My daughter was not diagnosed until she was 9 months, but she was on pregestimil for the first 2 months anyway, because she had some digestive problems (may have been CF related, but we do not know) between 2 and 9 months she was just on regular formula. Once she was diagnosed at 9 months,, she was on regular formula she had to have enzymes with every feeding. Some babies are pancreatic sufficient at birth. Rachel gained well and progressed along the growth curve nicely until she was 6 months old, then she was probably losing pancreatic sufficiency. They might let you try regular feeds without enzymes and then do a fecal fat test to determine if the baby is pancreatic sufficient or not.........Good luck and CONGRATS!!!!!!!Andreamom of Rachel 5 with CF and a boy on the way