Conjoined twins. Antenatal ultrasound diagnosis and a review of the literature.

Three sets of conjoined twins recently diagnosed by us in the antenatal period are presented. From these cases and a review of the literature we present the ultrasound diagnostic features of the various forms of this rare condition. We discuss the importance of associated anomalies and shared organs with their relevance to subsequent antenatal management and delivery. The importance of excluding this condition whenever twins are diagnosed on ultrasound is stressed.