Is this silent reflux?

LO refuses breast second time around but takes bottle

Ever since 11/12 weeks of age, my LO would feed from one side for 8-12 mins and then get really fussy if I tried to pop her back on even after a burp.

At first I thought this was her being done and would not force her back on even though I could feel I was still somewhat full and not completely drained out.

Then, when her 2 month vaccine appointment showed very little weight gain, I decided to supplement with expressed milk in bottles to see if she would take it.

Surprise, surprise not only would she take the 1.5-2 oz top up, she’d gobble it down.

My LO is 14 weeks now. At any given time of the day, her feeding pattern is 8-12 mins (sometimes 15 in the middle of the night) on one side. When she pops off on her own, I burp her a few times and try to get her back on the same breast or the other breast.

95% of the time she refuses it by arching back, turning her head away or if she gets back on making a slight gagging sound.

When this happens I don’t force her back on but give her the bottle of 2 oz after a few minutes. It’s worth noting that it is not a bottle preference as she was refusing round 2 even before I introduced bottles.

A weighted feed showed she transfers around 22-25ml in a 10 min session so I know she’s not getting enough. Very rarely do I get her back on or she does a longer session in the first go that I feel drained.

Sometimes she’d get back on the breast after a 10-15 min break.

Does anyone have any insight on why this is happening?

For reference, LO does not have any oral ties but does have slow weight gain. She is generally a very happy albeit small baby who’s meeting all her milestones. Little spitups are common but there has been no major issues.

The refusal to get back on the Breast by arching back or limiting her intake makes me think - is it an allergy or silent reflux?