It’s true that pump volumes aren’t a good judge of oversupply but I’d be really reluctant to say its oversupply if she’s working with an LC.
The thrush can cause continued pain with pumping (especially burning) even on a low setting. Bacterial infection can cause the same symptoms. Often if a mom is not responding to what seems like thrush it may also be bacterial and need antibiotics in addition to yeast treatments. Some moms need to hit the yeast hard, heavy and long to see improvement. It can be very tricky to figure out what exactly is going on yeast vs bacteria or both and she should be working closely with the LC and her OB doctor. (they should also be talking to each other …the LC and doc)
The plugs and mastitis can be from continued inflammation b/c of unresolved infection (yeast or bacterial). Yes, it can also be from oversupply…………sigh……..as my family doc loves to say……everyone is entitled to more than one problem….It could actually be a combination of infection and oversupply, and a poor latch and related to the shield. However, the shield may be helping. Again, this definitely sounds like a job for an in person LC and doctor.
Certainly it would be important to check the flange sizes too but I bet that’s not the entire picture. Ameda has a very nice picture of how they should fit on their site.
When moms have complex problems such as this it’s important for them to be persistent with their health care providers and LC’s and make sure they are aware that she is not responding or not responding completely to the treatments. She can also ask for another opinion of either the LC or the doctor or both if she feels they are not able to help. A good LC and good doctor will refer to someone else if they are not able to help anyway.