I have been arguing for years that the benefits of breastfeeding have been exaggerated far beyond what the scientific evidence could justify. In large part that exaggeration has occurred because of a massive marketing effort on the part of lactivists who repeated “breast is best” so often that it became conventional wisdom even though it wasn’t true.
It’s been 5 years since the publication, Is Breast Truly Best? Estimating the Effects of Breastfeeding on Long-term Child Health and Wellbeing in the United States Using Sibling Comparisons by Colen and Ramey that found the purported benefits of breastfeeding nearly all disappeared with corrected for confounding variables like socio-economic status and ethnicity. Multiple papers by other authors debunking various claimed benefits of breastfeeding have since been published.
“…[E]xclusive breastfeeding at discharge from the hospital is likely the single greatest risk factor for hospital readmission in newborns.”
A recent paper tactfully titled Is the “breast is best” mantra an oversimplification? summarizes the evidence that the benefits have been overstated and the risks ignored.
The authors note:
Recommendations about breastfeeding — absent critical analysis and removed from context — may overvalue its benefit…
The benefits of breastfeeding for infants have long been touted as numerous and supported by overwhelming evidence…
Massive public health campaigns citing data for the many benefits of breastfeeding have been launched with the goal of increasing the breastfeeding rate…
In recent years, an increasing number of researchers, physicians, and authors have begun to question whether, in the United States, the benefits of breastfeeding children are exaggerated and the emphasis on breastfeeding might be leading to feelings of inadequacy, guilt, and anxiety among mothers…
The authors review the existing scientific evidence in order to bring clarity to the discussion. They start by confirming the well known but small decrease in upper respiratory infections and episodes of diarrheal illness, but they find little support for most other claimed benefits, especially long term benefits.
IQ:
Several studies conducted in developed countries have linked breastfeeding to positive cognitive outcomes in children, including higher intelligence quotient (IQ).
These effects are conflicting, however, in studies that include sibling analysis and ones that control for maternal IQ. In the 2013 WHO meta-analysis, breastfeeding was associated with an increase of 2.2 points on normalized testing when only high-quality studies were included. A 2015 meta-analysis identified 4 high-quality studies with a large sample size and recall time
Obesity:
The relationship between breastfeeding and obesity later in life is debatable. A large, systematic 2014 review of 15 cohort and 10 cross-sectional studies found a significantly reduced risk of childhood obesity among children who were breastfed (adjusted OR=0.78; 95% CI, 0.74- 0.81). However, the review included studies that controlled for different confounders, and smaller effects were found in studies in which more confounders were taken into account.
The 2013 WHO meta-analysis found a small (approximately 10%) reduction in the prevalence of overweight or obese children, but cautioned that residual confounding and publication bias were likely. At 6.5 and 11.5 years of follow-up, PROBIT failed to demonstrate a protective effect for exclusively or “ever” breastfed infants. Sibling analysis similarly fails to demonstrate a statistically significant relationship.
A 2015 meta-analysis of 23 high-quality studies with a sample size >1500 children and controlled for important confounders showed a pooled reduction in the prevalence of overweight or obesity of 13% (95% CI, 6-19).57 The protection in this meta-analysis showed a dilution of the effect as the participants aged and an inverse relationship of the effect with sample size.
Breastfeeding is, therefore, unlikely to play a significant, if any, role in combating the obesity epidemic.
NEC (necrotizing enterocolitis)
In preterm infants, breastfeeding has been associated with a lower rate of necrotizing en- terocolitis. In the 2007 Agency for Healthcare Research and Quality report, the association was found to be only marginally statistically sig- nificant, and the authors warned that, first, evidence is old and heterogeneous and, second, present preterm formula is much different than the formula used in earlier studies of preterm infant nutrition and necrotizing enterocolitis. A 2012 Cochrane review included newer stud- ies in its analysis but reached the same conclusion on the quality and heterogeneity of available evidence, with a NNT of 25.
SIDS (Sudden Infant Death Syndrome)
There is a statistically significant association between sudden infant death syndrome (SIDS) and feeding method. Infants whose cause of death is SIDS are approximately one half as likely to have been breastfed as matched controls…
The protective effect exists for any amount of breastfeeding and is stronger for exclusive breastfeeding, suggesting a protective role — not simply an association. Caution should be employed with this conclusion, however, because the studies included in the meta-analysis used univariate analysis primarily and did not control sufficiently for known confounders. In addition, the authors warn that publication bias might overestimate the association…
Assuming a protective role, available data suggest that more than 3500 infants need to be breastfed to prevent one case of SIDS.
Does breastfeeding save lives?
No clear association has been found between mortality and breastfeeding status in developed countries, except for the association with SIDS.
And breastfeeding has risks including dehydration, failure to thrive, weight loss, and hyper- bilirubinemia.
…[E]xclusive breastfeeding at discharge from the hospital is likely the single greatest risk factor for hospital readmission in newborns. Term infants who are exclusively breastfed are more likely to be hospitalized compared to formula-fed or mixed-fed infants, due to hyperbilirubinemia, dehydration, hyper- natremia, and weight loss (number needed to harm (NNH)=71). For weight loss >10% of birth weight with or without hospitalization, the NNH for breastfed infants is 13.
Many of these hospitalizations and events could be avoided with appropriate monitoring and medically indicated supplementation; the likelihood of long-term harm is low. Formula supplementation is often avoided if possible in hospitals to promote exclusive breastfeeding; however, several small randomized clinical trials have demonstrated that limited formula supplementation in breastfed infants does not affect the breastfeeding continuation rate at 3 and 6 months, and, therefore, might be a way to decrease in- fant rehospitalization.
The bottom line?
The evidence for infant breastfeeding status and its association with health outcomes faces significant limitations; the great majority of those limitations tend to overestimate the benefits of breastfeeding. Nearly all evidence is based on observational studies, in which causality cannot be determined and self-selection bias, recall bias, and residual confounding limit the value or strength of the findings.
Is breastfeeding advocacy harmful?
The “Ten Steps to Successful Breastfeeding” program of the Baby-friendly Hospital Initiative (BFHI; launched by UNICEF and WHO) has come under scrutiny because of an increasing number of reports of sudden unexpected postnatal collapse; fall injuries; modeling and encouragement of unsafe sleep practices; an overly rigid resistance to the use of formula supplementation; and the ban on pacifier use…
Some of the “Ten Steps,” such as the call for skin-to-skin care and 24-hour rooming-in, have well-established benefit yet, when performed without supervision, can have the rare but serious unintended consequences of sudden unexpected postnatal collapse (the incidence of which may be higher than that of SIDS) and unsafe sleeping practices.
Furthermore, despite evidence that early formula supplementation, when medically necessary, does not adversely impact the breastfeeding rate, the “Ten Steps” program advises that giving formula before breast milk comes in might “lead to failure to breastfeed.”
Similarly, the ban on pacifiers is contrary to available evidence. The use of pacifiers before last sleep is more protective against SIDS than breastfeeding (NNT=2733) …
What about the harms to mothers?
The literature that does investigate harm consistently finds that women who have difficulty breastfeeding or choose formula feeding report feelings of inadequacy, guilt, loss of agency, anxiety, and physical pain during breastfeeding that interferes with 1) their ability to bond or otherwise care for their infant and 2) competing work obligations…
What do mothers need to know? The authors offer compelling statistics about both short and long term benefits including:
Greater than 99% will not realize benefit from either the prevention of SIDS … or from improvement in long-term health measures …
Balancing the abundant, but often limited-quality, data on the benefits of breastfeeding and the sheer lack of data regarding the risks of advocacy represents a clinical and an ethical challenge for physicians. It is a challenge that can only be resolved through individualization of care and shared decision-making, in which the physician is expert on the benefits of breastfeeding, and the mother is expert on the personal circumstances to be weighed against those benefits.
Her baby, her body, her breasts, her choice!
