My son is 4 weeks old today. I give him breast milk in a bottle fortified with neosure. The last few days he's been spitting up nearly half his meals. I make sure to burp him 3-4 times during each feeding and not to force him to drink more than he wants. He goes to the doctors tomorrow so I will ask them about it then but wanted to get some advice from other moms as to why this may be happening. Thanks in advance!