Is there really a correlation? I had to use one for a couple of months w/ DD1 and as I think back, it was the only time I ever battled plugged ducts. I'm using one with DD2 (8 weeks old) Over the weekend, I had a pretty nasty plugged duct, complete with fever for about 48 hours. I read on the kellymom site that they are one of the possible causes, but that's the first time I'd heard of that. Has that been anyone else's experience? I'm trying to wean off the nipple shield, but it's going to take a little time, especially at night.