Katherine Dettwyler, PhD is a plenary speaker at the upcoming 2015 ILCA Conference, 22-25 July in Washington, DC, USA. Her plenary address will be A Time to Wean: The hominid blueprint for a natural age of weaning in modern humans. She will also present during two breakout sessions, Beauty and the Breast: The cultural context of breastfeeding and Promoting Breastfeeding, Promoting Guilt?.

Kathy Dettwyler, PhD was recently interviewed by Leigh Anne O’Connor, IBCLC on behalf of Lactation Matters.

I first heard Kathy Dettwyler, PhD, speak at a La Leche League (LLL) Conference in New Jersey, USA, when I was nursing my second toddler. I had been a LLL Leader for four or five years and had fallen in love with toddlers who were nursing—mine and others. I started a toddler-focused LLL meeting in addition to the regular support meetings in my area.

Nursing a toddler seemed so natural. I couldn’t imagine mothering without this special tool. I heard so many moms struggling with weaning and with so many voices questioning what seemed right. I knew in my heart it was right, but I couldn’t always answer the questions parents had, the questions extended families had, the questions doctors had. Her presentation was just what I needed.

Recently, I was lucky to be able to pick her brain about nursing past infancy.

LO: Can you tell me how you got interested in breastfeeding, particularly older babies?

KD: I first got pregnant in 1979, when I was in grad school, and I had a dear friend, Martha Toomey, who had a four-month-old she was nursing. When I told her I was pregnant, she invited me to go with her to a La Leche League meeting. I said, “What’s La Leche League?” and the rest, as they say, is history.

I was the youngest child in my family, my older sisters don’t have kids, and I never babysat much, so I was clueless about babies in general. But breastfeeding was easy for me, and as I had always been interested in the interactions between culture and biology, I was fascinated by the cultural differences between La Leche League and the general US culture at the time.

I ended up having to change the topic of my dissertation research at the last minute, and found myself in Mali. I decided to look at how infant formula was impacting the growth and health of children in Mali, only to discover that no one used formula. I did my PhD research on general cultural beliefs and practices about breastfeeding and weaning, and their effects on child growth. In Mali, people used to nurse longer (up to 6 or 7 years for last children), but the “new” style was to breastfeed for only two years, and the women I worked with there started to urge me to wean my daughter when she turned two years of age, so I could get pregnant again—a third cultural viewpoint to contrast to the US mainstream and to LLL.

Eventually, I ended up trying to write a review chapter for a book I was co-editing on what we knew about how long modern humans were evolved to breastfeed, only to discover that no one had ever, EVER asked that question. Lots of “experts” had lots of opinions, but no one had ever tried to answer the question scientifically except for the wonderful Ruth Lawrence, and she was working from outdated information about mammals in general and elephants in particular.

So I started trying to answer the question of how long humans would breastfeed, if not for weird cultural beliefs, by looking at how length of nursing correlated to other life history variables in our closest relatives (the nonhuman primates) and then using variables that aren’t so easily manipulated by culture, like length of pregnancy, when the permanent teeth erupt, average adult female body size, etc., to predict age at weaning in the absence of cultural beliefs. That’s where the 2.5 years to 7.0 years comes from.

LO: What percentage of people are breastfed until natural weaning occurs? In Western cultures? In other cultures?

KD: There is no way to answer this question in a meaningful or scientific way. There are hundreds of thousands of cultures around the world, depending on how one defines the boundaries of a culture. In every culture, there will be variation in age of weaning unless the culture imposes some strict cultural belief on it. There are undoubtedly some cultures where most of the children nurse until they are between 3 and 5 years of age, or longer.

There are also many cultures, including in the United States, Canada, Australia, and the United Kingdom, where some children nurse that long, but most do not. There are also many, if not most, mother–child pairs where weaning is a mutually negotiated process—two people are involved, after all. I nursed my first child for 4 years, then one for only 4 months, then the last for 5.5 years. None of them weaned “on their own,” except my son with Down syndrome, who absolutely refused to nurse after 4 months of age.

LO: Which cultures currently nurse the longest?

There is no way to answer this question meaningfully. There are still a number of cultures around the world where children nurse for many years. We don’t have a snapshot in time of cultural beliefs about nursing or actual practices in terms of length of nursing from most places around the world. All over the world, the general trend is for nursing to get shorter and shorter, or be replaced by formula, except in a few cultures, such as the United States and other Western countries where nursing is trending the other way, with more women nursing and for longer and longer times.

It’s a very similar process to the “Demographic Transition.” There are three stages to infant feeding practices:

Stage I: Everyone breastfeeds for many years, with a shift to shorter and shorter durations, and, eventually, replacement by formula.

Stage II: Most people bottle-feed with formula, and those who do breastfeed only do so for short periods of weeks or months at most, followed by a shift back to longer and longer durations, and fewer and fewer people using bottles and formula.

Stage III: Everyone breastfeeds for many years.

The United States and other Western countries led the way in the transition from Stage I to Stage II, with the wealthier, more educated women leading the way in the transition to bottle-feeding with formula, then these ideas and practices trickling down to those of lower socioeconomic status and less education. About the time those with the least resources] had switched to bottle-feeding, the wealthier, more educated women were switching back to breastfeeding (1960s-1970s).

Likewise, most non-Western cultures were slow to adopt formula feeding, and some of them are just now in the transition between Stage I and Stage II—places like China, where the formula companies are now targeting mothers in a big way as the market for formula wanes in the West.

This view of the “Infant Feeding Transition” is not my own original perceptive insight; it was Margaret Mead herself who first put this forward years and years ago and said it was too bad we couldn’t figure out some way to skip Stage II, since so many children die or are left with impaired cognitive and immune systems from formula.

LO: What are the biggest barriers to normal length nursing?

• Cultural beliefs that breasts are sex objects. They are not. They are mammary glands, but cultural beliefs about the breasts as sex objects are very powerful in a tiny minority of cultures around the world, and these beliefs are largely to blame for the difficulties women in the West have with breastfeeding in public, breastfeeding even in private, getting their husbands to support them, etc. Not to mention female mammary mutilation (breast augmentation surgery), which is analogous to female genital mutilation in so many ways.

• The lack of belief in the power of women’s bodies to function normally.

• The lack of paid maternity leave, or a society where women can combine their productive work and their reproductive work. In much of the world, women do much more work than in the West—hauling water and firewood, chopping firewood, pounding grain into flour, walking for miles every day, growing crops, milking the herds, working at all sorts of other productive tasks, such as weaving and pottery and even in office jobs—but their kids are with them at all times, and they can nurse whenever they want, including in public, and they have many other people to help them care for their kids.

• A misguided notion that normal durations of nursing will make a child clingy and more dependent, a sissy, not capable of independence from the mother. Research has shown that this belief is not just false, but that, in fact, the more children have a secure base in infancy and toddlerhood, through nursing and co-sleeping, the more independent and socially mature they are in later childhood. As well as smarter, and healthier, and nicer, of course.

• A general devaluation of children and a reluctance to give them the time and emotional effort they need and deserve, having kids too close together; I could go on and on and on.

LO: How do you feel about the term “extended nursing?”

KD: I don’t mind “extended nursing” as long as it is clearly and consistently defined. To some people, anything past three weeks is extended, for others, it is one year. I use the phrase to mean “beyond three years,” which is extended relative to cultural norms in the United States and other Western contexts, but, of course, is not at all extended in biological terms. But I don’t get my panty hose in a twist and insist on such awkward constructions as “natural-term” or “full-term” nursing. I would love to see the term “extended nursing” limited to those children who nurse beyond 7 years of age, and yes, there are some, even in the United States, but that isn’t going to happen.

LO: Is there a difference in children who wean naturally from those who are weaned?

KD: This is another unanswerable question. There are, of course, differences in children who nurse for several years versus those who nurse for only a few months or those who are weaned at birth. Is there a difference between my son Alex who “was weaned” at age 5.5 years, by me, versus a fictional child, George, who self-weaned at 2.5 years? No one knows. What kind of differences? How could one ever determine if it was because of the different way they ended up stopping breastfeeding versus one of the thousands (nay, millions) of other genetic, environmental, and cultural differences between Alex and George.

I am all in favor of the wording in the World Health Organization and American Academy of Pediatrics recommendations that mother and child should nurse as long as is mutually desirable. I don’t think mothers should feel any qualms about weaning when they are ready to stop, for whatever reason. The more critical issue is that mothers who want to continue nursing to any age should be supported, not ridiculed, not have their motives questions, and not be charged with sexual abuse or lose custody of their children, as sometimes happens.

LO: Are there health differences and attachment differences between weaned vs. self-weaned children?

KD: No one knows. There is basically no research on differences between children who nurse for varying lengths of time beyond 2 years (2 vs. 4 vs. 6, etc.) either for cognitive functioning, short- and long-term health consequences, emotional health, attachment, etc., just like no one knows the composition of maternal breast milk more than 2 years postpartum. And certainly there is no research I am aware of between those who self-wean at various ages versus those who are encouraged to stop. Remember, too, that “weaning” can happen more than once. I weaned my daughter, my first child, at age 3, then went back to nursing her 4 months later, and weaned her again at age 4.

LO: What is the latest research in breastfeeding older babies and children?

KD: Here’s an excerpt from my “court letter” that cites the only recent research I am aware of:

Thus, while there is not a broad-based research enterprise proving that breastfeeding a child for 3 years provides statistically significant health, cognitive, or emotional benefits compared to breastfeeding a child for only two years, there is no research to show that breastfeeding a child for 3 years (or 4-5-6-7-8-9 years) causes any sort of physical, psychological or emotional harm to the child. This was explicitly confirmed in the 2005 American Academy of Pediatrics Recommendations for breastfeeding the healthy term infant, as well as Karen Epstein-Gilboa’s research, published in her 2009 book Interaction and Relationships in Breastfeeding Families: Implications for Practice.¹

LO: How can mothers best be supported to continue nursing past a year or two?

KD: Families could best be supported in extending breastfeeding by providing:

• A year of paid maternity leave.
• On-site child care facilities, or letting them have their kids with them at work.
• Education for the general public that breasts are not sex objects.
• Education for the general public that nursing beyond age 2-3-4 is normal and healthy.
• Education for the general public on the risks of formula feeding for children, including death, cognitive impairment, immune system dysfunction, chronic diseases, etc.
• Education for the risks of formula feeding for mothers, including higher rates of osteoporosis and reproductive cancers.

LO: What are the biggest myths around nursing older babies?

KD: The biggest myths are:

• They will bite you with their teeth. Yes, they sometimes bite, but so do babies, with their bony gums. It hurts either way and can be easily discouraged
• It will make them homosexual, especially boys. Ridiculous!!
• It will make them clingy and dependent. Not true—just the opposite, in fact.
• They don’t need it for nutrition. There is no better food for children than human breast milk; nothing else comes close. And, of course, it isn’t just, or even primarily, food. Breast milk contains all sorts of factors, many still unrecognized, that help in normal development of the brain, immune system, and other parts of the body. Breastfeeding also helps the child self-regulate their physiological state, to calm them down when hurt, tired, or upset, to make them better when they are sick, to put them to sleep, to lower their blood pressure, to improve nutrient absorption through the gut, etc.
• The idea that breast milk magically turns to Kool-Aid the day the child turns one year of age. There is lots of research to show that breast milk continues to be nutritionally valuable and to have even more immune factors per mL as the child gets older. It never becomes nutritionally valueless.
• Their friends will make fun of them. In my experience, a lot of older nurslings have friends who are also still nursing, and they think everyone at kindergarten goes home and nurses. Why would they think otherwise? If kids do make fun of them, the nursing child can educate the ignorant with a few well-chosen words. Or, as my daughter said to someone in high school who was acting disgusted about learning that a 1.5 year old was nursing, “Look, I’m sure you’re a very nice person, but you’re a complete idiot when it comes to this issue. You obviously don’t know anything about it, so why don’t you just shut up” (paraphrasing, it was many years ago, that daughter is now 34 years old). And even if some kids do make fun of them, so what? We wouldn’t expect a Jewish mom to raise her children Christian to fit in and avoid teasing. We wouldn’t expect a mom to have surgery on her child’s face at age 6 to make him or her more pleasant looking (hopefully) to avoid teasing. Etc., etc., etc. Children are going to make fun of each other no matter what.

LO: Are there any downsides to nursing into preschool age?

KD: Absolutely not. Except having to deal with ignorant people. And, of course, legal trouble for some people in places where the ignorant people are judges, lawyers, and/or work for child protective services and think extended breastfeeding is abuse.

LO: What is the most surprising thing you have learned in your research?

KD: How many people are so ignorant about the function of human breasts and think that they are naturally sexy and that mothers who nurse older children are having sex with their kids.

LO: What is the most unusual nursing story you have encountered?

KD: I’ve heard lots of great stories. I love my friend’s story. She was nursing a five year old and a three year old when she gave birth to twins (unexpectedly—she knew she was pregnant, but not that she was having twins). For a while she was nursing all four kids, but then eventually weaned the 5 year old to try to help get a yeast infection under control. She used to joke that even though she drank tons of water every day, she never peed.

And of course, I love stories like the one where my daughter was flying from Europe to New Zealand by way of China and there was a Chinese baby on the plane without its mother, screaming, and the father couldn’t get any formula mixed up, so my daughter offered to, and did, nurse the baby to sleep. The best part of the story is that she had to get her husband to distract their own little boy so he wouldn’t be upset seeing mommy share “his” milk with another baby. Everyone on the plane was very appreciative.

And of course, I once was interviewing a mom for my dissertation research and she was nursing her two year old, when a one year old walked over and started nursing from her other breast, and she was surprised when I was surprised. It was her grandson and she said, “Doesn’t your mother help you nurse your daughter?” When I said, “No, she lives too far away and doesn’t have little kids of her own any more,” she offered me her sympathy, saying, “That must be really difficult for you.”

LO: Where do mothers find the most support?

KD: For some, it is right there at home with their mother, mother-in-law, sisters, husband, friends, neighbors, and co-workers. For others, it is face-to-face mother support groups like La Leche League, Nursing Mothers Association, and similar groups. Since the advent of the internet, of course, there are now thousands of online support groups, including some targeted specifically to distinct groups, such as disabled mothers, older mothers, African-American mothers, lesbian mothers, mothers nursing toddlers and beyond, etc.

LO: Where do you find participants for your research?

KD: When I was doing research in the mid 1990s on women in the United States who nursed longer than three years, that was in the early days of email and the internet, but I put up info on my website, through LLL, at conferences, through email lists, such as LactNet, etc. Lots of women passed the survey I was doing on to their friends. It isn’t difficult at all to find women nursing kids over three years of age.

Katherine Dettwyler, PhD is an anthropologist and breastfeeding expert who specializes in evolutionary medicine and infant/child feeding practices. She publishes extensively on topics related to breastfeeding, especially the conflicts between biological and cultural breastfeeding wisdom. Katherine is currently an Associate Professor in the Department of Anthropology at the University of Delaware.

Leigh Anne O’Connor is an International Board Certified Lactation Consultant and Parenting Expert. She has over 17 years experience working with families. She is the past President of New York Lactation Consultant Association (NYLCA), a member of International Lactation Consultant Association (ILCA), United States Lactation Consultant Association (USLCA) and a past member of the Bank Street Head Start Health Advisory Board.

¹Epstein-Gilboa, Karen. 2009. Interaction and Relationships in Breastfeeding Families: Implications for Practice. Texas: Hale Publishing.

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