Mohrbacher’s Magic Number

If a multinational company developed a product that was a nutritionally balanced and delicious food, a wonder drug that both prevented and treated disease, cost almost nothing to produce and could be delivered in quantities controlled by the consumers’ needs, the very announcement of their find would send their shares rocketing to the top of the stock market. The scientists who developed the product would win prizes and the wealth and influence of everyone involved would increase dramatically. Women have been producing such a miraculous substance, breast milk, since the beginning of human existence…
– Gabrielle Palmer, in The Politics of Breastfeeding (London: Pinter & Martin, 2011.)

Breastmilk is pretty magical stuff. Sometimes, though, it’s hard to figure out how the process works. At the store, there’s what seems like an unlimited supply of foodstuffs. As long as our money holds out, we can have as much as we want.

When we grow our own food, our understanding changes. There are rules: You can’t have fresh asparagus out of your garden in December. The radishes will take a few weeks, no matter how anxious you are for them to grow. And you can’t eat that winter squash off the vine in June, it’s just not done yet!

Breast milk production has some rules too, based on the basic facts of breastfeeding life. For example, you’ve got to put the baby to breast to make milk. Many milk-making problems start with a tough birth and a tough start to breastfeeding. That’s why you keep your baby close at first (I like “breastfeeding is a womb with a view” to remember this), and basically nurse your brains out in the first days to jump start your supply.

How much milk am I making?

By the time your baby is a month old, you are making about 24 ounces of milk every day. Unlike formula fed babies (who take more and more formula as they grow), the intake of a breastfed babies stays remarkably constant – by six months, most moms are making another four ounces of milk (a total of just about 28 ounces – even if you’ve got one of those Sumo Babies!). That means, if breastfeeding is going nicely at one month, you’re not going to need to worry about increasing your supply every week to keep up with your baby’s needs.

That paragraph has a lot of numbers so let me say it again.

  • Most breastfed babies are growing like crazy on 24-28 ounces of breast milk a day. Even when they are 5-1/2 months old.

Why does my baby eat so often?

You may know people whose formula-fed babies eat eight ounces of milk every four hours, then sleeping a longer stretch at night. It’s almost a boast – “My baby is eating over forty ounces of formula!” (We do not think about the price of formula when we hear this….but we probably should.)

Most breastfed babies are eating more often. If we’re going back to work, we think about those eight ounce bottles of formula. And we think about how much we can pump at a time. Panic ensues.

But breast milk is a very different fluid from formula. Babies need more and more formula to get the nutrients they need. Breast milk changes as your baby grows, and breast milk is packed – right from the very beginning – with loads and loads of nutrients that your baby can’t even begin to use yet! (That’s why you get those poop explosions at the beginning of life.)

Kirsten Berggren, author of Working without Weaning and owner of says, “The only person who really knows how much milk your baby needs – is your baby. Problem is, she’s not talking. So you need to set things up so that she can communicate how much she needs. The best way to do this is to send milk in a number of small bottles. For the first few days, 2 oz bottles are fine. If your baby drinks them very quickly and always takes another one, then you can gradually increase the amount in the bottles. Ask your care provider to keep careful records of all of her feeding times and amounts for the first few days so that you can adjust the size of the bottles you’re sending.”

Be sure, too, that you have a talk with your childcare provider about the way your baby likes to feed. If she is used to formula fed babies, she may be used to encouraging the baby to take more at every feeding. With breastfeeding, we are all about letting the baby make that decision. And we don’t want to stretch the baby’s stomach so that they are constantly uncomfortable.

Your baby may take 9 ounces in your eight hour workday – or she may take 15 ounces. Plan to pump at the times of day your baby usually nurses. (How will you know this? Take a few days before you return to work. Keep a feeding diary like you did at the beginning. Aren’t you glad you know now about those little comfort nips versus the big long feeds?)
After a few days, you will know what Nancy Mohrbacher IBCLC (author of Breastfeeding Made Simple and Breastfeeding Answers Made Simple) calls your Magic Number. Plan to pump enough at work so that your breasts know they should continue to make milk, and your baby gets enough at childcare. Otherwise you may end up with a baby who needs to nurse more often at night while you are back at work, just to make up for the milk she didn’t get during the day. By the way, check out Nancy’s blog.

Every baby is different – and so is every mom

We often focus on how much our babies are eating, and worry that they are eating too often. But there are also moms who worry because their babies are going a long time between feeds. That’s another facet of the Magic Number.
Each mom has a different breast storage capacity. I have know moms who always pump 1-1/2 or 2 ounces of milk, no matter how much Mother’s Milk Tea they drink. (By the way, Peter Hartmann and Tom Hale’s study on milk production found that with the world’s most efficient pump, the study moms regularly pumped one ounce per hour – that’s 24 ounces for the day.) I have also known moms whose babies would only eat every six hours. Not many, but a few! The first time I ran into this problem, I was flummoxed. The baby was thriving and literally glowing and happy. The mom was a wreck – why wasn’t the baby eating? She had large breasts – and when she pumped, she could easily pump over eight ounces of milk. Once morning she pumped twelve ounces!

To read more about this, see the report by Peter Hartmann’s Australian lactation team.

Remember that the size of your breasts doesn’t make all the difference. Fat stores account for the biggest difference in our breast size. But the milk-making equipment inside is different for all of us. (And second time moms regularly make 20% more milk because they “build” more milk-making capacity during the second pregnancy!)

The lactation field continue to be a fascinating source of research. Who would ever guess that mothers, babies and that magical milk could be so interesting and so much fun! Take a few minutes to read Nancy Mohrbacher’s Magic Number article.

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