9 mo maybe has a digestive issue? He loves all purees and solids but has been refusing enough formula for the last 3 months and is struggling to have regular BM.

My LO was growth restricted and born a little early (36w) and had to be in the NICU at first. So he has always been small. There were times at check ups with the pediatrician where he wasn't growing fast enough and wasn't eating enough. This was true when he was breastfed (until 4 months) and also since then while on formula. Then there were times when he would seem to go through a growth spurt and exceed grown expectations, but we have always had to try very hard to get him to eat enough. Even at 9 mo we keep a log and wake up in the night to feed him since he never eats enough during the day despite great efforts. He will eat any puree and most solid foods as well. He will not drink straight water though, which we have been trying so that he can have a BM easier.

Since he started teething at 6 mo. it seems like he has periods where he becomes even more difficult to feed and also has difficulty having a BM once a day like he did before. I know babies do not necessarily need a BM every day, but when he does not regularly go once a day it is very clear that it disturbs him, causes him to gag more, and eat less.

I was off work today and dedicated the entire day to feeding him - he crawled, did tummy time, did sitting play, practiced assisted standing, rode his rocking horse, had a bath, and had some prunes mixed in with his purees - but no dice. I could not get hime to eat enough or have a BM beyond a very small hard looking piece of poo. It still takes 2 hours at a time to get him to drink about 7 oz of formula. He seems to have a lot of gas, has trouble burping on his own, spits up a lot, and thrashes around violently when I'm trying to feed him (kicking his legs and pushing the bottle away). Once he gets past one day of not having a BM he becomes a baby I don't even know and nothing can make him calm. He just cries and wants to sleep. He already is a good sleeper, so this is not a good thing. When he's like this he would sleep all day.

I've brought these issues up to the pediatrician before (they are more pronounced now, but even since 4mo I felt he was having issues eating and pooping). Our pediatrician kept saying that it would get better feeding him purees and solids. Unfortunately, it's gotten worse even though he loves purees, vegetables, fish, meat, etc. I'm scheduled for a 9 month visit soon and wanted to get some advice before that visit. Thanks in advance for your thoughts.