Taking an abortive pill sometimes can sometimes lead to irregular menstrual cycle after a period of one month or so. The next two cycles after an abortion pill can be irregular because of many reasons. It could be because of the hormonal pill itself. The mefipristone component of the abortion pill also may be a contributing factor for the irregularity of the menstrual cycle. Sometimes it could be treating bits of conception which might be present and this has to be ruled out by doing an ultrasound. Sometimes it could be because of persistent corpus luteal cysts in the ovary. If a persistent corpus luteal cyst is noted either treat it by a combined contraceptive pill or wait for one or two months, then for the cycles to regularise. Usually the abortion pill induced irregularity in the menstrual cycle recover and become normalized after a period of 1 or 2 months without any treatment. But sometimes this irregularity persists for a longer time. It has to be treated.