# How much does breastmilk change over the course of nursing? **URL:** \ **Category:** Factual Questions\ **Created:** [December 1, 2008, 6:18pm UTC](https://boards.straightdope.com/t/how-much-does-breastmilk-change-over-the-course-of-nursing/475214 "2008-12-01T18:18:41Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [December 1, 2008, 6:18pm UTC](https://boards.straightdope.com/t/how-much-does-breastmilk-change-over-the-course-of-nursing/475214/1 "2008-12-01T18:18:41Z")
My wife is away at a conference which leaves me defrosting milk we’ve stored up. I’ve been using the old stuff from August. My wife says that breastmilk changes over time for the neads of the child. She says I should mix the new stuff with the old stuff. Does it make a significant difference? ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [December 1, 2008, 11:22pm UTC](https://boards.straightdope.com/t/how-much-does-breastmilk-change-over-the-course-of-nursing/475214/2 "2008-12-01T23:22:58Z")
Allright, I’m going to bump this once. I thought there would be more people that knew stuff about breastfeading here. ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [December 1, 2008, 11:52pm UTC](https://boards.straightdope.com/t/how-much-does-breastmilk-change-over-the-course-of-nursing/475214/3 "2008-12-01T23:52:16Z")
Hello, yes, sorry…experimenting with this thing called “having a life”. I’m finding it overrated. You? Ah, yes, breastmilk. Your wife is right, it does change over time, both in the course of a feeding (being mostly water near the end) and over time as the infant grows and his needs change, the levels of fat, protein and carbs all change. If all you’re feeding the child is expressed milk, it’s not a terrible idea to mix up some new with some old, but it’s not necessary, nor is it explicitly recommended anywhere that I can find. If the child is healthy and is getting some milk at the breast and some from the freezer, or if this is a short term temporary thing, then it shouldn’t matter at all. Really, on the list of things to worry about as a new parent, this is way down there. The fact that the baby is getting breastmilk at all puts him way ahead of the curve. But if he seems hungrier than normal, combine or switch to the current stuff and see if it satisfies him better - he could be in a high fat phase. ---
**Author:** ![JaneSaintClair](https://avatars.discourse-cdn.com/v4/letter/j/9fc29f/32.png) [@JaneSaintClair](https://boards.straightdope.com/u/JaneSaintClair)\ **Post date:** [December 2, 2008, 12:00am UTC](https://boards.straightdope.com/t/how-much-does-breastmilk-change-over-the-course-of-nursing/475214/4 "2008-12-02T00:00:36Z")
Breastmilk does change over time, with the most noticeable changes during the first few days and weeks. So, a lot depends on how old your infant was when she pumped. Here are a couple of links: [http://extension.oregonstate.edu/fcd/nutrition/publications/nutrifocus/breastmilkchanges.pdf](http://extension.oregonstate.edu/fcd/nutrition/publications/nutrifocus/breastmilkchanges.pdf) > **[Milk Production FAQ](https://www.bfar.org/milkfaq.shtml)** > > The BFAR website provides information and support to mothers who wish to breastfeed after breast or nipple surgery, and their friends and family. It is also an online resource for healthcare providers who help mothers breastfeed. But, your best resource is most likely the La Leche League… that’s where most of the breastfeeding experts hang out. You might want to try posting your question to their forums. Here is the site: [http://www.llli.org/](http://www.llli.org/) ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [December 2, 2008, 12:13am UTC](https://boards.straightdope.com/t/how-much-does-breastmilk-change-over-the-course-of-nursing/475214/5 "2008-12-02T00:13:23Z")
> [@WhyNot](#): > > Hello, yes, sorry…experimenting with this thing called “having a life”. I’m finding it overrated. You? As a new dad, I’m going to have to ask you what you mean by “having a life.” Is it something like slaving over every whim of a 5 month old while trying to keep the house in decent order? I think I remember some time ago that there was this thing I called “having a life.”, but it’s all a distant memory. ---
**Author:** ![Snnipe\_70E](https://avatars.discourse-cdn.com/v4/letter/s/b5a626/32.png) [@Snnipe\_70E](https://boards.straightdope.com/u/Snnipe_70E)\ **Post date:** [December 3, 2008, 3:45am UTC](https://boards.straightdope.com/t/how-much-does-breastmilk-change-over-the-course-of-nursing/475214/6 "2008-12-03T03:45:26Z")
I am going to pick this thread to bring up something important. Consider checking your area to see if there is a Mother’s Milk Bank. Ask your wife if she would be willing to donate? Lives are saved by the few Milk Banks accross the world. ---
**Author:** ![Solfy](https://avatars.discourse-cdn.com/v4/letter/s/848f3c/32.png) [@Solfy](https://boards.straightdope.com/u/Solfy)\ **Post date:** [December 3, 2008, 4:46am UTC](https://boards.straightdope.com/t/how-much-does-breastmilk-change-over-the-course-of-nursing/475214/7 "2008-12-03T04:46:39Z")
There was a good article about breastmilk in [C&EN](http://pubs.acs.org/cen/coverstory/86/8639cover.html) news that mentioned that milk composition over a three month period may not vary as much as previously thought: “And although some researchers have reported that the number of oligosaccharides varies over time as the infant grows, recent work by Lebrilla and coworkers shows that that is true only for minor oligosaccharide components of human milk—the quantity of the major components stays relatively constant over a three-month period (J. Agric. Food Chem. 2008, 56, 618).” (although your time period is a little larger) ---
**Author:** ![Cliffy](https://avatars.discourse-cdn.com/v4/letter/c/59ef9b/32.png) [@Cliffy](https://boards.straightdope.com/u/Cliffy)\ **Post date:** [December 3, 2008, 2:31pm UTC](https://boards.straightdope.com/t/how-much-does-breastmilk-change-over-the-course-of-nursing/475214/8 "2008-12-03T14:31:10Z")
We were told to throw it out after three months, but within that period it was fine. During a couple growth spurts Zoe had a few days where she was drinking 2/3ds or more of her daily consumption from the freezer, and most of it at least a couple months old, and she suffered no ill effects. (Although she was probably 10 or 11 months by that point, so a little older.) If I were you, I don’t think there’s that much hassle with mixing new and old. But depending on how much is in one batch of frozen, it might mean you have to thaw and mix more than the kid’s going to drink, which means you have to pitch a lot of milk, including fresh stuff. If that’s the case, I think you’re better off not mixing so you can avoid the waste. –Cliffy ---
**Author:** ![Ca3799](https://avatars.discourse-cdn.com/v4/letter/c/9f8e36/32.png) [@Ca3799](https://boards.straightdope.com/u/Ca3799)\ **Post date:** [December 3, 2008, 3:25pm UTC](https://boards.straightdope.com/t/how-much-does-breastmilk-change-over-the-course-of-nursing/475214/9 "2008-12-03T15:25:38Z")
(WhyNot-Hind milk is the fatty milk.) There is not enough difference between the fresh and frozen milk to make any difference to a healthy baby. Milk does change slightly over time (colostrum, for example) but not enough to matter unless the baby has special health needs. Even with special health needs, you would likely be doing everything the same, fresh and frozen wise, but also adding human milk fortifier or extra vitamins or medications or something to the milk. Your wife probably has a schedule and plan to using both the fresh and frozen that keeps the frozen being used in an orderly fashion. I recall doing the same (mixing fresh and frozen. adding HMF and meds, etc.) and being kinda picky about it at the time. The kid is 11 now and I can tell you from hindsight that it doesn’t really matter in the larger sense, although it seemed to be a ‘big deal’ at the time. ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [December 3, 2008, 3:34pm UTC](https://boards.straightdope.com/t/how-much-does-breastmilk-change-over-the-course-of-nursing/475214/10 "2008-12-03T15:34:32Z")
> [@WarmNPrickly](#): > > As a new dad, I’m going to have to ask you what you mean by “having a life.” Is it something like slaving over every whim of a 5 month old while trying to keep the house in decent order? I think I remember some time ago that there was this thing I called “having a life.”, but it’s all a distant memory. Yes, it’s this weird thing where one’s spouse is away with the small child for 6 days and the elder child is at grandma’s house, and one finds oneself utterly alone…for about 15 minutes. Then the “friends” I vaguely remember started coming over and dragging me places involving music and alcohol and food, and it’s all a bit blurry after that. In short, I conclude that both “having a life” and “not having a life” are blurry and exhausting, but in entirely different ways. ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [December 3, 2008, 5:21pm UTC](https://boards.straightdope.com/t/how-much-does-breastmilk-change-over-the-course-of-nursing/475214/11 "2008-12-03T17:21:08Z")
> [@Solfy](#): > > There was a good article about breastmilk in [C&EN](http://pubs.acs.org/cen/coverstory/86/8639cover.html) news that mentioned that milk composition over a three month period may not vary as much as previously thought: > “And although some researchers have reported that the number of oligosaccharides varies over time as the infant grows, recent work by Lebrilla and coworkers shows that that is true only for minor oligosaccharide components of human milk—the quantity of the major components stays relatively constant over a three-month period (J. Agric. Food Chem. 2008, 56, 618).” > (although your time period is a little larger) You’d think I would have seen that article, but my subscription was on hiatus at the time. My wife was bringing hers home, but I haven’t been much into reading it lately. It’s good to know that I can just use the old stuff up. That way we have a usable supply for longer. > [@Cliffy](#): > > We were told to throw it out after three months, but within that period it was fine… We were told six months in the deep freeze was good, but given how anal people are about this stuff, I’d have no qualms about a using it a year later. > [@WhyNot](#): > > Yes, it’s this weird thing where one’s spouse is away with the small child for 6 days and the elder child is at grandma’s house, and one finds oneself utterly alone…for about 15 minutes. Then the “friends” I vaguely remember started coming over and dragging me places involving music and alcohol and food, and it’s all a bit blurry after that. > > In short, I conclude that both “having a life” and “not having a life” are blurry and exhausting, but in entirely different ways. Actually, at this point, my little girl is still pretty simple to please and take care of. It’s really a year from now and the following seventeen years that worry me. ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [December 3, 2008, 8:11pm UTC](https://boards.straightdope.com/t/how-much-does-breastmilk-change-over-the-course-of-nursing/475214/12 "2008-12-03T20:11:17Z")
> [@Ca3799](#): > > (WhyNot-Hind milk is the fatty milk.) :smack: Of course, you’re right. I actually had to go up and read what I wrote 'cause I knew that. Brain fart while typing. I think it’s kinda cool, really: if the baby is so hungry that he nurses longer, he gets the more filling stuff and also triggers production of greater quantities. If he’s just a little peckish, he stays well hydrated by getting a lot of water. Neat, isn’t it? And, unfortunately, a benefit lost to the convenience of pumping and bottle feeding. (My preemie’s milk, by the way, was \*all \*hindmilk. It looked homogenized, even after sitting in the fridge for a while. Thick and white as a milkshake, none of that thin yellow stuff underneath. Preemie milk really is a whole different thing.)