I am an RN who monitors newborn weight/growth. I have had two infants in the past 8 months, one 2 months old, other 5 months old that were having slow weight gain, sometimes weight loss. Determined cause was the baby brezza. Was using incorrect settings. It is far to easy for parents to use the incorrect setting if they do not read instructions fully. Fortunately, these two infants did not develop electrolyte imbalance which could happen.