Q. My baby is taking significantly less milk than before. Should I change the formula?

Hello doctor,

My son is 14 weeks old. His weight is 7 kg and length is 65 cm. He is formula fed since birth. I noticed that in the last month he began to take significantly less milk than before and I cannot understand why. Between 1 to 2 months of age, he used t drink around 1000 mL per day. However, between 2 to 3 months of age, he went from 1000 mL to around 850 mL. He seems agitated when he drinks, flails legs and arms; sometimes he will not suck well and just bite. Then, he will drink around 90 to 130 mL and rejects the bottle, but he will continue to suck on his hands and moan. He will grimace at the bottle and even vomit if I insist on giving the bottle.

His bowel movements are regular to around once or twice a day, yellow and soft. Sometimes, he has a bit of reflux after eating (some milk coming out), but less than before. How to fix this problem? Am I doing anything wrong? Should I change the formula?

He has gained 1 kg in the last one month, but I am concerned that he seems to drink less milk as the daily quantity keeps going down. He drinks around six times per day around 140 mL each time.