Hello, my wonderful son and firstborn is now 6 weeks old! I am a first time mom, trying to learn about pumping/how to care for a newborn in general lol.
I latched him from the hospital, feeding on demand; not to exceed 2 hours, up until his 2 week wellness check. He wasn't gaining weight and dr recommended we do formula until he regains his birth weight. I still wanted him to get the breastmilk benefits, so I started pumping, while also giving formula. We would alternate formula and breastmilk bottles. I quickly learned my supply was struggling, I was barely keeping up with his 2 oz every 2 hours (with the formula bottles in between) He's now up to 4 oz every 3-4 hours and I struggle to keep up with that as well (again alternating, 2 formulas bottles to 1 breastmilk bottle) My point in sharing this is that by no means do I make enough for an oversupply, I struggle to keep up with giving him the breastmilk bottles he does get.
The past 2 days I have noticed that he has been extremely fussy when starting a breastmilk bottle. He will cry and cry for the first few min, like really cry, I'll soothe him and we eventually get to a place where he will drink it, but this hasn't happened before. It's not every breastmilk bottle, its been random ones the past 2 days, but he isn't doing this with the formula bottles.
The only thing I have changed (I have since stopped just to rule it out) is combining the freshly pumped milk with already chilled milk. I also started doing this over a week ago and again this has been the past 2 days. I was originally chilling before adding, but I kept reading differing guidance that you didn't need to do that. I understand the concern of milk being combined and that there is old milk, but again I am barely keeping up with him, so if anything the "oldest" milk he would be drinking wouldn't be over 24 hours in the fridge. I also have not changed my diet or anything recently. I do use the fridge method for pump parts, but wash/sterlize at the end of the day before bed.
Could this be the cause? Is there anything else I am missing that may be causing this? Can he develop an aversion to the milk? This has made me super sad that my milk is possibly upsetting him. I will add thatmhis diapers have not changed, they have been normal.
Thanks for any advice!