My 4 month old baby is on formula and he has this habit of spilling a little milk every time he burps.Though I take care that he is not laid down after having milk and make sure he is in an upright position for a while after each feed. But still he spills a little milk every time he burps. Should I be worried about it or is it normal for babies. I am worried if the cause for this could be some stomach infection. I would be glad to receive your valuable advice on this.