« How agreeable are econ bloggers? | Main | Markets in everything »
The Case Against Breast Feeding
Hanna Rosin's article on breastfeeding in the latest Atlantic is excellent and would make a topical and accessible introduction to causality studies in an econometrics or statistics class. (And lest that sound damning it's also a great read.)
The general point will be familiar to the audience at Marginal Revolution. The studies that show breastfeeding leads to lower weight, fewer ear infections, less allergies, less stomach illnesses and so forth are almost all observational studies.
An ideal study would randomly divide a group of mothers, tell one half to breast-feed and the other not to, and then measure the outcomes. But researchers cannot ethically tell mothers what to feed their babies. Instead they have to settle for “observational” studies. These simply look for differences in two populations, one breast-fed and one not. The problem is, breast-fed infants are typically brought up in very different families from those raised on the bottle. In the U.S., breast-feeding is on the rise—69 percent of mothers initiate the practice at the hospital, and 17 percent nurse exclusively for at least six months. But the numbers are much higher among women who are white, older, and educated; a woman who attended college, for instance, is roughly twice as likely to nurse for six months.
Moreover, the better we control for other factors that might account for differences in child outcomes between mothers who breastfeed and those who do not, the less evidence there is for breastfeeding's benefits. Even looking at children within the same family (still far from the gold standard of randomization), shows many fewer benefits from breastfeeding than studies that look across families. Some modest evidence suggests a gain in IQ and better evidence suggests minor improvements in avoiding some diarrhea. Rosin does not discount these benefits (so the title of her piece is unnecessarily sensationalistic) but she very appropriately does point to opportunity cost.
The debate about breast-feeding takes place without any reference to its actual context in women’s lives. Breast-feeding exclusively is not like taking a prenatal vitamin. It is a serious time commitment that pretty much guarantees that you will not work in any meaningful way. Let’s say a baby feeds seven times a day and then a couple more times at night. That’s nine times for about a half hour each, which adds up to more than half of a working day, every day, for at least six months. This is why, when people say that breast-feeding is “free,” I want to hit them with a two-by-four. It’s only free if a woman’s time is worth nothing.
One final point, Rosin's article is also usefully read as a study in propaganda and social psychology.
Posted by Alex Tabarrok on April 1, 2009 at 07:39 AM in Economics, Education, Medicine, Science | Permalink
Comments
I have a near-13 month-old and another on the way in a couple of months. I was all about breastfeeding from the giddy-up and couldn't understand why anyone would subject their precious baby to formula. Then I had my daughter and learned real quick that breastfeeding, though a natural function, is also a learned skill that not all mothers and babies can master. I think to some extent Dr. Sears and La Leche have hindered breastfeedng by insisting so forcefully that it is so simple, easy, and anyone can do it. It makes women feel like failures if they can't get milk to flow or the baby to latch instantaneously. Instead mothers should be told, "this is work, a lot of work, and you can't get your husband to share the burden. But if you are willing to stick through it, it can be very rewarding."
And though I'm very glad I did breastfeed my daughter, and I plan to breastfeed the new kid when he arrives, I will say that, a) I think my needing to pump at work three times a day hastened my boss's willingness to lay me off, and b) my daughter has had colds nearly every month since entering daycare at 12 weeks, so breastmilk's immune-bolstering properties haven't been as obvious to me as they are to Dr. Sears, et al.
Posted by: Christina at Apr 1, 2009 12:48:50 PM
"It is a serious time commitment that pretty much guarantees that you will not work in any meaningful way."
My girlfriend breastfeeds our eight-week old daughter part time and "pumps" the rest of the time. The baby has not had as much as a taste of formula. The mom works five hours per day week days and eight hours on weekends for a 41 hour work week.
Does that qualify as meaningful?
Posted by: rto at Apr 1, 2009 12:52:53 PM
Charlotte--
The full quotation was "sitting half-naked in public for the tenth time that day". Our children fed at most every hour to ninety minutes. Ten to fifteen hours is a long time to spend without access to a bathroom, or any privacy. And she also writes that she "dutifully breast-fed each of my first two children". If modesty is important to you, you can use a shawl and by her third child, she must know this.
Breastfeeding can be difficult, it can be painful (especially at first), and it's not for everone, but her stories didn't ring true. They sounded like hyperbole and exaggeration to me.
Posted by: MostlyAPragmatist at Apr 1, 2009 1:04:53 PM
I get it.
My point is that the medical people push breast feeding like they came up with the idea.
We lived through it. My wife did it as long as she could, then had to quit. She felt bad about it because she doesn't have my personality that says the baby gets to suck as long as we can stand it and all the pontificators can bite me.
Posted by: Andrew at Apr 1, 2009 1:08:16 PM
In fact, we managed to eke out the worst of both! We pumped so I could get some of the bonding specialness. Not that I'd trade it.
Posted by: Andrew at Apr 1, 2009 1:09:42 PM
My wife did it as long as she could, then had to quit. She felt bad about it because she doesn't have my personality that says the baby gets to suck as long as we can stand it and all the pontificators can bite me.
Ha-ha, and here it is! The breastfeeding advocates (professional and amateur) know that women fret about everything WRT their babies, and so can easily be bullied. Have a look at any pregnancy magazine (which I see a lot of in my OB's office every other week), and you will see product after product advertised that has no real value, but is preying on mothers who are willing to do anything for their babies.
When I had to quit breastfeeding due to my latest pregnancy, I felt terrible guilt about it and cried. But the sky did not fall, and my child continued to thrive on formula. And even having the benefit of some distance from it and the knowledge that I'm doing the best I can does not completely assuage my guilt. It is, as another commenter said, a mental illness.
There is a good reason women are so mentally ill over their children: if not the species would not survive. If men got pregnant, abortions would be the norm. Men can't fathom giving up authority over your body and mind to a parasite for 9 months + however long you breastfeed. Women are hardwired to make those sacrifices and cry about it if they aren't doing it well enough. It's not fair, and it's certainly a pain, literally and figuratively, but it's the way life is.
Posted by: Christina at Apr 1, 2009 1:26:26 PM
Take this for what its worth, my sample of one…
My wife could not breast feed due to post partum HUS. Initially sad that we couldn’t breast feed but very thankful to have her alive.
Our son was exclusively bottle fed and goes to day care. Mercy me! We are about as close to 50/50 caregivers as mom and dad can be.
He will be turning two next month. Very connected and close to both mom and dad. He is healthy, curious, bright eyed, talks with remarkable clarity in up to 8 word strings, he has a great memory of people, names places and events. He is well behaved, sleeps well, and gets colds with the same frequency as his breast fed ‘classmates.’
Our friend down the road: 3.5 year old exclusively breast fed, stay at home mom. Her son is also bright eyed and reasonably healthy. But despite the breast and home care he is speech delayed, tantrum prone, and has asthma.
What’s going on here? Genetics, parental involvement, appropriate discipline, enriched environment, quantum fluctuation. All of the above I suspect.
Compared to proper bottle feeding with modern formula, breast is one marginal effect in the care and feeding of a child. The whole parenting strategy/partner/family/life continuum and gene endowment are far more important.
If you can b-feed and make it all work, great. You MIGHT have one more box checked on the positive side.
If you can’t or just don’t want to, great. Appropriate parenting and the genes you pass to your offspring will triumph whatever way you choose.
It’s a system.
Posted by: tony at Apr 1, 2009 1:26:31 PM
This is why, when people say that breast-feeding is “free,” I want to hit them with a two-by-four. It’s only free if a woman’s time is worth nothing.
Garbage. If you're a mother at home taking care of your children, the marginal cost of breastfeeding is zero. Your time isn't worth nothing, but we're talking about time that you would otherwise be bottle-feeding the baby, or cuddling the baby, or playing with the baby.
If you choose to work outside the home and have the child's father provide primary childcare, or contract the job out to a third party, the equation is rather different, but once you have made the decision to stay at home with the kids, economically, breastfeeding is almost a no-brainer. (And, of course, breasts are much more portable than bottles...)
Note that the cost changes at the margin. The mother can easily get exhausted if she does around the clock feedings (newborns usually eat every 3 hours, around the colck; for some each feeding takes an hour - not much time for mother to sleep or do othetr things to stay sane!).
Yes, newborns feed a lot, and getting a successful latch can be difficult at first. After a couple of weeks, though, most moms and babies can nurse lying down in bed. If mom and baby share a bed, mom doesn't really have to come fully awake in the middle of the night to help baby latch on. Staying in bed vs getting up and sitting in a chair makes a huge difference in the morning.
Posted by: Sam at Apr 1, 2009 1:38:01 PM
I am a scientist, but not a social scientist. Why is it unethical to design an actual study?
Posted by: Yancey Ward at Apr 1, 2009 1:49:02 PM
I found the headline and lead into the article to be very misleading. The author does not present a case against breastfeeding. She breastfed three kids for gosh sakes! Rather she presents the case against the breastfeeding zealots, who treat it as an almost religious experience. If she has a more grounded, practical understanding now better still.
Posted by: Brendan at Apr 1, 2009 2:07:48 PM
Rosin does not set up her alternate hypothesis particularly well. Like some others have pointed out, bottle feeding takes some time as well, in addition to the prep and clean up time. So there is a non-zero opportunity cost for bottle-feeding as well.
Nor is breastfeeding incompatible with working outside the home. In fact, it's easier for women in white collar, higher income jobs. I am currently nursing my second child, and in my seventh month of pumping. I am fortunate that for each child I had a job with an office that locked and could pump at my desk without interrupting work. As such, my choice to breastfeed did not significantly burden my employer.
I merely offer my experience as a data point that it is possible to breastfeed and work outside the home. While the plural of anecdote is not data, I personally know several other women who managed to successfully breastfeed and hold down a job outside the home full time. It is by no means impossible, though it does involve making a choice.
It is a pity that Rosin is not comfortable enough with her choice that she chooses to impute her guilt to the rest of us.
Posted by: pwdcrazy at Apr 1, 2009 2:39:35 PM
Is this advice only true for human babies or for cat babies too?
Posted by: Kent B at Apr 1, 2009 2:40:51 PM
Yancey,
the article says that it would be unethical if doctors "tell" young mothers whether to do that or not. It depends on what you mean by tell, but randomized trials have been done on doctors recommending (or not) breastfeeding, e.g. this one.
Posted by: LemmusLemmus at Apr 1, 2009 2:56:44 PM
You can also drastically cut down on prep time for bottle feeding at the expense of some green cred. When my siblings were born, my parents used bottles with disposable liners. No boiling, no sterilizing, no cleaning, just fill it up and feed, you can even fill it with pumped breast milk.
Posted by: Sbard at Apr 1, 2009 2:58:59 PM
Lost in the comments on this article is that a mother need only breastfeed for six months of her child's life. Assume she spends three months at home with the newborn. Then there's three more months to balance breast-feeding with work. It's a temporary situation. I could see the problems if it went on for years, but for three months I'd think the inconvenience would be tolerable for most women.
(This doesn't apply to mothers who can't/won't breasfeed for other, perfectly valid reasons.)
Posted by: Lisa at Apr 1, 2009 3:04:47 PM
Hi Alex. Can I talk you into giving this evidence a second read?
You say: "Even looking at children within the same family (still far from the gold standard of randomization), shows many fewer benefits from breastfeeding than studies that look across families. Some weak evidence suggests a gain in IQ and minor improvements in avoiding some diarrhea."
But the evidence for diarrhea came from a genuine random assignment study, not the study you linked to. And the evidence for IQ in the study you referenced was selectively quoted by Rosin. The actual evidence for beneficial effects of breastfeeding in that article's fixed effects analysis was stronger than your quote above indicates.
Here is my review of the evidence, along with comments from the study's authors.
http://usfoodpolicy.blogspot.com/2009/03/oh-really-hanna-rosin-in-atlantic-makes.html
What do you think?
Posted by: Parke at Apr 1, 2009 3:35:35 PM
If breastfeeding really can raise IQ a number of points, that's a huge fact, since very little else can be shown to improve IQ in the long run.
I've long pointed out that lower breastfeeding rates among African American women might account for some of the notorious one standard deviation (15 point) difference in average IQ found between black and white Americans.
Back in the 1990s, about 60% of white women breastfed versus about 30% of black women. If breastfeeding really can raise IQs by 5 points, as some Scandinavian studies showed, then raising black breastfeeding rates to the white level would close the notoriously socially deleterious white-black 15 point IQ gap by about one-tenth. In terms of cost per average IQ point gained, a breastfeeding promotion campaign aimed at black mothers would be dramatically more effective than any other plausible social intervention.
Granted, those are back-of-an-envelope calculations based on studies that aren't definitive. But, still, does anybody have a more potentially cost-effective plan for raising black average IQs?
Posted by: Steve Sailer at Apr 1, 2009 4:55:43 PM
Parke,
Thanks, I was not as clear as I could have been. I meant that the evidence on IQ was weak and the evidence (which is good) on diarrhea showed a fairly minor improvement.
I think the evidence on IQ is weak because the study is intra-family and there are many differences between siblings (older siblings tend to have higher IQ, for example, since older siblings are more likely to have been breast fed this could confound the analysis.) In addition, the data is retrospective.
I agree, however, with your point that the lack of significance is less damning when the coefficient estimates are reasonably similar - this is a very good point.
I'm also not one to discount the role of a few IQ points and tend to agree with Sailer on this point.
Alex
Posted by: Alex Tabarrok at Apr 1, 2009 5:35:06 PM
Lots of woman breastfeed while working full time. You can pump milk, supplement, have a daycare center at work, or even go home for lunch which is what I did. What working mothers can't to is hang around at playgrounds talking about it. Decades ago breastfeeding was much less common than it is now for middle class mothers but more common among the poor. It was the studies performed then that convinced doctors of the benefits of breastfeeding. It really doesn't matter whether it is the quality of the milk or that that breastfeeding makes women into better mothers if the effects are positive for the babies.
Posted by: joan at Apr 1, 2009 5:59:11 PM
Bill Gates recently admitted that his foundation has wasted $2 billion implementing the "small schools" panacea made popular by people like Bill Ayers (whose brother Rick Ayers got $1 million from Gates for small schools at Berkeley High).
In contrast, Gates could have spent, say, $50 million on gold standard studies of breastfeeding. If they didn't show a boost in IQ (which Gates is obsessed about in his personal life), then he's out $50 million, and science has progressed. If they did show a boost in IQ, then Gates could have dropped, say, $500 million on a marketing campaign to promote breastfeeding, especially among targeted demographics (buying commercials on BET is cheaper than on CBS).
Posted by: Steve Sailer at Apr 1, 2009 6:04:15 PM
By the way, the upcoming $3 billion dollar state-of-the-art National Children's Study, which will track 100,000 children from before birth through age 20, including their DNA(!), could be used to answer questions about breastfeeding, since everything else about the children will be measured.
Does anybody know if the National Children's survey will track breast-feeding?
http://www.nationalchildrensstudy.gov/Pages/default.aspx
Posted by: Steve Sailer at Apr 1, 2009 6:52:59 PM
As a stay-at-home dad with a 4 year old and an infant--both raised on breast milk--I feel under-represented in the comments section!
My wife pumps and I do most of the feedings from a bottle. I don't understand why so many people have echoed the view that a woman breastfeeding her child can't work full time. My wife was on the wards during her residency with our first child!
I must be married to superwoman....
Posted by: dsm at Apr 1, 2009 6:58:20 PM
Fair enough! Thanks for responding. It's your bad luck to make such a good point about teaching principles only to have readers like me quibble who care mostly about the substance of the example instead of the teaching point.
Posted by: Parke at Apr 1, 2009 8:23:35 PM
I've just done a lot of work related to this area (on a patent infringement lawsuit about a prenatal & lactation vitamin supplement), and at least as far as the nutritional aspects are concerned, there's no significant difference between breast milk and formula at this point. There used to be (in the 80s), but a lot of work in the 90s went into improving the makeup of formula to mimic the macro- and micronutrient content of breast milk. For example, infant formulas prior to 1990 typically had little to no omega-3 fatty acids; now they all do. To the commenter who mentioned that cow's milk is unnatural--it is, and that's why infant formulas use heavily modified cow's milk.
The reason that controlled studies in this area have ethical problems is primarily because the child can't consent. At least that's what I was told by a top nutrition researcher in the field.
There might be bonding benefits to breastfeeding as opposed to formula feeding; there may be some difference with the antibodies in breast milk (though it's slight at best). But nutritionally, if you're having a baby today, there's no significant difference between breast milk and formula.
Posted by: Brian at Apr 1, 2009 8:29:38 PM
@brian -- Of course infants can consent. Just drop them out of the study if they cry.
Posted by: babar at Apr 1, 2009 8:52:20 PM
