Hi, IUDs, Intra Uterine devices are used as a temporary contraceptive agent to avoid conception. There are two types, hormonal and non hormonal. Hormonal IUDs prevent conception by thinning the endometrial lining which usually thickens to accommodate the fertilized egg, make the cervical mucus thick thus inhibiting the sperm motility and prevents ovulation. Non hormonal IUDs contains mainly copper which cause local inflammatory reaction which prevents fertilization of egg by the sperm and also prevents implantation of the fertilized egg, of fertilization occurs. Side effects of the Copper IUDs are heavier bleeding during certain periods after insertion, cramps, spotting or periods in between regular cycles and also irregular periods. Visit the gynecologist to rule out other etiologies of irregular periods. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Pradeepraj, General & Family Physician