i took the BF pill for over a year and had no problems with it. according to my obgyn, as long as you are still nursing 2-3 times a day it should be as effective as a "regular" pill. but if you get down to less than that, you should go to a normal BC pill. i exclusively BFed my baby until she was 6 months old, and then continued BFing about 8-10 times a day until she was 10 months, then we weaned down to 3-4 times a day for a few months and finally weaned off around her 14 month mark. my period didn't even return until the first weaning, around her 11 month mark.
hope this helps. if you have any questions about ANYTHING, (especially anything BF related) feel free to message me. i love to help! :)