Can such random withdrawal bleeding be a side effect of birth control pills?

Hi, for almost a year i have been taking axia birth control pills (oststnio changed to axia conti). The problem is that the bleeding I have more irregular, after 4 packs there was several days of middle-cycle bleeding, during the break did not occur. It can be said that about 5 packs of bleeding occur once a month, or for 2 months. Currently, it will not work, since the last intercourse I have performed a home and blood test after 7 week, both negative, and the tablets are taken because of a detected cyst on the ovary. Can such random bleeding simply be a side effect?