I have switched my son from enfamil lipil with iron to prosobee. He has alot of problems with gas, not being able to poop, and spitting up (ALOT) He is gaining weight beautifully, so the doctor said he might just be eating too much. So we switched to the prosobee and it has been 3 days and he seems to spit up more, but he is now pooping on his own (without the help of prune juice the dr suggested) a couple of times a day. He is still passing a ton of gas. How long will it take for me to figure out if the prosobee is better for him? I think the added iron in the enfamil lipil was causing constipation, but I am not for sure. If any of this makes sense or someone can help, i'd really appreciate it.