What prenatal diagnosis should be offered in multiple pregnancy?

The issues surrounding prenatal diagnosis in multiple pregnancy are complex. Accurate determination of chorionicity is vital and an inability to determine this should trigger consideration for referral to a specialist. The choice of screening method for detection of chromosomal abnormality is limited, and existing data demonstrates the advantages of nuchal translucency screening. The possibility of obtaining discordant results and options for management should be discussed in advance. Invasive tests are technically more difficult and associated with a higher risk of procedure-related pregnancy loss than less invasive methods. Repeat invasive testing is required more often in multiple pregnancies than in singleton pregnancies. Selective termination is technically feasible in both mono- and dichorionic pregnancies, although the risks are higher with the former. It is likely to be more acceptable than high-order multifetal reduction performed in the absence of fetal abnormality.