ABSTRACT
An important premise to this chapter is that, since this text is malformation-oriented, we have concentrated on congenital anomalies, leaving out most of the important issues related to genetics of twinning and risk of preterm delivery. Hence, in this chapter, we will deal with the following questions: 1) when is the risk of finding a congenital anomaly increased in twins? 2) what type(s) of anomalies are more likely to be present? 3) is there any anomaly specifically related to developmental pathology of twinning and what is its treatment?
