This chapter describes unexplained fetal death. In most patients, the only symptom is decreased fetal movement. Although on auscultation inability to obtain fetal heart tones is suspicious, ideally death must be confirmed by real-time ultrasound. Once diagnosed, management needs to be directed both towards ascertaining the cause of death, and terminating the pregnancy with minimal risk to the mother. Attempting to determine the cause of fetal death remains important because it may influence estimates of recurrence, future preconception counseling, pregnancy management, prenatal diagnostic procedures and neonatal management. Another important purpose of investigation is to assess present maternal wellbeing and ensure prompt management of any potentially life threatening maternal disease.