Miscarriage occurs if there is a failure of embryonic growth or if a viable fetus dies. An incomplete miscarriage is diagnosed by history of bleeding, pain, passage of products of conception and an open internal cervical os on examination. Traditional clinical methods of diagnosing miscarriage have been largely replaced by ultrasound diagnosis. Early pregnancy units have been developed to streamline the diagnosis of abnormal early pregnancy. The Royal College of Radiologists and the Royal College of Obstetricians and Gynaecologists (RCR/RCOG) issued joint guidelines on the ultrasound diagnosis of early pregnancy loss. Low levels of progesterone have long been associated with early pregnancy failure. Treatment regimens include the use of the antiprogesterone, mifepristone and a prostaglandin analogue, the most commonly used of which is misoprostol. These regimens were initially devised for the management of first-trimester therapeutic abortion.