Lactation Narration

The previous (2005) version of the AAP’s (American Academy of Pediatrics) Breastfeeding and the Use of Human Milk document, had the following statements about breastfeeding beyond infancy (emphasis mine):

Pediatricians and parents should be aware that exclusive breastfeeding is sufficient to support optimal growth and development for approximately the first 6 months of life, and provides continuing protection against diarrhea and respiratory tract infection. Breastfeeding should be continued for at least the first year of life and beyond for as long as mutually desired by mother and child.

There is no upper limit to the duration of breastfeeding and no evidence of psychologic or developmental harm from breastfeeding into the third year of life or longer.

This was a very supportive statement for those of us who nurse beyond infancy, and even beyond toddlerhood into the pre-school years. I have pulled out this AAP statement many times to defend myself from those who would call breastfeeding beyond infancy not just un-beneficial, but actually harmful to children.

I have also used the AAFP (American Academy of Family Physicians) statement from its 2008 position paper:

NURSING BEYOND INFANCY
As recommended by the WHO, breastfeeding should ideally continue beyond infancy, but this is not the cultural norm in the United States and requires ongoing support and encouragement. It has been estimated that a natural weaning age for humans is between two and seven years. Family physicians should be knowledgeable regarding the ongoing benefits to the child of extended breastfeeding, including continued immune protection, better social adjustment, and having a sustainable food source in times of emergency. The longer women breastfeed, the greater the decrease in their risk of breast cancer. Mothers who have immigrated from cultures in which breastfeeding beyond infancy is routine should be encouraged to continue this tradition. There is no evidence that extended breastfeeding is harmful to mother or child. Breastfeeding during a subsequent pregnancy is not unusual. If the pregnancy is normal and the mother is healthy, breastfeeding during pregnancy is the woman’s personal decision. If the child is younger than two years, the child is at increased risk of illness if weaned. Breastfeeding the nursing child after delivery of the next child (tandem nursing) may help provide a smooth transition psychologically for the older child.

and the AAFP 2007 policy statement also states:

Breastfeeding beyond the first year offers considerable benefits to both mother and child, and should continue as long as mutually desired.

The AAP has released a new and updated document today on Breastfeeding and the Use of Human Milk. The new 2012 version does not say much about extended breastfeeding, only the following:

The AAP recommends exclusive breastfeeding for about 6 months, with continuation of breastfeeding for 1 year or longer as mutually desired by mother and infant, a recommendation concurred to by the WHO and the Institute of Medicine.

Mothers should be encouraged to continue breastfeeding through the first year and beyond as more and varied complementary foods are introduced.

While this is still supportive of breastfeeding beyond infancy, I wonder why this topic was not covered as fully in this revision? Was it an oversight? I would have appreciated more on this topic from the new AAP statement, not less.

I participated in a study recently, in which the researcher was investigating the maternal cells present in breast milk. She needed fresh milk for the study, so I went to her lab to express some milk.

She provided a Medela Symphony breast pump for the mothers in the study, but I found that it didn’t really work for me to pump. Sweets is over 2.5 years old now and it’s been a year since I pumped at work. She typically only nurses 1-2 times per day, so I don’t have a lot of milk anymore, and the pump just wasn’t doing anything.

I decided to hand express instead, and I did get a little milk that way, but only about 6 mL. For reference, there are about 30 mL to an ounce, so that is really not very much milk!

The researcher let me watch as she centrifuged my milk sample, which separates the fat to the top of the sample and the cells to the bottom with the liquid portion of the milk in between. Then she removed everything except the cell pellet, washed the cells, and centrifuged them again. After the cells were washed, she looked at them on a microscope to count them. This is what we saw.

And from that little 6 mL, she was able to get 7,850,000 cells! That is 1.3 million cells per mL, which would be almost 40 million cells per oz! She had several experiments she wanted to do with the cells, and while this was enough for one experiment, it would not be enough for all of them. She encouraged me to come donate again if I was willing and able.

I went back two more times, with pretty similar results. The second time I had 6,160,600 cells in 5 ml of milk. The third time I had 9 million cells in 7 mL of milk.

Donation	Total Cells	mL	cells/mL	cells/oz
1	7,850,000	6	1,308,333	38,692,035
2	6,160,600	5	1,232,120	36,438,137
3	9,000,000	7	1,285,714	38,023,109
		Average	1,275,389	37,717,760
		Std Dev	39,142	1,157,559
		Std Err	22,598	668,317

Not too bad for 2.5 years out! Next time someone tells you that there are no benefits to breastfeeding past a certain age, don’t believe it!  Most of the mothers who donated to the study had about half as many cells per mL than I did (though of course they had more milk volume too).

So the next question is, what are all those cells?

Most of the cells in milk are mammary epithelial cells.  The research study I donated to is investigating mammary stem cells in this subset.  Total leukocyte (white blood cell) counts are reported to be 4 million/mL in colostrum and 0.1-1 million/mL in mature milk. These are comprised of about 55-60% macrophages, 30-40% neutrophils, and 5-10% lymphocytes. Of the lymphocytes, about 80% are T cells and about 5% are B cells. Of the T cells, both CD8+ (cytotoxic) T cells and CD4+ (helper) T cells were present, and most were activated memory cells.

In short, a whole variety of live cells are present in breast milk. Milk is more than just a source of food for the infant. These cells can be absorbed by the infant through the mucosal membrane of the intestine, where they continue to carry out their normal functions. (One interesting side-effect of this is that it is postulated that kidney transplant recipients who were breastfed as infants and receive a half-matched kidney donated by their mother are less likely to experience rejection than those who were not breastfed, or those who receive a half-matched kidney donated by their father.) The maternal immune cells continue to  support and influence the child’s immune system.

It is an amazing gift that I give to my child, of my own body. Truly.

There is a lot of confusion about proper breast milk storage. That is because it seems like every source is giving us conflicting information on this topic! Some moms go by “the rule of 8″: 8 hours at room temperature, 8 days in the refrigerator, 8 months in the freezer. I’ve also heard this as the rule of 6 or the rule of 10 though. Which is right? Here is a compilation of the guidelines from a variety of sources. It is interesting to note how the guidelines differ based on the interests of the source.

Let’s start with some breastfeeding advocates:

Source	Room Temp	Refrigerator	Freezer	Deep Freezer
Kellymom	10 hours	8 days	3-6 months	6-12 months
Dr. Sears	10 hours	8 days	3-4 months	6+ months
LLL	4 hours (ideal); up to 6 hours (acceptable); (Some sources use 8 hours)	72 hours (ideal); up to 8 days (acceptable)	6 months (ideal); up to 12 months (acceptable)	*

Now let’s look at the guidelines from medical sources:

Source	Room Temp	Refrigerator	Freezer	Deep Freezer
CDC	6-8 hours	5 days	3-6 months	6-12 months
ABM	6-8 hours	5 days	3-6 months	6-12 months
AAFP	6-8 hours	5 days	3-6 months	6-12 months
AAP	4 hours	48 hours	3-6 months	*

Now let’s look at the guidelines from companies who make breast pumps and accessories:

Source	Room Temp	Refrigerator	Freezer	Deep Freezer
Lansinoh	4 hours (ideal); up to 6 hours (acceptable); (Some sources use 8 hours)	72 hours (ideal); up to 8 days (acceptable)	6 months (ideal); up to 12 months (acceptable)	*
Ameda	6-10 hours	8 days	3-4 months	12 months
Medela	4-6 hours	3-8 days	6-12 months	*
Hygeia	6-8 hours	5-7 days	3-6 months	6-12 months
Simplisse	6-8 hours	5 days	3-6 months	6-12 months

And finally, let’s look at the guidelines given by formula companies:

Source	Room Temp	Refrigerator	Freezer	Deep Freezer
Enfamil	*	48 hours	3-4 months	*
Nestle/ Gerber	*	24-48 hours	up to 3 months	*
Similac	3-4 hours	5 days	*	*

I’m not going to tell you which of these are the “right” guidelines, but after seeing the commonalities and differences, you can make a more informed decision for yourself.

*Note that cells are blank where I could find no recommendation for this condition from this source

This week’s topic organized by Nursing Freedom is about the analogy between nursing in public and smoking in public. This reminds me of another way that I have used smoking as an analogy to formula feeding – in reference to personal choice and health care professionals’ support of that choice.

So, suppose that you are a smoker. Your doctor can accept the fact that you are a smoker without necessarily supporting your smoking. She can encourage you to quit, and tell you all the reasons why smoking is a health risk, but of course she can’t force you not to smoke – that’s still your decision. Should she just leave it be because telling you these things may make you feel “guilty” for smoking? After all, it’s your personal decision. But that personal decision has negative health effects, and should not be supported by your health care professionals.

Let’s also look at the way that your health care provider does talk to you about smoking. Would she say, “Smoking is the typical choice, but let’s look at the extra bonus benefits of not smoking”? Or would it be, “Not smoking is the healthy choice, and there are negative health effects of smoking”? You may think that your reasons for smoking are fine and you don’t care about the risks, but your doctor still doesn’t have to support that decision as though it were an equally healthy choice. The doctor is still going to have plenty of patients who choose to smoke despite knowing the risks. She will accept it and work with the effects of your decision, but that is not the same thing as endorsing that choice. She’s not going to tell you that it’s just fine as long as you are happy, or that since you didn’t smoke for the first X years of your life that’s good enough.

Now think about the way that health care providers talk about formula and breastfeeding. Health care providers should talk about the health risks of formula feeding (as opposed to the “benefits of breastfeeding” – breastfeeding is the biological norm), without having to worry about someone feeling guilty. Their role is to encourage healthy behaviors, not to equivocate on the issue for fear of offending someone. If you do choose to use formula, your doctor will accept your choice and work with you, but she doesn’t have to present it as an equivalent option or try to make you feel better about your choice.

Also, just because you are already using cigarettes anyway, it doesn’t mean that your doctor should give you free cigarette samples. And it seems obvious that if you’ve already decided to quit smoking, your doctor shouldn’t send you home with a few free cigarettes “just in case” you fail. But that is just what happens every day when doctors and hospitals distribute free formula samples.

You will also hear plenty of people who say things like, “Well I’ve smoked for X years and I am perfectly healthy” or “Great Aunt Bessie smoked 2 packs a day for her whole life and lived to age 95″. Will that anecdote convince the health care professional? Will you hear your doctor tell you, “Well, a whole generation of people were smokers not that long ago, and they seem to have survived it, so I guess it’s no big deal. Forget about all the studies showing the health risks – you have anecdotal evidence that says it’s fine.” I sure hope not. And yet that’s pretty much what my first pediatrician said regarding a generation who grew up on formula.

Of course I think that breastfeeding is a choice that each mother must make on her own, but that does not mean that I think that breastfeeding and formula feeding are equivalent choices. Just like I don’t think that smoking and not smoking are equivalent choices. I still believe it is your choice to make though, whether you tried to breastfeed unsuccessfully, or you just didn’t feel like breastfeeding, or whatever your situation. The point is, that medical professionals should try to encourage and support you to make healthier choices by presenting accurate information, and should not pretend that it’s just a simple choice between two equals just to make you feel better when you don’t (or even can’t) breastfeed.

A study was recently brought to my attention that basically advocates supplementing with formula within the first two weeks of birth in order to reduce likelihood of cow’s milk allergy. The first author of the study, in interviews by the press, stated his recommendation to breastfeed while “simply complementing it with cow’s milk early on.” He says, “Let Dad enjoy some midnight infant bonding, while he delivers a dose or two of cow’s milk protein.” He specifies in the conclusions of the study that “The data should not be interpreted as discouraging breastfeeding.”

This is not a study that I’d seen before, but I do find it interesting from an immunological perspective. The study essentially goes to tolerance. Basically, your immune cells need to learn “self” vs “non-self”, and tolerance is used to tell them not to attack “self”. Sometimes this gets messed up, and you end up with an autoimmune condition – essentially, your immune cells attacking some part of “self” that it should have had tolerance to. There are also plenty of “non-self” things though, that you don’t want the immune system to attack – food, pollen, a fetus… The body should therefore also be able to tell “danger” from “non-danger”. When the immune system mounts an attack on something that we consider “non-danger”, that’s typically what we call an allergy. It’s a tricky business for the immune system to learn what it should and should not attack, and immunologists are very interested in learning how it works, which is still not fully understood. If we could manipulate this system, it could lead to many medical breakthroughs in autoimmune disease, allergies, transplant medicine, and the like.

Unfortunately, we still don’t know exactly how it does work. This study is postulating that exposure to the allergen within the first two weeks of life, seems to result in a higher rate of tolerance to that allergen (in this case, cow’s milk protein). This study though, is purely observational and does not even begin to propose a mechanism for how and why this would work. Without a mechanism, one observational study is not going to be enough to influence the medical associations and public health boards to change their current recommendation of exclusive breastfeeding for at least 6 months – exclusive breastfeeding being defined as no water, juice, formula, cereal, or foods.

Some other thoughts on this study:

**The reported incidence of cow’s milk allergy (CMA) is 2-5%, yet this study only found it in 0.5% of their population. They either have a skewed demographic or they have different diagnostic criteria than other clinicians. In addition, 381 cases were reported to the researchers by the parents as CMA, but the researchers diagnosed only 66 of these as actually allergic using their criteria. If parents did not report CMA, the researchers assumed CMA was not present. Only those who reported CMA were tested for it. Also of note, this study did not find any correlation of rate of CMA with other factors previously shown to affect likelihood, including gender, type of delivery, and genetic background.

**The study purports to relate first exposure of cow’s milk protein with incidence of CMA, however the researchers excluded any formula that was given to newborns while still in the hospital (estimated to be ~70% of all Israeli babies) as inconsequential.

**The study also excludes babies who were not exposed to cow’s milk or cow’s milk formula at all within the first year. The general recommendation from medical and public health associations is to breastfeed exclusively for 6 months, followed by continued breastfeeding with the introduction of complementary foods until at least 12 months, with introduction of cow’s milk after 12 months. Therefore, all babies whose parents actually followed this advice were excluded from the study and there is no data on their rate of CMA. These babies were excluded presumably because babies typically outgrow a cow’s milk protein allergy after the first year anyway. Babies who were delayed introduction to cow’s milk until after this time are not at a disadvantage. Cow’s milk is not a necessary part of a human diet, particularly a human infant whose diet consists of human milk.

**The study found a 0.5% rate of CMA for introduction of cow’s milk protein at most time-points. The publicized result was that the rate was 10 times lower when introduced at less than 14 days. However, it is also worthy to note that the incidence was 3.5 times higher when cow’s milk protein was introduced between 3.5-6.5 months. And, as mentioned above, the rate for those who were not exposed to cow’s milk protein until after 12 months was not given because these infants were excluded from the study.

**The study measures the first (non-hospital) exposure to cow’s milk protein in days, but it does so through parental interview at two-month intervals. Recall rate down to the exact day for introduction of cow’s milk protein from an interview up to two months later seems prone to inaccuracy given that parents were not asked to keep a daily diary. Though the study calls itself prospective because subjects were enrolled at birth, the methodology for data collection was retrospective.

**The study did report on dairy product consumption by the mother, however less than 1% of mothers did not consume dairy. Of note, all of the mothers who did not consume dairy had babies who did not have CMA, but the numbers were very small and there was no statistical significance.

**The study was funded by the Israel Dairy Board, a potential conflict of interest. Note that the conclusions of the study are to begin supplementing breastfeeding with formula made from cow’s milk within the first two weeks of birth, which would be of financial benefit to the Dairy Board.

My personal conclusions: Benefits of introducing cow’s milk formula within the first 2 weeks may include reducing the likelihood of cow’s milk allergy by inducing early tolerance. Costs of introducing cow’s milk formula though are loss of exclusive breastfeeding (and associated health implications) and increased likelihood of earlier weaning in general. Cow’s milk allergy is typically outgrown within the first year anyway, and delay of introduction of cow’s milk or cow’s milk formula until after 12 months also reduces the likelihood of cow’s milk allergy while also avoiding the other risks inherent in formula feeding. Introduction of cow’s milk formula between 3.5-6.5 months may be the worst scenario with respect to cow’s milk allergy. Even if reduced risk of cow’s milk allergy was only to be achieved through early use of formula, I do not think that this would be worth risking the other health implications of not exclusively breastfeeding.

At our 2 month well-child visit, our pediatrician likes to advise vitamin drops for the baby, specifically for vitamin D supplementation. I didn’t give Munchkin the vitamin drops more than a couple times though, because the popular knowledge in my breastfeeding-savvy group of friends said that we would get enough vitamin D from the sun.  When Sweets was a baby, I revisited the issue and found new information. This time I concluded that in general we probably don’t get enough sun (“we” meaning Sweets and myself as well as “we” in our general culture) to make enough vitamin D as we are meant to by nature. I know that I always use sun screen on myself and I keep Sweets in the shade and put a hat on her and such. New research is finding that we should have even more vitamin D than was previously thought too. But I was still reluctant to give her the vitamins because a) they taste bad, b) they make a mess and stain when she spits them out, c) I feel like she should be able to get everything she needs from breastfeeding, and d) I don’t like having to buy a product made by Enfamil.

So I decided I wanted to supplement myself enough to have it pass though my milk instead. My pediatrician told me that it wasn’t possible for me to supplement myself enough that it would transfer a high enough amount through my milk. That seemed wrong to me, so I dug deeper. I take a prenatal vitamin with 400 units of vitamin D, and I initially thought that should be enough. I had bloodwork done to test my levels and they were 48 in my blood – which is fine for just myself, but not enough to be sufficient for the baby to get from my milk (blood levels are the same as milk, so she’d only be taking in 48 units). The recommended daily dose for infants is 200 units, so I needed to get my milk levels up that high too. I emailed with Dr. Jack Newman and asked his recommendation. Here is his reply:

Actually, there are studies that show that if you take 4000 Units of vitamin D (another study 6400 Units), a day, the baby can get enough vitamin D in breastmilk to prevent rickets. This is relatively new information.

If you are vitamin D sufficient, the baby is born with a liver full of vitamin D which probably lasts him for at least two months.

And you can get plenty of vitamin D from being outside. The baby doesn’t have to be out in full sun in summer to get it. Late in the afternoon for a few minutes a day is fine.

4000-6400 units is WAY more than the 400 units that are in my multivitamin. So now in addition to my multivitamin, I also take a 5000 unit vitamin D supplement, giving me a total of 5400 units per day. That way my own levels will be high enough for Sweets to get enough vitamin D through my milk and I don’t need to supplement her at all.

I showed the research to my pediatrician, who found it very interesting and concluded that the reason that this isn’t routinely advised is because the published toxicity levels for vitamin D are only 2000 units and they can’t advocate taking more than that. My research leads me to believe that the published toxicity levels are too restrictive, so I am willing to take the risk.