Management of discordant fetal anomaly

Twin pregnancies may be complicated in a number of ways, including through presentation with fetal abnormality. Pregnancies that are discordant for fetal anomaly may be impacted by a range of complications which are dependent on zygosity, chorionicity and the specific anomaly concerned. Discordance is defined as "occurrence of a trait or disease in only one member of a matched pair of subjects, especially twins". In this chapter, we have reviewed the prevalence of various fetal anomalies in twin pregnancies, identified means for detecting these prenatally and reviewed a range of approaches to managing these anomalies considering the impact on the affected fetus, the co-twin and the wider family.