maybe try to change the formula? 12 days is too long for babies not to poo. my baby is also 2m+ and the longest she didnt poo is only max 2days. after every shower, try to massage his tummy gently with minyak telon/yu yee oil and do alot of bicycle motion(not only helps for gassy tummy in my opinion). every play time, help him to sit and stand for a bit. it helps with peristalsis movement,same like adults.
My lo 5 days did not poo and could not finish his usual amount of milk during those 5 days.. he only drink about half of his usual amount. Every time he see milk bottle he will cry his lung out. But once he poonami, he can drink more, abt 75pct of usual, going toward his usual amount.
Hi just a advice will it be the fm that's making your baby constipation? Some bf baby don't poo but majority normally will have poonami.
If it’s me I will monitor baby’s behaviour. If I sense something is not right I’ll bring to doctor