My son seems to have a problem with gas and spitting up. Could it be something in my breast milk?
Your baby may be sensitive to something you eat or drink, like caffeine or dairy products. If you think what you eat may be affecting your breastfed baby, speak with a Certified Lactation Consultant. But this is not usually the main cause for gas and spitting up. Gas and spitting up are usually caused by the baby sucking in air.
For breastfed babies, their latch may not be quite right. Or they may have mouth issues that affect breastfeeding, like tongue ties or lip ties.
For bottle fed babies, the nipple flow may be too fast, or they may suck in air during or after the feeding. Make sure your baby has a deep latch with their lips turned out. They shouldn't lose suction between gulps, and you shouldn't hear clicking as they feed. When using a bottle, try the pace feeding method, and don't let baby suck in air when the bottle is empty.
Overfeeding is another common cause for gas and spitting up. This can happen with bottle feeding and breastfeeding. If you feel your baby is getting too much milk too fast, look at tips for oversupply here. Smaller more frequent feedings, by bottle or breast, are better for babies with gas or spitting up. Burp baby often and keep them upright for 20 minutes after feedings. Some gas is a healthy sign that your baby's digestion is working properly. Minor spitting up is normal.
It will likely get better once your baby starts to sit up on their own at around six months old.
SOURCE: https://www.askdrsears.com/topics/health-concerns/fussy-baby/comforting-gassy-baby