Breastfeeding No Option? Women Need Remedies, Not Bullying

Source: Original cartoon by Alex Martin

Substantial evidence indicates that breastfeeding benefits the health of both mothers and babies. For biologists, this is only to be expected. Mammals, after all, are named after the Latin mamma for teat. Suckling originated in ancestral mammals around 200 million years ago and natural selection has honed it ever since. Female mammals became adapted not only for milk secretion and suckling but also for close mother-infant contact. Health authorities acted on evidence for natural advantages of breastfeeding by encouraging mothers to suckle babies as far as possible. But the widely used slogan “Breast is Best” raises hackles.

Contrary Views

Not everyone welcomes official promotion of breastfeeding. One milestone was Hanna Rosin’s 2009 “case against breastfeeding” in The Atlantic. This fed into the 2015 book Lactivism by Courtney Jung, University of Toronto professor of political science. Lactivism has two main themes, one praiseworthy and the other lamentable.

The first, commendable, theme is that women who do not breastfeed—for whatever reason—should never be bullied. Many women try really hard without success to nurse their babies, and they do not need over-zealous breastfeeding advocates to deepen their disappointment. Other mothers cannot breastfeed for financial or medical reasons. The HIV virus is an oft-cited example, although it is unclear whether breastfeeding increases or decreases transmission risk. Regardless, slogans like “Breast is Best” are no excuse for criticizing women for not breastfeeding. What we need instead is a scientifically-based replication of benefits when women cannot breastfeed.

But Jung’s second theme is systematic belittlement of the scientific evidence for breastfeeding benefits, presented as minimal to non-existent. Enthusiastic breastfeeding advocates do sometimes overstate benefits. Formula-reared babies actually fare remarkably well, especially in view of manufacturers’ feeble attempts to approximate human milk composition. Nevertheless, research has clearly identified many advantages of breastfeeding. While not huge, they are statistically significant.

Assessing the Scientific Evidence

Jung’s discussion of scientific findings—essentially Chapter 3 of Lactivism—is patchy and selective. A key feature is her focus on pediatrician Michael Kramer as the prime source of expert opinion. Note that Jung misrepresents his findings. Tom Bartlett sought comments from Kramer when reviewing Lactivism for The Chronicle of Higher Education. Kramer told him: “I think she chose to ignore some of the science …… I don’t think it’s a balanced summary of the evidence, and I do think it sends the wrong message.”

The fundamental point is that Kramer led the Promotion of Breastfeeding Intervention Trial (PROBIT, 1996-97), described by Jung as “the largest and most authoritative study of the effects of breastfeeding to date”. Kramer was concerned because evidence for breastfeeding benefits came largely from observational studies with no possibility for testing. He hit upon an inspired way of avoiding ethical problems of actual experiments: Taking 31 hospitals, half were randomly selected for specific promotion of breastfeeding (intervention group), while the other half continued existing practices (control group). The Republic of Belarus was chosen as the location for the project.

PROBIT has generated a stream of publications. Before the study began, although most mothers started breastfeeding after birth, many soon introduced bottle-feeding and stopped breastfeeding completely within three months. Strikingly, exclusive breastfeeding of babies at three months of age was more than seven times more likely in the intervention group than in the control group. Moreover, a year after birth, intervention mothers were twice as likely as control mothers to be still breastfeeding.

Note, however, that PROBIT—because of its clever design to meet ethical standards—necessarily underestimates breastfeeding benefits. PROBIT does not compare breastfeeding to bottle-feeding; it compares babies receiving some breastfeeding with others receiving more.

PROBIT neatly confirmed several findings from previous observational studies. A 2001 paper reported a significantly reduced risk of gastrointestinal tract infections (about a third lower) and atopic eczema (down by half) for intervention group babies. By contrast, respiratory tract infection showed no significant difference. Moreover, other PROBIT papers reported no significant positive effects of breastfeeding on height, weight, adiposity, Body Mass Index, blood pressure, diabetes, asthma or atopic eczema in adolescence. For these conditions, confounding factors may have skewed previous observational studies. So the spectrum of breastfeeding benefits is probably narrower than sometimes claimed.

Forest plot showing the odds ratio (estimated likelihood) for SIDS for infants with exclusive breastfeeding of any duration Results from 8 individual studies (blue boxes) have been combined to obtain a single overall assessment (red diamond). The overall result indicates that the risk of SIDS is reduced by almost 75% in exclusively breastfed babies.

Source: Adapted from a figure in Hauck et al. (2011).

Another major breastfeeding benefit indicated by many studies is protection against Sudden Infant Death Syndrome (SIDS). PROBIT yielded insufficient data for statistical tests, but in 2011 Fern Hauck and colleagues published a combined analysis of many previous studies yielding clear evidence of risk reduction. SIDS rates were lower by more than half with any breastfeeding and by almost three quarters with exclusive breastfeeding of any duration.

Bullying Essential Reads

What Are the Differences Between a Bully and a Narcissist?

Let’s Stop Normalizing Sibling Rivalry

Summary of intelligence test results for children in the experimental and control groups of the PROBIT study. The largest differences were found with Verbal IQ (7.5 points) and Full-scale IQ (5.9 points).

Source: Adapted from a table in Kramer et al. (2008).

Importantly, a 2008 paper from PROBIT reported that, when assessed with various intelligence tests at six-and-a-half years of age, intervention group children scored significantly higher—by up 7.5 points (depending on test type)—than control group children. Teachers' academic ratings for both reading and writing were also significantly higher. The team concluded: “These results, based on the largest randomized trial ever conducted in the area of human lactation, provide strong evidence that prolonged and exclusive breastfeeding improves children's cognitive development.”

Mothers Benefit Too

Plot of relative risk of cancer against lifetime duration of breastfeeding in women, showing a progressive downward trend as cumulative breastfeeding increases.

Source: Adapted from a figure provided by the Collaborative Group on Hormonal Factors in Breast Cancer (2002).

In addition to substantial evidence that breastfed infants enjoy multiple benefits compared to bottle-fed babies, advantages of breastfeeding for mothers are also well-documented. Most importantly, breastfeeding is associated with significantly reduced incidence of cancers of the breast and ovaries. Replicating all benefits of breastfeeding is hence supremely challenging. Can we devise ways of reducing cancer risks for women who do not breastfeed?

Setting the record straight

Lactivism’s core weakness is that Jung fails to mention biology or evolution. Witness her absurd statement that “there has never been a time when all women breastfed". If for any substantial period, breastfeeding had been eliminated to the extent seen today, our species would not exist. Suckling in mammals is universal and has that 200-million-year evolutionary history, so how likely is it that we can simply substitute formula for breastfeeding with no downside? No evolutionary biologist would defend this view.

But the elephant in the room is this: Few people today breastfeed to the extent that prevailed for hundreds of thousands of years before our species domesticated milk-yielding mammals around ten millennia ago. Multiple lines of evidence indicate that our hunting-and-gathering ancestors breastfed babies for at least three years, exclusively for the first six months or so and then combined with complementary feeding until weaning. Few mothers today come anywhere near that original pattern. In fact, studies of “breastfeeding” often fail to distinguish between “ever breastfed” (maybe for just a few days after birth) and breastfeeding for a year or more. The few studies that examined benefits in relation to breastfeeding duration reported steady increases over time for both mothers and infants.

Graph showing results from Bayley tests (related to development of intelligence) for infants assessed at 6, 12, 18 and 24 months. Scores increase in a dose-response fashion with duration of breastfeeding (bf).

Source: Adapted from a figure provided by Rogan & Gladen (1993).

Take-Home Messages

Lactivism rightly censures bullying of mothers who do not breastfeed. On the other hand, its seriously misleading disparagement of breastfeeding benefits is downright dangerous. It may reduce pressure to develop really effective solutions for mothers who cannot breastfeed.

Right now, the best advice to new mothers is that they should breastfeed if they can and for as long as possible. Benefits are not huge, but any mother surely wants her infant to have fewer early infections, to have a lower probability of cot death, and to grow up to be as smart as possible. And she will surely prefer a decreased risk of breast and ovarian cancer. However, if for any reason breastfeeding is not an option, every attempt should be made to replicate its benefits. For working mothers, breast-pumping remains a useful (not necessarily easy) option, despite all the negative comments in Lactivism. And if formula has to be used, then it should be optimized. The jury is still out regarding a requirement for omega-3 and omega-6 fatty acids. However, they are known to be important for brain development and human milk contains them whereas cow’s milk does not. So it is wise to opt for a formula that contains them. Any formula used should, in any case, be closely checked to see how well it matches human milk. Over the long term, pressure should be applied to oblige formula manufacturers to work harder to maximize the resemblance to human milk.

P.S. For excellent, just published information from highly relevant anthropological research, see Breastfeeding: New Anthropological Approaches (Oxford, UK: Routledge, 2018), edited by Cecília Tomori, Aunchalee Palmquist & Elizabeth Quinn.