Have you had any irregular menstrual cycles ?
Any white discharge or itching in vagina ?
Usually one of the commonest complications of IUD is bleeding. In some cases, hormonal
disturbances or infections can cause bleeding not in your cycle. It would be wise to consult your Doctor to get you examined for any infections or menstrual disorders. You period shall become regular in a few weeks. If not you may get a trial for OC pills to regularize your cycles. Keep proper hygiene. Practice safe sex