIDS, four of them would survive if all of them were breastfed instead. (There is no way to know which babies would have survived, and six will still die since other factors influence SIDS as well.)
- Any breastfeeding for 4-6 months reduces the risk of SIDS by about 60%.
- Any breastfeeding for longer than 6 months reduces the risk of SIDS by about 74%
- Exclusive breastfeeding for 4-6 months reduces the risk of SIDS by about 41%—almost identical to the finding with any kind of breastfeeding, including babies who are breastfed and formula-fed.
- Exclusive breastfeeding for 4-6 months reduces the risk of SIDS by 54%.
It’s not fully understood why babies appear to receive some protective benefits against SIDS if they are partly or fully breastfed. Currently, scientists believe that three overlapping underlying causes likely play the biggest role in SIDS, called the “triple risk model.” Those factors are being in a vulnerable developing period in the infant’s life (especially 2-4 months old), exposure to some sort of environmental trigger (inadequate breathing room, tobacco smoke while in the womb, etc.), and an underlying neurological, genetic or biological condition that makes it difficult for the baby to wake up.
Breastfed babies wake up more easily than exclusively formula-fed babies, so that may be one reason breastfeeding appears to affect SIDS risk. Babies also receive immune benefits from breastfeeding which can reduce their risk of a viral infection. Viral infections can increase SIDS risk. Several other properties of breastmilk may also reduce risk of SIDS through their influence on brain development, the authors suggested.
The authors also do not know why exclusive breastfeeding did not appear any more protective than partial breastfeeding. One possibility may relate to socioeconomic status: women who breastfeed tend to have more education and income, and SIDS tends to be more common among families with lower income and education.