If she is not actually eating the fibers from the blankets, or chewing holes, I would not worry. A few swallows of some short blanket fuzz now and then wouldn't be different from the cat swallowing her own fur while grooming. Maybe you can get different warm blankets that are not fuzzy. If the blankets are wool, they could be very attactive to cats to suck on since the lanolin in wool smells a bit like the mother cat's wet fur nipple area.
I would not want to use any adversive technique on a cat who is doing something to find comfort. I would worry it would stress her and cause her to do it more to get more comfort. Or start some stress related behavior such as overgrooming. It it bothers you, try distracting the cat with something pleasurable, such as a fishing pole type toy waving around, or move her slightly from what she is sucking on while giving a the major kitty massage petting session to give her a different way of receiving comfort. I would go more for the last option since it is closer to the mama/baby nurturing feel that the sucking cat is seeming to want to be feeling.
Maybe some things to help reduce stress in general would decrease the sucking behavior (more scratching posts, interactive play sessions daily, special petting sessions daily, high places available for the cat to go on, etc.) If you have more than one cat, adding additional cat things helps (another litter box, a new, separate feeding area, additional places for the cats to go (cat tree, additional window perch, another pet bed, etc.)
Some people think another reason some cats suckle on fabric is to try to get more fiber. I don't know if that is true, at least not in the case of a cat taken too soon from it's mother, but growing some cat grass for you cat will add some fiber and most cats love it. Some cats vomit after eating grass, which is good since it helps clean out their stomachs from any hair (or fibers) they have swallowed to avoid hairballs from forming.
I really don't see any need to stop a cat from occasional sucking on fabrics as part of a cat's happy comfort time. I would keep up with routine vet exams to be sure there is no health problem.