Most of my friends’ babies seem comforted by nursing, even when they aren’t hungry. My baby seems just the opposite. Sometimes she is eager to nurse and nurses really well, but other times she acts hungry, starts to nurse and then gets very upset. She arches her back and starts to cry. Have you ever heard of this? This happens several times a day. Is it possible that there is something the matter with my milk? She's always loved to nurse and she has been gaining weight beautifully, so I must be doing something right, but her behavior is very upsetting. She’s only ten weeks old, so I don’t want to stop nursing!
If your baby is growing well and usually seems satisfied with nursing, I’m sure that your breast milk is just FINE! Every mother makes milk that is just right for her own baby at that baby’s age (yes, there are rare exceptions, but in those cases the baby is not thriving and usually has other signs of digestive upsets.) It is possible, but unlikely, that something you are eating occasionally is affecting the taste of your milk, and it wouldn’t hurt to write down what you are eating and drinking (including vitamins and supplements) to see if there is any pattern to your baby’s occasional reaction.
The most likely reason for your baby’s behavior, and one that is typical of babies at this age is that you have a baby who loves to nurse and has learned to associate nursing with both satisfying her hunger and satisfying her need to suck for comfort. My guess is that you have an abundant supply of milk and your baby, who is at an age when she is growing very fast, is often hungry. So, most of the time when she acts as though she wants to nurse, you put her to your breast and she does great. However, sometimes a very young baby who is rooting around for the breast is not hungry—she just wants to suck. Maybe she’s sleepy, maybe she’s just feeling a little unsettled, but she wants that nice feeling she gets when she nurses. So she starts to suck, your milk starts to flow, and all of a sudden she’s very upset, because her tummy is full and she doesn’t want the milk at all. In fact, if she does nurse, she’ll probably just spit the milk back up later (babies are very self regulating in this way!)
All ten week old babies needs to suck to soothe themselves, and some babies need more sucking time than others. For some babies, long and frequent sessions at the breast satisfy this need. Other babies don't like it if they have to eat every time they want to suck, even if the milk is just trickling in. So they do what your baby is doing: they try to suck just for comfort, and then get mad and pull off the breast when they get more than they wanted.
Here’s what you can do to see if this is the right explanation. Next time your baby complains or arches back from the breast, try offering her your little finger to suck on and see if that seems to comfort her. If that works, you can use your pinkie as an alternative to nursing or try giving her a pacifier. At some point, if she really wants to suck without feeding she’ll begin to suck her fingers or her thumb and the problem will be solved.