4 month old sick - formula or sterilisation?

[MrsEK1991]

Hi - my son is 20 weeks and has been exclusively breastfed since birth. Last weekend we tried him on ready made Cow and Gate formula for one feed a day to see if it would help him nap better. He had it on Friday, Saturday, and Tuesday. On Thursday he refused the formula, and on Friday he only had 2oz before refusing. About 3 hours later he was really sick (no temp but vomiting). Since then hes been absolutely fine but it was a horrible evening seeing him poorly and has scared us a little. My husband thinks it was the formula, but I’m worried it might have been a badly sterilised bottle as I’m not used to that bit. Do either of these sound likely? Or could it just be something unrelated? I don’t want it to put us off formula completely because he seemed to really like it, but we don’t want to risk making him ill again. Any ideas would be great thanks all!

Sometimes they don’t get on with a particular brand of formula. Maybe try another one.

It could just be a bug. Has be been BF as normal? If he's used to breastmilk, it could just be physically too much milk for him in one go.

With it being ready made formula, was it in an individual carton or large bottle? The large bottles should only really be stored in fridge for 48 hours maximum once opened.

I'd try again but with a different brand of formula.

BF babies take on average 1 floz per hour. So if he usually feed every 3 hours, his tummy probably can't cope with more than 3 floz.

Formula fed babies have to take in increasing amounts to get the nutrients they need so are used to drinking much bigger volumes.

It could just be that he's drunk too much or he doesn't suit that brand.

Just one more point though, solids and formula do not help with sleep

One tip is to not leave bottles around after they finish them, granted this is older ages when they can hold them themselves.

Our one drank last nights milk the next morning more than once, never any issues.