Yesterday I wrote about the disabling flaw that renders meaningless nearly every study that purports to show the benefits of breastfeeding.
Most breastfeeding studies compare babies who are breastfed with babies who are not breastfed at a moment in time weeks or months after birth (3 months, 6 months, one year). But when we only look at breastfeeding status at a particular moment in time, babies who develop complications from breastfeeding will mistakenly end up in the formula group. If we want to know the difference between babies who are breastfed and those who are formula fed, we must place the babies who failed to thrive on breastfeeding in the breastfeeding group, NOT the formula group.
Breastfeeding, like homebirth, must be studied with intention to treat analyses.
How could we correct the disabling flaw? The same way we do in research on homebirth: we compare groups based on intention. Just as homebirth studies compare intended homebirths with intended hospital births, breastfeeding studies should compare intended breastfeeding with intended formula feeding. This is known as an intention to treat analysis.
What happens when we take intention into account? The purported benefits of breastfeeding disappear!
To my knowledge there is only one study that has explicitly taken intention into account, The best of intentions: Prenatal breastfeeding intentions and infant health.
The authors looked at more than 1000 women and categorized them based on whether they intended to breastfeed or not.
They noted:
…Approximately one-third of mothers who intend to exclusively breastfeed are able to achieve this goal. There are several exogenous factors that may prevent mothers from fulfilling their intentions. For example, biological barriers include low milk supply, pain, infections (mastitis), or clogged milk ducts. The baby may have a poor latch, be an ineffective nurser, or have food intolerances…
Those babies belong in the breastfeeding group, NOT the formula feeding group where nearly all studies on the purported benefits of breastfeeding put them.
The authors looked at three infant health outcomes: ear infections, respiratory syncytial viruses (RSV), and antibiotic usage in the infant’s first year. They found that women who intended to breastfeed had infants with better health outcomes REGARDLESS of how soon babies with breastfeeding complications were switched to formula.
What’s going on?
Breastfeeding in industrialized countries is socially patterned. Privileged women are far more likely to breastfeeding. It is privilege that leads to the purported benefits of breastfeeding, not breastfeeding itself.
To my knowledge there is no other intention to treat analysis of breastfeeding. But since breastfeeding is socially patterned, we can approximate intention to breastfeed by correcting for social-economic factors.
The 2014 study Is Breast Truly Best? Estimating the Effects of Breastfeeding on Long-term Child Health and Wellbeing in the United States Using Sibling Comparisons corrected for these factors by looking for the differences between breastfed and formula fed infants WITHIN families. When they did, there was no difference between breastfed and bottle fed babies.
Most studies of breastfeeding that correct for socio-economic factors yield similar results: the purported benefits of breastfeeding are markedly attenuated or disappear altogether.
There is another indirect way to account for intention to breastfeed vs. intention to formula feed. We can look at overall population statistics. For decades, lactation professionals have made detailed predictions of decreased infant mortality, severe morbidity and healthcare expenditures with rising breastfeeding rates. Though breastfeeding rates have soared in the US and other industrialized countries, NONE of those predicted benefits have occurred. One possible reason for this is that the benefits of breastfeeding are trivial.
Another possibility is that the purported benefits of breastfeeding are entirely offset by complications of breastfeeding. Exclusive breastfeeding has become the leading cause of newborn re-hospitalization leading to tens of thousands of re-hospitalizations each year at a cost of hundreds of millions of dollars. Aggressive breastfeeding promotion is literally making babies sick!
The bottom line?
Any study that claims breastfeeding has benefits but doesn’t use an intention to treat analysis is improperly done and therefore the results are deeply suspect.
That explains why the benefits of breastfeeding disappear when we correct for maternal socio-economic status and why the predicted benefits of increased breastfeeding rates have never come to pass.
