The criteria for diagnosing embryo arrest generally involve the appearance of the embryonic bud and heart tube between six to eight weeks. If these are not visible beyond eight weeks, the situation is referred to as embryonic arrest. Embryonic arrest requires abortion, which for safety reasons typically involves hospitalization and a combination of medication and uterine evacuation. However, if the gestational sac is relatively small, an outpatient abortion procedure might be sufficient. Whether hospitalization is necessary should be assessed by a doctor, who will consider factors such as previous scar pregnancies, the condition of a scarred uterus, and the size of the current gestational sac, to make a comprehensive decision.