Any previous pregnancy with reported full trisomy of chromosomes 13, 18 or 21, meeting the following criteria:
Inclusion:
•From 10 weeks (gestational age confirmed by dating scan) and up to 21 weeks and 6 days (21+6) of pregnancy.
•Two attempts at NIPT per pregnancy can be offered.
Exclusion:
• Maternal cancer (unless in remission)
• Blood transfusion in the last 4 months (whole blood or plasma)
•Bone marrow or organ transplant recipient
•Vanished twin pregnancy (an empty second pregnancy sac or a second pregnancy sac containing non-viable fetus)
•Maternal T21
•Maternal balanced translocation or mosaicism of T21, T18 or T13
•Immunotherapy in the current pregnancy, excluding IVIg treatment
•Stem cell therapy
•Previous pregnancy was not a full trisomy (reciprocal translocation or partial trisomy)
•The current pregnancy was conceived using a donor egg (unless the egg for this pregnancy is from the same egg donor used in a previous pregnancy diagnosed with Down’s, Edward’s or Patau’s syndrome)

For any enqueries relating to referring samples contact: thesafetest@stgeorges.nhs.uk