Q&A: could pumping be changing the composition of breastmilk?

Joyce writes:

"My 5 month old son has always been a prolific spitter-upper.  I amtalking volumes.  We have always marveled that he is able to grow with the amount of spitting up that he does (17 lbs, 4 oz at 4.5 months!). He not only spits up right after a feeding, but even up to two hours afterward.  He is always in a bib, and we usually go through at least 6 bibs and four changes of clothes a day -- and we're not being overly fastidious and trying to keep him in "clean" clothes necessarily; we change him when the spit-up stink gets to be overwhelming.  I made some long-term, serious dietary changes to see if that would help (from months 2 - 4, no dairy, no legumes, no cruciferous vegetables, etc.). No dice. His pediatrician put him on Zantac to try to control the spitting up, and we thought it was helping.

I am a full-time graduate student.  Over winter break, I noticed that his spitting up declined substantially.  We even made it through several days with only one bib and no outfit changes!  I thought maybe he was growing out of the spitting up.  Either that, or it was the Zantac, since he  started it just before my winter break began.   

My classes resume tomorrow, and his spitting up has also returned.  Today we've gone through five bibs and five outfits.  I haven't changed his number of feedings, nor have I changed my diet.  The only thing different: I didn't pump during winter break, and I have gone back to pumping to build up a stash of breastmilk for his return to daycare while I am in class.  I am now assuming that the pumping is causing his spitting up. 

Have you ever heard of such a thing?  If so, what can I do?  I don't want to feed him formula while he's in day care yet, so I'd need to keep pumping.  Should we all just live with the spitting up as long as I am pumping?"

That's a gross problem. But remember that spitting up, as long as the baby isn't in pain, isn't an actual health problem. For years I've been hearing and repeating the quote that "spit-up isn't a medical problem, it's a laundry problem," and then Jamie (author of the great "Why Is It So Hard To Breastfeed A Baby?" and "What's the normal learning curve?" posts) told me the original source was  Dr. Greg White (husband of La Leche League co-founder Mary White).

My first thought was that the pumping was changing something about the amount of milk Joyce produces, or the ratio of foremilk (watery with a lot of lactic acid) to hindmilk (fatty and creamy and sticks to the ribs better). So I decided to get a second opinion from Jamie. Here's what she said:

"It could be foremilk/hindmilk imbalance with a more abundant milk supply, or it could be that her letdown is too forceful for him when she has more milk.  Gulping to keep up with the flow of milk can mean a lot of spitting up later.  A couple of ideas off the top of my head: nursing against gravity helps with overactive letdown.  She could lean back in a recliner, or in the corner of the couch, or try nursing while lying down when she's at home.  Sometimes positioning the baby so he's straddling the mother allows her to lean back more comfortably and puts his mouth higher in relation to her breast.

Alternatively, she could try pumping off some of the milk right before he nurses.  If she pumps or hand-expresses first thing in the morning (or whenever her breasts feel especially full) so she can offer the baby an empty-ish breast, it's likely to be less of a problem.  If a pumping session is too much to stomach first thing in the morning, she could try nursing with a towel handy.  When she feels the letdown begin, she could unlatch the baby for a minute, let that milk just flow into the towel, and then reconnect the baby again afterward.  It's that first letdown that will probably be the most forceful."

Those suggestions should help when Joyce is at home nursing. For the pumped bottles, it may just be the foremilk/hindmilk imbalance and there isn't anything to be done about it. (I'm assuming she's already checked to make sure there isn't that sour or soapy taste characteristic of pumped milk in women with excess lipase issues.)

Joyce, I think you're just going to have to decide which would be worse to you, to switch to formula at daycare or to keep doing so much laundry. If you start him on solids at around 6 months, that might also help him keep things down a little more. My guess is that as he gets older and that muscle at the top of his esophagus gets stronger, combined with eating more solid-ish foods, the spit-up problem will fade away.