Prenatal diagnosis has undergone an explosion of growth in the past two decades. The primary impetus for this rapid expansion has come from the widespread use of prenatal ultrasonography. Most correctable malformations that can be diagnosed in utero are best managed by appropriate medical and surgical therapy after maternal transport and planned delivery at term. Prenatal diagnosis may influence the timing (Table 5.1) or the mode (Table 5.2) of delivery, and in some cases, may lead to elective termination of the pregnancy. In rare cases, various forms of in utero therapy may be possible (Table 5.3).