mixing BM with FF?

iVillage Member
Registered: 03-06-2005
mixing BM with FF?
Wed, 04-06-2005 - 11:24pm
I read earlier in one of the other threads something about not mixing BM with formula. Is this true? Ive just started supplementing my DS because I want to provide BM but still be able to freeze some for later. He's @ 5oz 5x a day and I cant always pump 5oz...sometimes 3.5, sometimes 4.5...and its just easiest to mix the formula in with the BM. I read at the LLL site that you should use 2 seperate bottles but I couldnt find ANYthing else on the subject. Anyone know if this is true? And if it is true, why? TIA!
Dana & Cole 12-27-04
iVillage Member
Registered: 03-27-2003
Wed, 04-06-2005 - 11:51pm

I've read that too, but the only reason I'm pumping is because I have to mix Eli's bottles 1/2 and 1/2 w/ formula to "weigh" the breastmilk down, due to reflux. We've been doing this for about 2 wks now w/ no problems. I know it has to do w/ wasting breastmilk if you mix them because if your baby doesn't eat the whole bottle of formula you are suppose to dump them out and so if you mix you'll waste the bottle. I have been reusing the bottles occasionally (usually he pretty much drinks it all at once) and haven't ran into any problem. I always thoroughly smell them though to make sure they are still fine.

Jessie and Eli

iVillage Member
Registered: 01-26-2005
Wed, 04-06-2005 - 11:53pm


The neonatalogists mixed formula with my breastmilk in the NICU to add extra calories. I know this is different from your situation, but if it was dangerous for some reason, they would not have done it. The recommendation not to mix is to limit waste of bm since the two have different shelf lives.


iVillage Member
Registered: 03-28-2005
Thu, 04-07-2005 - 10:40am

I feed bm and ff per ped orders. He was insistent they be in 2 seperate bottles. First bm then 2 oz ff. I didn't think to ask why (dumb me). I did ask twice just to confirm he wanted them seperate. I seem to recall reading somewhere it had to do with iron absorption. Sorry I wasn't much help.


iVillage Member
Registered: 03-25-2005
Thu, 04-14-2005 - 5:40pm

I mix 3/4 BM to 1/4 FF. When it was all BM, I could fill it to the top because BM lasts at room temp for 8-10 hours and he would always finish it. I now make smaller bottles so I dont end up with a gross bottle.

I read that babies have enough iron to last them 3 months and that mothers taking vitamins (I am still on prenatals) will provide the needed iron. HTH

~Vanasa with Walker 2/24/05 (7 weeks today!)


iVillage Member
Registered: 12-22-2003
Fri, 04-15-2005 - 3:25pm

I read some studies when I was thinking about weaning a few months ago that said the intestines of babies are specifically designed to absorb breastmilk (as a live liquid) directly through the sides of the organs. My ped described it as open. Then around 6 months the intestines 'close up.' At that point they are better able to handle other foods. One study talked about the effect of formula on the intestines and that it coats the intestines effectively 'closing' them, decreasing its ability to absorb the breastmilk. I picture a soft gooey red strainer.

It was all difficult to interpret, me not being a doc in the slightest, but I took it to mean bm to 6 months is great. And also any way to allow breastmilk to do its job would be great.

Although I don't know for sure whether or not it matters, we've always used breastmilk if it's there, then formula if no bm is available, on a per feeding basis. For example, I leave the house in th house in the morning with 2 bottles in the fridge of bm. Dh feeds ds until those bottles are gone, then brings out a serving, or whatever he needs, of ff. Rather than planning the day and mixing so that the bm lasts all day. Then I come home with more and we start over.

There's no question that any bm is better than none, so supplementing has still got to be a great thing, I've just always kept the two separate to preserve the integrity of the bm.

Who really knows?

Rebekah (and Quinn, now 8 months)

iVillage Member
Registered: 04-17-2005
Sun, 04-17-2005 - 1:12pm
I have to mix 1 teaspoon of neosure formula with 130ccs of breastmilk because my babies were preemies, so I do not think that mixing them is bad.
iVillage Member
Registered: 04-11-2005
Sun, 04-17-2005 - 1:34pm

I asked the same question when i first joined the board and most ( not all) seemed to agree that it's okay to mix bm & ff. I have been doing it for 4 weeks because my supply is so low and i haven't had any issues since. My DD did have constipated for 5 days but that wasn't because i mixed but because of the iron in the ff. It's very normal for babies to get constipated when they first start on ff.

I agree with most folks that most of the concerns aboout about mixing are about not wasting bm. My DD is usually always happy with 4 oz so when i pre-make the bottle for the nanny i never go pass 4 oz. One time i made a 5 oz bottle thinking she was not getting enough but right when she got to 4 oz, she quit so now i know that 4 oz is the perfect amount for her. To avoid wasting bm, only make what you think your baby will eat. If she doesn't seem satisified afterwards, give her 1-2 oz more. If for whatever reason you do end up with leftovers, i would recommond throwing it away if it's pass 1 hr in room temp. My DD sometimes gets lazy and doesn't eat all 4 oz at once so i let her take a break and then start feeding her again but i never let the bottle stay in room temp more than 1 hr.

So all in all....i think it's safe to mix!!!

Good Luck

iVillage Member
Registered: 02-05-2005
Mon, 04-18-2005 - 11:56pm

Ditto here. I asked this question too and I remember that most of the "cons" where due to wasting BM if the whole bottle was not taken. We give DS a bottle of 1/2 BM and 1/2 FF at bedtime and he has no adverse reactions to it. We've been doing this since 8 weeks and he is now 5.5 months.