Thursday, October 3, 2013

White elephants in the freezer: The pros and cons of breastmilk stashes

Back in the glory days when Baby Seal was tiny, my "freezer stash" fluctuated, but basically consisted of two to three plastic containers stuffed at crazy angles around the frozen peas. For one thing, I had the tiniest freezer known to man and needed the space for ice cream healthy homemade casseroles and soups. When were you supposed to find time to pump, in between nursing all day long? In any case, I was lucky enough to work freelance at home. I doubt I would have "stashed" at all had it not been for a vague feeling that this was something you were Supposed To Do when you are breastfeeding. My due date club was full of people talking about having dozens or hundreds of ounces in the freezer. Stashing seemed like part of being a proper organized mother--you know, the kind who irons baby clothes and puts her name on the daycare waiting list at five weeks' gestation.

The freezer culture
The "freezer stash" culture seems to have started among mothers who work outside the home. The idea is: since most mothers find that a few pumping breaks stolen out of the working day just aren't enough to keep up with their babies' needs, you pump during your maternity leave to create a "bank" of frozen milk that you can draw on little by little once you're back at work. Once working, you top-up your stash by pumping at the weekends--or even late in the evening, after the baby is (finally!) in bed. However, in the US in particular, freezer stashes have recently started to become common even among stay-at-home-mothers. This seems a bit odd at first glance--does an evening-out a couple of times a week really require a freezerfull of breastmilk?--but the rationale is that you might be forced to wean for medical reasons, you milk could dry up or (gulp) you could be knocked down by a car and killed. Increased milk-sharing opportunities have perhaps added to the feeling that everyone should be creating a freezer stash ("After all, even if you never use it, someone else will always be able to!"). It's not uncommon these days to hear of women putting hundreds or thousands of ounces into the freezer; many are generous donors, helping out other mothers and hospitalized infants.

The idea seems to be that a freezer stash helps you avoid using any formula, and is strongly connected with modern breastfeeding culture's focus on exclusive breastfeeding and avoiding formula completely. That said, wanting to avoid formula isn't always about formula being inherently dangerous. Formula companies aren't very nice organizations and many people don't like the idea of giving them money. Then there is the "My baby may not accept formula if I try it later on" thing. There is the "I prefer not to do dairy products, and soy makes me nervous" thing. Finally, some mothers also envisage this as a way of getting extra breastmilky goodies into their child--they imagine a toddler drinking thawed EBM in a sippy or mixed with cow's milk.

Beware of the scary freezer...
The dark side of the freezer (cue ominous music...)
Conversely, stashing has some downsides too. What you might call "The Dark Side of the Freezer" (and no, I'm not talking about those ancient tupperware containers containing brown goo of unknown origin, or the ice-cubes that taste of stale fish when you add them to your gin and tonic).

- Frozen breastmilk is significantly inferior to the fresh stuff 
The general assumption is that "even frozen breastmilk is always far, far better than formula." But the evidence is actually quite mixed. Frozen breastmilk has about the same amounts of fat, calories, sugar, protein and elements such as zinc as fresh, and many of its impressive immunological components such as lactoferrin, lysozone and IgA also stand up well to freezing. Freezing does, however, destroy cellular activity and antioxidant activity are greatly reduce to. (That said, frozen breastmilk still has more antioxidant activity than formula).

However, the evidence about decreases in vitamins is less positive. A 1983 study found that "Freezing and frozen storage did not significantly affect the levels of biotin, niacin, and folic acid." But in a 2004 meta-analysis (Ezz El Din et al), Vitamin C in milk was reduced by 56.9%  by one week of freezing, Vitamin A by 48.1% and Vitamin E by 28.8%, echoing a 2001 study (Buss et al) which found that Vitamin C decreased to 63% of the starting values after one month and 38% after two months of freezing; there was massive variation, with one sample having 97% of the Vitamin C it started off with, and another, zero. Confusingly, the findings of another study (Bank et al) indicated that breastmilk frozen for three months would provide a baby's recommended allowance of Vitamin C--but not of folic acid.

This doesn't mean frozen breastmilk risks giving your baby malnutrition; babies supplemented with bottles of the stuff do just fine. But then, well, babies supplemented with bottles of formula seem to do fine too. The question is, if frozen EBM is better than formula, then by how much of a margin is it better? Because this margin has to be weighed up against the substantial amounts of time and energy that go into creating large stashes.

- What are the benefits of avoiding all formula?
The freezer stash tends to be intertwined with anxiety about using any formula at all--a sort of icy buffer zone protecting your baby against the Great White Peril. Now, the PROBIT study (still the closest thing we have to a randomized controlled study of breastfeeding versus formula feeding) suggests that exclusive breastfeeding for the first few months confers some health benefits; however, the study looked at mothers who were mainly feeding from the breast, and it's not clear whether these benefits still apply when we are talking about milk that's been pumped, containerized, frozen (and sometimes scalded and cooled as well), frozen, thawed, transported and fed in a bottle.

And the calculation of the benefits must surely shift a bit once a baby starts solids at around 4-6 months. Much of the rationale for exclusive breastfeeding rests upon the theory of the virgin gut (=your baby's insides become irreversibly contaminated once you give a taste of anything except breastmilk); but even if you accept the virgin gut theory as fact, once you've started giving food your baby's virgin gut has been deflowered and taken round the block a few times--they are already having things that aren't breastmilk. If one is giving other dairy products like yoghurt, is there any particular reason not to add a little formula as well if today's pumping fell short of the required quota? I have looked and looked, and have not been able to find any evidence of negative health-related consequences of giving some formula to a baby who is already taking solids. I guess we all feel differently about these things, but... once I started giving Baby Seal solid foods, the "milk question" suddenly felt very different. All of a sudden, formula was just another food--and it was damn useful for mixing with her cereal.

- Your stash might turn out to be unusable (I call these "White Elephant stashes")
Every due date club has at least one mother who pumps away creating a big stash... only to discover her baby won't drink it when thawed because it tastes fishy, soapy or metallic. Some women have high levels of lipase (an enzyme which breaks down fat) in their milk, causing it to develop a strange taste when frozen. You can prevent this flavor by scalding the milk before freezing; unfortunately, most women don't think to test for lipase issues before they start stashing and therefore have no idea of the problem until they already have a freezer full of funky tasting milk. Scalding the milk after thawing makes no difference, by the way.

But even if you don't have lipase issues, babies used to fresh breastmilk often refuse to drink thawed frozen milk because it doesn't taste quite right--just as adults used to regular milk often wrinkle their noses at UHT. Other babies start refusing such milk as they get older. To add insult to injury, some of them are quite happy to drink formula instead. Finally, if you discover after you've built up a big stash that your baby's digestive issues are connected to allergens in your diet (dairy, wheat etc.), your stash is useless unless you can donate it to someone.

- Your stash might be destroyed by a freezer breakdown, power cut or a freezer door accidentally left open
Hours and hours and hours of hard work literally down the drain. This happens All.The.Time.

- Going mad with the pump can jeapordize your current breastfeeding
One well-known problem is that pumping heavily in the first few weeks can lead to oversupply and engorgement--yet women seeking to build freezer stashes are often advised to start pumping just days after giving birth.

- Stashing costs time, effort and emotional energy
Stashing is not just about the pumping itself. It's also about assembling equipment, cleaning and sterilizing, labelling and dating containers, defrosting your milk, stocktaking, organizing and rotating your stash, and doing fiddly things like mixing frozen milk with fresh in various ratios to train your baby to drink the frozen stuff. If you have lipase issues, you'll also need to scald and cool the milk before freezing. Time spent doing this is time which is not being spent taking a stroller walk in the fresh air, rolling around on the floor with your baby, enjoying a glass of wine and a trashy magazine, having a hot shower, chatting with your partner, catching up on sleep, or spending some time with an older child. To misquote Hanna Rosin, "A freezer stash is only free if your time is worth nothing."

You have to feel a bit sorry for American breastfeeders who work outside the home. Most of them get kicked out of hospital when their contractions have barely died away and are expected back at the workplace after a few weeks. And now there's this increasing expectation that they ought be spending a not-insignificant chunk of their brief maternity leaves plastered to the pump--right when they are trying to recover from childbirth and the shock of caring for a newborn. Breastfeeding is sold to women as being an emotionally rewarding experience--but where's the emotional reward in spending your free time trying to squeeze in extra pumping sessions, when you could be enjoying your baby or having a hot bath (or a cold beer)?

- Freezer stashing can become competitive, obsessive and compulsive
With modern, super-efficient double electric pumps, some women put very large amounts of milk into the freezer.
"I have about 1,000 oz and have donated 3,200 oz to other mom's. [My baby] is 14 weeks old. I was pumping a lot when she was in the NICU and then when I was still home with her I pumped after each nursing session for 20 minutes. I've been back to work for two months now. I pump before work, three times at work and once before bed. I pump between 45-55 oz per day and [my baby] only eats 8 oz while I'm at work."
Impressive though these amounts are, only a minority of women with particularly strong supplies are ever going to be able to pump and store that much milk. But when all these big figures are being quoted, before you know it everyone else is peering into their freezers and wondering if they should start trying to fit in a few more pumping sessions--especially when all the talk seems to imply that not having a stash is a really scary situation that actually places your baby in peril.

A lot of stash builders refer to themselves as "hoarders"; this is a joke, of course, but the banter does seem to be cover some genuine anxiety:
"I have a deep freeze just for milk.  I worry each pump may be my last.  I eat oats every morning and gallons of milk.  My lo will be six months.  I have donated over 5000 oz to a mom. I watch my milk drive away and then i worry i may need it for an unidentified issue. I have over 3000 frozen. I make 80 oz a day and I still worry. I need help." 
"I just had my 3rd three weeks ago and have 1,000 oz in my deep freezer. I need to re-apply to donate but, I have to go back to work full time in 4 weeks and I get nervous I won't have enough. I call it a sick obsession! I don't LIKE pumping but, if I don't do it after every feeding I get paranoid I'm going to loose my supply. I'm a bit OCD when it comes to pumping."
Obviously these are extreme cases, but it's common for freezer stashing mothers to express ambiguous attitudes towards their stashes. (See this discussion at Mothers in Medicine, for example.) Some mothers find themselves inexplicably reluctant to actually use the milk they've stashed and feel increasingly anxious as the stock dwindles. They may (like this mother) find themselves grilling their childcare providers about the amounts they've used and pressuring them to use as little as possible, even when there are still tons of milk in the freezer. Some eventually end up with gallons of unused milk that's beyond its use-by date. Others start feeling irritated if their baby doesn't finish every bottle because of the waste, or try to persuade babies to swallow milk that tastes and smells foul because they can't face the thought of throwing it away.

Of course the problem here doesn't lie with the mothers themselves; it lies in the fact that when lactation is turned into a numbers game (the number of ounces you express, the number of pumping sessions, the number of minutes you are allowed for pumping breaks, the number of containers in the freezer, the number of months they've been sitting in there), it's really easy for even the most level-headed mother to become a bit obsessive--especially when you add in the inevitable post-partum craziness and sleep deprivation, and the not-terribly-subtle scaremongering about formula that we see in mothers' groups.

Keeping the White Elephants at bay!
I would recommend that anyone thinking of creating a massive stash rule out potential issues first, before they start to pump, to avoid the frustration of a "White Elephant stash."
- If your baby seems to have digestive issues/colic, hold off on stash building until you have ruled out
Just say no to White Elephant stashes!
the possibility of allergens in your milk.
- Check whether you have lipase issues; if you do you will need to scald all your milk (see here and here).
- Maintain your freezer by using a freezer thermometer and not overstocking (I now blush to think how clueless I have been in this respect).
- Have a backup plan in case the freezer fails. And stick a SHUT THE DOOR note on the door!
-Find whether you actually meet the requirements to donate milk.
-Get your baby used to the flavor of frozen milk early on.

Conversely, employed mothers who don't want to create big freezer stashes need to be okay with using some formula. (Otherwise, they are just exchanging the stress of maternity-leave stashing, for the stress of "Help, help! It's late at night, my baby's screaming, and I need to pump because today I didn't pump enough milk for tomorrow's daycare...") At-home mothers who don't want to stash should remember that things like sudden hospitalization can prevent breastfeeding; better to keep some formula in the house, make sure that one's partner knows how to prepare formula properly, and introduce a little formula early on so that the baby will accept the flavor.

Relishing the experience or shouldering a burden?
I hope this post doesn't come across as excessively negative about freezer stashing. My intention, rather, was to try and redress the balance a bit. There is a lot of talk about big freezer stashes on breastfeeding fora, and many women find them very useful and beneficial; some are also incredibly generous, donating milk to other mothers and to babies in hospitals. But we should also find room to talk about not stashing (and minimal stashing) too, and the benefits and conveniences that that can bring.

Creating a stash is an option, not something breastfeeding mothers have to do. No, even if they are employed full-time.... as long they are content with doing some formula as well. On breastfeeding fora, "having to use formula" often seems to be seen as a sign of failure or disorganization. But it's also possible to embrace such an approach as a conscious and deliberate choice: as an approach that seeks to maximize time spent with your baby, and to make breastfeeding as enjoyable as possible--a delicious experience to be relished rather than a burden to be shouldered.

The final point I'd like to end with is this: When we are comparing expressed breast milk and formula, we can't limit our conversation to what's actually in the bottle. We have to look at the wider context of how it actually got there and how much maternal time, labor and stress went into it. Womens' needs for free time, relaxation, sleep and enjoying motherhood need to be part of the discussion too.  

Freezing milk
Tips for refrigerator freezers
ABM Clinical Protocol #8: Human Milk Storage Information for Home Use for Full-Term Infants

Lipase issues
The lipase mini-saga from The Adequate Mother

Frozen milk vs fresh
Effect of storage on breast milk antioxidant activity Hanna et al, Archives of Disease in Childhood. Fetal and Neonatal Edition, 2004
Effect of storage time and temperature on folacin and vitamin C levels in term and preterm human milk Bank et al, The American Journal of Clinical Nutrition, 1985
Is stored expressed breast milk an alternative for working Egyptian mothers?   Ezz Al Din et al, Eastern Mediterranean Health Journal, 2004
The effect of processing and storage on key enzymes, B vitamins, and lipids of mature human milk. I. Evaluation of fresh samples and effects of freezing and frozen storage Friend et al, Pediatric Research 1983

Inadvertent Booby Traps from Nursing Freedom: Some interesting discussion about the necessity of freezer stashes

In closing
Trying and Failing to Control Everything and How it Led to Happiness: I love this story!


  1. I definitely have lipase issues - sometimes my milk smells metallic even when I am pumping it or feeding baby the more direct way. But the baby has never ever complained about the taste of fresh, refrigerated, or frozen, and she's six months old. So I don't know that I believe you will HAVE to scald if you have lipase issues. Aside from that quibble, though, I think this was a great post, highlighting the weird competitive hoarding that seems to overtake some women when saving milk. It surely doesn't help when the W art of B suggests that probably you should consider part time work rather than formula, since maybe once you factor in gas, tolls, and clothes, you probably don't make enough money to justify working. No wonder some women engage in competitive bf, they feel guilty they want or need to go back to work and must prove they are still loving mothers by collecting evidence of their commitment to "breast is best."

  2. I didn't like TWAOB either--I've no idea why it's so damn popular.

    Regarding the lipase issue--actually, you are quite right, it seems to be one of those things that depends on the baby; I've heard some babies will swallow lipase-y milk without complaint, and if they will do so, no need to scald the milk, as the lipase levels don't do the baby any harm in themselves. One thing I didn't cover in the post is that scalding milk further reduces the nutritional and immunological benefits of the milk. If mothers can get away with not scalding, so much the better. Perhaps the best advice of all would be "Create two batches, scald one, don't scald the other, taste them alongside, AND THEN offer them both to the baby... if one tastes fishy BUT the baby seems to be okay with it, you don't need to scald the milk (hooray!)."

  3. I think there's another element that can be considered: not worrying about it after 6 months! Dr Jack Newman is of the opinion that no baby needs formula after 6 months anyway, as they can be given a sufficient diet through solids at that stage. I felt a bit odd at this advice (we did baby led weaning for solids and my little one was certainly not eating much at 6 months) but if you're doing purées in line with current guidelines (ie everything and anything from 6 months - don't wait unless there's a history of allergies) it does make some sense. Certainly the idea of meat and veg puréed rather than high fructose corn syrup is appealing.

    I think it's like the idea of EBM in sippy cups. I thought I'd be that mum, expressing after 12 months but not feeding because that's just gross. Of course, now we're still breastfeeding at almost 15 months old and I have no plans to stop. Plus, once I realised my open system Medela Swing might have mould in it, I couldn't be bothered pumping at all. (I pumped for a whole month when my son was 4 months so I could give him a bottle with reflux meds. It made zip difference so I stopped).

    I do think that advising mums to have formula on hand and give some to baby so they will accept it is faulty though. If its an emergency, it's an emergency and the baby probably will eat. I say that as one who bought 500ml of ready prepared liquid newborn formula and typed up instructions for my husband on how to cup or syringe feed (as we had no bottles at the time). I did that when my son was 6 weeks old and I realised if I did get hit by a bus that my husband wouldn't have a clue what to do (never having worried about it before) and I wanted to buy him some time to find out from a nurse how to feed a baby if I wasn't going to be around. I was pleased to throw it out when I found it in the cupboard months later. Anyway my point was that that's a known booby trap (I love that description - hate that Best for Babes trademarked it) and should only be encouraged for true emergencies. Just like anyone relying on formula should have formula and safe water stockpiled in case of emergency.

    (Sorry for the novel)

  4. I like used the ready-to-feed liquid formula too--I used it for mixing cereal when I was on visit in the UK, but sadly, this is not available in Japan so once I was back here I pumped if I wanted to mix her cereal with anything; making up a load of powdered formula just for cereal seemed so much hassle. I did have a tin of powdered formula and had a go at giving Baby Seal some in a cup at around 7mo--I thought it might fill her tummy up a bit before bedtime--but she wouldn't really swallow more than a tiny amount. Oh well.

    Re: using food instead of milk after 6mo of age: my understanding is that the main source of nourishment until the baby is close to 12mo should be breastmilk or formula, especially since most babies take some time to increase their solid food intake. I know Jack Newman argues that babies can be given cow's milk plus solids after 6mo, but honestly, I think he says this because he really really really doesn't want mothers to use formula or contribute to formula company revenues. Overreliance on cow's milk at too early an age can cause nutritional imbalances, so I think if a WOH mother wants to pump less, she needs to be OK with using formula to make up the difference.

  5. I wrote something similar in December - One point I think is overlooked is that if you're giving milk from a freezer stash - just as if you were giving formula - to supplement what you're pumping, you're upsetting that supply-and-demand balance. If your baby is used to taking in 18 ounces when you're away at work and you "only" pump a (very common and reasonable) 12 ounces, you'll likely never catch up with that. Pumping output gradually decreases, and I consider it a best practice to feed the baby about as much as you pump each day (subject to some individual fluctuations, of course).

    For this reason, I disagree that if you don't want a stash you have to be okay with giving formula. Babies can drink what you pump. You might need to use formula in those cases when you have a baby under six months old who hasn't started solids and you forgot your pumped milk at work or something of that sort, but there's also no rule that a stash needs to be huge. Really, the problem isn't the idea of freezer stashes, period, but enormous freezer stashes. No one needs 100 ounces by the time they return to work.

  6. Hi Tipper. Thanks for your comment. I think I didn't express myself really clearly in my post--my meaning was not so much "Women who WOH and do not have freezer stashes invariably need to use formula" but more "They may need to use formula, so they should be prepared." The reality is that while simply pumping the next day's output "fresh" each and every day may be possible for some women, for a lot of women it is just not possible, at least not all the time. Women vary in terms of how well they respond to the pump, there are limits to how many pumping breaks one can get even at an accommodating workplace, and then there is the possibility of getting to work and realizing you've forgotten your pump (or getting home and realizing your bottles of milk are in the workplace freezer). If a woman is really really against using formula at all but does not have a freezer stash, she risks getting into a really stressful situation (fanatically counting every ml she pumps, interrogating the childcare provider about every last bottle, trying to fit in extra pumping sessions at ungodly times of the evening or night etc.). I've seen some women get into a right state this way.

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  8. I'm a mother who has fed my daughter only fresh bm since she was 10 weeks old and have never worried big about my supple I do pump 5 times a day when she was younger 3 times at work in a 8 hour shift and once in the morning and right on my commute back to work I do have a freezer stash that I have never used and donated to other babies my body responds well to my pump and I've always kept up with my daughters need I believe every baby is different and fed is always best my daughter hasn't really liked my frozen breastmilk either but took the frozen milk fine at one and a half months

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