Death of the fetus after 20 weeks of gestation complicates about 1% of pregnancies. Of various means of diagnosing fetal life and death, real-time ultrasound visualization of the fetal heart is the most accurate. Delivery of the dead fetus can be effected by various means, but in most instances, at least before 28 weeks and perhaps thereafter as well, the simplest and most effective method is with prostaglandin vaginal tablets. A variety of conditions are known to cause fetal death or increase the risk that it will happen, but these account for only about 50% of cases. Four special tests may identify a cause of the "unexplained stillbirth" in the other 50% of cases. These tests include karyotype, listerial culture, fetomaternal hemorrhage, and lupus anticoagulant.