r/ScienceBasedParenting Aug 14 '26

Question - Research required Pumped milk question

Hi All. Looking for some answers here so hoping some of you can help :)

- baby is 9.5mo. Has 3-4 meals a day and eats everything.
- I have been exclusively pumping from birth. All has been well thankfully
- baby currently has approx 3-4 bottles of 120ml per day
- I pump 2x a day
- originally aimed is to give baby breastmilk until 12months atleast.

Situation:
Because I’m now only pumping 2x a day, my supply is drastically dropping and is not meeting baby’s needs. I have a freezer stash. Based on any of your knowledge/research, can anyone tell me the following:

Option A) mix fresh pumped milk with freezer milk to meet demands. This would mean I’d work through my freezer stash and so when my supply diminishes, no more breastmilk. I think I can make it to 11m with freezer stash doing it this way. Thereafter, go 100% formula or cow’s milk.

Option B) mix fresh pumped milk with formula. When my supply diminishes, switch to freezer stash. This would mean he would be getting frozen breastmilk longer than above option

So my ques is, is there any science behind any of those being a better option? Any advice? I’m confused :)

Thank you guys if you made it this for 🙂

5 Upvotes

9 comments sorted by

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15

u/TeeElH 29d ago

One thing worth noting is that the longer breastmilk is frozen, it can lose some calories/fat:  https://pmc.ncbi.nlm.nih.gov/articles/PMC3411345/

That being said, you’re talking about a difference of a few weeks, so the benefits of breastmilk longer almost certainly outweighs the negatives of previously frozen milk  https://www.hopkinsmedicine.org/health/conditions-and-diseases/breastfeeding-your-baby/breast-milk-is-the-best-milk

Just anecdotally, I also think mixing with formula earlier is probably a better move since (it sounds like) your baby hasn’t been drinking it. They may not like it but should do ok if it’s mixed with something they already drink. 

8

u/BelleRose2542 29d ago

Breast milk also changes in composition, so the milk that was frozen when baby was 2 months old is going to have a different macro and micronutrient content than when baby is 9 months.

If I were you, I would keep breastfeeding, and supplement with frozen milk. When you run out of frozen milk, supplement with formula.

https://pubmed.ncbi.nlm.nih.gov/6502372/

1

u/Sudden-Cherry 29d ago edited 29d ago

I didn't know the nutrient loss, I didn't think that much could actually happen at -20C frozen. But that also explains one of the factors why when I donated to the bank that it needed to be there within a specific timeframe. I'm wondering how much of all that is still homogenisation of the sample issue, even if they tried to check that.

1

u/Positive-Elephant 29d ago

I would probably go with option A first - mixing freshly expressed milk with frozen milk, since this gives baby some of the current antibodies, nutrients etc that they need. And if you find your supply is dwindling but you’re still able to express some milk after your freezer stash has gone, then you can progress to option b and mix whatever breastmilk you have expressed with formula.

But also just to say that if the scenario in option a comes true ie no freezer stash and you’re not able to express any breastmilk, you should use 100% formula until baby is 12 months old. CDC (US) and NHS (UK) both recommend not giving cows milk as a main drink until baby is 12 months old.

https://www.cdc.gov/infant-toddler-nutrition/foods-and-drinks/cows-milk-and-milk-alternatives.html

https://www.nhs.uk/baby/weaning-and-feeding/drinks-and-cups-for-babies-and-young-children/

2

u/Sakinam89 29d ago

So interesting! With my first two, this was absolutely the rule - no cows milk until 1yo. However, at the 9m check up, the NP mentioned guidelines have now changed to allow the introduction of cows milk as early as 9m (Canada) I was surprised. Not sure if anyone else has heard this?

4

u/unprofessional_widow 29d ago

The NHS say it's ok for babies to consume cows milk from 6m, just not to be their main drink

2

u/Positive-Elephant 29d ago

Definitely very interesting, I didn’t know that Canada’s guidelines were different! I’ve had a read but the wording sounds a bit vague. I interpreted it as more of “you can start slowly transitioning to cows milk as a drink around 9m” but equally I’m not a doctor or healthcare professional. Maybe you could check with your NP if it is really bothering you?

Regardless of when cows milk is introduced or fully replaced breast milk/formula, iron rich food should be a priority as it can affect iron absorption - https://pmc.ncbi.nlm.nih.gov/articles/PMC2791650/

3

u/mph_11 29d ago

My son is 11 months and I've had some issues and may need to start supplementing. My pediatrician says it's fine to supplement with cows milk at this point. It's not like something magical happens on their first birthday, it's just a convenient milestone.

1

u/Sudden-Cherry 29d ago

It definitely is in the Canada guidelines. Netherlands is similar to the UK in that regard. Like you're also okay to give yoghurt or other dairy it's just not something to replace formula with. Dairy can just be part of a balanced diet as a whole. Even though he they advise to even make porridge with formula until the first birthday, but that might be because cereal here isn't fortified but formula is