Hero Image
profile picture of Jessica Shortall
Jessica Shortall
Contributing Writer

Building a Breast Milk Stash Before You Go Back To Work

Meet Jessica Shortall, a working mom with a career dedicated to the intersection of business and doing good. As the former Director of Giving for TOMS Shoes, she literally circumnavigated the globe with a breast pump.  Pre-order her upcoming book by Abrams, “Work. Pump. Repeat: The New Mom’s Guide to Breastfeeding and Going Back to Work,” out Sept. 8.

I’ve been blogging about breastfeeding and working for a few years now, and I’ve noticed that the most common Google search that has readers finding my little outpost is a search term along the lines of “help I’m going back to work and I’m freaking out about how to build up a stash of breast milk in the freezer.” Or something like that. This is one of the first big stressors for the working, pumping mama, because with a typical (crappy) American maternity leave, you have to start thinking about it so early.

So how on earth can you store up enough milk to leave with your baby’s caregiver?

After you’ve learned how to pump, you have to get on a regular schedule of pumping and saving breast milk if you want to build up a stash. You have likely heard a lot about the supply and demand aspect of breastfeeding — that supposedly perfect cycle of your body making as much milk as your baby needs. This might make you wonder how you will ever get any additional milk to save for when you go back to work. But it is entirely possible, assuming you have a pretty normal milk supply. (If you have a low supply and/or are already supplementing with formula, you will have to work harder to store up milk, and you are likely looking at your caregiver doing the supplementing during the day. And you are still an awesome mom.)


There are two relatively easy times of day to get that extra milk while you’re still on maternity leave (assuming you got one!):

  1. Immediately after the morning (approximately 7 a.m.) feeding
  2. While baby is sleeping (once she’s sleeping longer through the night)

Let’s focus on no. 1, since no. 2 is much less predictable, and you ought to be asleep at night anyway. Most women’s milk is more abundant in the morning. And by kicking the day off with some additional demand, pumping in the morning offers the benefit of setting you up for a more milk-productive day. Feed and burp your baby, then set her up somewhere comfortable, and sit down to pump. In the first few days or even weeks you might get very little milk when you do this, and you will think I am either a liar or an idiot. But stick with it, and don’t let it freak you out, and you will see the volume go up over time.

The milk you pump can go straight into a freezer bag, or into the fridge until you have enough to fill a freezer bag. Label these bags with the date. If you want to be super organized, freeze them lying flat on their sides to make little flat bricks, then stack the bricks upright in a shoebox in the freezer. Oldest milk (by date) goes in the front, and newest milk goes in the back. Then you can pull individual bricks out to thaw in the fridge (always thaw inside Ziploc bag, in case of leaks!).

Within a few weeks, you will start to have a nice little supply. (But please, please take note: you do not have to do this additional pumping every single day. Some days you will be tired. Some days your baby will need you, or you’ll just plain not feel like it. Give yourself a break. It’s gonna be ok.)

This now brings us to the “how much?” question.

The obvious answer is that you need enough milk to get your baby through a single workday of feedings. This is based on the premise that you will pump enough on your first day back at work to replenish your at-home supply. But taking into consideration the stress and emotion of the first day back, it’s best to have a bigger stash at home. Let’s call that three work days as a goal. If, while still on leave, you are directly nursing for most of your baby’s feedings (rather than bottle feeding formula or expressed milk), you might have no idea how many ounces of milk your baby eats during a typical day. So you can try a whole day of bottle feeding your expressed milk, and arrive at a very clear number of what your baby ate on that day.

But I think the more accurate, and less time-consuming method is to go with pediatricians’ best estimate of what a normal baby eats: on average, 26 ounces per day. Every baby is different, and this is an average, but that’s ok; we’re just trying to get to a reasonable number to shoot for. Either way, divide your 24-hour figure by the number of feedings your baby is doing per day (probably between six and eight for a 2- to 4-month-old baby), and figure out how many feedings you will miss by being away at work. There’s your magic number for a single workday.

For example, let’s assume:

  • Baby eats 26 ounces per day and is finishing six feedings in a 24-hour period when you go back to work (that’s 4+ ounces per feeding).
  • She eats on a semi-regular schedule of 7 a.m., 10 a.m., 1 p.m., 4 p.m., 7 p.m., and a “dream feed” at 9:30 p.m.
  • This means that in a 9 a.m. to 6 p.m. workday you will miss three feedings.
  • Therefore you need to leave her caregiver with four (and a bit) times three = 13 ounces of breast milk.
  • Shoot for 15 ounces to be safe.
  • So, for a three-day stash, you need 45 ounces of milk.

45 ounces looks daunting on paper, but it is doable if you start early. Even if you were to “bank” only 2 ounces per day, within about three weeks you’d hit your goal. And many women will get much more than a couple of ounces out of that morning pumping session as time goes on. (If you have a short maternity leave or no leave at all, don’t panic. A single day’s worth of breast milk is great. So is supplementing with formula and building up that stash of breastmilk more slowly. It’s gonna be ok.)

If you have business travel, you will have some additional decision-making to do. Being away from your baby for one or more overnight requires quite a lot of milk in the freezer if you don’t want to supplement. Go back to that 26 ounce average for a 24-hour period. So a three-day business trip would use up something in the neighborhood of 78 ounces of milk. (Of course, you will be pumping on the road, and can bring that milk back with you to replenish - more on flying home with milk here.)

So, are we good? You’re going to take this one day at a time. You’re not going to panic when your first pumping session produces a few measly drops of milk. You’re going to cut yourself a break. And you’re going to be just fine.

Questions? Fire away in the comments,  join me on Facebookand ask a question there, or grab my survival guide book, Work. Pump. Repeat., when it comes out in September 2015.