A hydatidiform mole -is a growing mass of tissue inside your uterus (womb) that will not develop into a baby. It is the result of abnormal conception. It may cause bleeding in early pregnancy and is usually suspected on an early pregnancy ultrasound scan. It needs to be removed and most women can expect a full recovery. However, close follow-up is needed after a hydatidiform mole because there is a small chance of developing a type of cancer.