This is the second volume in an annual series reviewing important areas and advances in obstetric ultrasound, with wide-ranging reviews as well as chapters that look at chosen topics in more depth. This volume again draws together outstanding contributions from radiologists, obstetricians, and scientists to provide full coverage of clinical problems of particular current interest, such as extopic pregnancy, prenatal diagnosis of neural tube defects, fetal cardiac arrhythmias, and non-immune hydrops, while also covering litigations, equipment, and randomized trails of obstetric ultrasound.