A complete hydatidiform mole is a type of abnormal pregnancy that occurs when an egg with no genetic material is fertilized by a sperm. This results in the growth of abnormal tissue instead of a normal embryo. The tissue appears as a cluster of fluid-filled sacs, resembling grapes, and can lead to complications if not treated. These moles are often detected during early pregnancy through ultrasound, which shows the characteristic appearance. Complete hydatidiform moles can cause symptoms like vaginal bleeding and an enlarged uterus. Treatment typically involves the removal of the abnormal tissue to prevent further health issues, including the risk of gestational trophoblastic disease.