Supplementing Breast Milk with Formula

Many moms end up supplementing breast milk with formula at some point. Trying to figure out the best way to do it can be confusing – should you mix breast mix and formula together? Or give breast milk first, and formula only as needed? Here are three ways to supplement breast milk with formula, and the pros and cons of each.

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For the first month after my son was born, he wasn’t gaining enough weight, and I needed to supplement. I was also constantly pumping and trying to figure out when I should give him breast milk and when I should give him formula.

For example, I’d read somewhere online that I could mix it together in one bottle. I’d also read that giving formula might help my baby sleep longer at night. Or maybe I should just use all of the breast milk I had until I ran out and then give him formula?

3 Ways to Supplement with Breast Milk with Formula

Here are the different ways that I tried supplementing with formula, along with the pros and cons that I found.

Option #1: Mix breast milk and formula together in one bottle

PRO: If your baby is accustomed to breast milk, he is more likely to accept the bottle, as the flavor will be more like what he’s used to. Also, you only have to make one bottle.

CON: If your baby doesn’t finish the bottle, it will have to be thrown out an hour after he starts drinking it. (Breast milk-only bottles can be kept for the next feeding; formula bottles must be discarded an hour after the feeding begins.) Throwing away breast milk – especially when you are supplementing – is painful!

Option #2: Start baby with a breast milk bottle and follow with a formula “chaser”

With this option, you give your baby all the milk that you have available for the feeding, and then offer him formula after the breast milk bottle if he is still hungry.

PRO: No throwing away breast milk! Also – if it is important to you to minimize formula, with this option, you are only giving your baby the amount of formula that you absolutely have to.

CON: You have to prepare and wash two bottles. Also, if your baby doesn’t like the taste of formula, he might refuse the second bottle and still be slightly hungry and cranky.

Option #3: Pick one or several feeds of the day to be formula feeds and only offer formula at that feeding

PRO: It’s much simpler – only one bottle to deal with and one liquid to prepare. And again, no throwing away breast milk.

CON: If your baby doesn’t like the taste of formula, it might be difficult to get him to take this feeding. However, it’s more likely that he’ll take it since he’ll be pretty hungry (versus option #2, where he’ll already have had some pumped milk).

I generally chose option #2 until I was able to get my supply up with fenugreek.

Because I am a bit lazy, I bought some of the nursettes that they gave me in the hospital and would give him those after a feeding when I ran out of breast milk. This worked great; it was lucky for me that he didn’t mind the taste, and I still only had to prep and deal with one bottle since the nursettes were all ready to go. The only downside with these is that they are a little expensive.

Rules for Mixing with Breast Milk and Formula in the Same Bottle

If you decide to go with option #1, where you put everything in the same bottle, here are some guidelines for how to do it:

1. If you’re using formula that needs to be prepared (like powdered infant formula), mix and prepare according to the directions first, before adding it to your breast milk. Do not add the powdered formula directly to your breast milk. (This doesn’t apply if you’re using ready-to-feed formula.)
2. If you’re preparing a mixed milk bottle to feed later, chill the prepared formula before adding it to refrigerated breast milk to avoid raising the temperature of the breast milk – just like you should chill freshly pumped breast milk before combining it with milk already in the fridge. (If you’re feeding immediately, you’ll be warming the breast milk anyway, so this doesn’t apply.)
3. When feeding from a mixed bottle, you should discard milk based on the earliest time that would apply to any milk in the bottle.

You also might like:

• How to Maximize Your Pumping Sessions and Get the Most Milk Possible
• Can Breast Milk Come Back? Relactation Pumping Schedules
• How to Pump More Milk With Healthy Lactation Granola

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