Breastfeeding is a huge commitment, which requires a lot of patience, and while it can help create and strengthen the bond between mom and baby, it can also cause some frustration once in a while. If your baby seems to cry and fuss when you nurse, it can be confusing and difficult for you to deal with. You may be doing more than just wondering, "why is my baby fussing while breastfeeding?" You may be ready to give it all up.
About one month into breastfeeding my daughter, she became incredibly fussy as I nursed her. She would feed for a few minutes, and then begin to pull off and start crying; she was hungry, but it seemed like she was struggling. After taking her to the pediatrician, I found out that she was suffering from reflux, and a week or two of Zantac helped cure her fussiness.
According to Breastfeeding Problems, aside from reflux, babies can be fussy while breastfeeding due to a let-down which is either too fast or too slow. If your let-down is too fast, milk can be forced out with a bit of pressure, causing the baby to gulp, gasp, or choke, which will definitely make the baby uncomfortable. If your let-down is too slow, your baby may feel like they aren't getting enough milk fast enough and become increasingly frustrated at suckling with no results.
Kelly Mom explained that a baby can be fussy at the breast due to excessive air they might take in while breastfeeding as well, in which case they might require you to burp them more often — before, during, and after each nursing session. Kelly Mom also noted that teething pain, thrush, or even tongue ties can make your baby fussy while breastfeeding.
If your baby is fussing while breastfeeding, it's important to call your pediatrician to make sure there is no underlying pain or condition causing it. You should also enlist the support of a lactation consultant, who can help you diagnose and properly treat any breastfeeding issue you might have, so that you and baby can go back to a happier breastfeeding experience.