On this page:


• To optimise the technology used in the IONA® test in twin pregnancies. This should also reduce the incidence of test failures related to inability to perform the test due to low fetal fraction.
• To explore the performance of the test in different types of twin pregnancies including DZ DC, MZ DC and MZ MC.
• To establish the screening performance of the IONA® test for chromosomal abnormalities in twin pregnancies.

Inclusion criteria

• Currently pregnant with twin fetuses
• Have had or are about to have a conventional screening test
•Intend to continue with the pregnancy at time of recruitment.
• If identified by conventional screening test as ‘high risk’ for chromosomal abnormalities including trisomy 13, 18 and 21,
• Intend to undergo prenatal invasive diagnosis and/or undergoing invasive prenatal therapy.