Non-Invasive Chromosomal Evaluation of Trisomy Study

Inclusion Criteria: * 1\. Subject is at least 18 years old and can provide informed consent; * 2\. Subject has a viable singleton or twin pregnancy; * 3\. Subject is confirmed to be at least 10 weeks, 0 days gestation at the time of the study blood draw; * 4\. Subject is planning to undergo CVS and/or amniocentesis for the purpose of genetic analysis of the fetus OR the subject has already undergone CVS and/or amniocentesis and is known to have a fetus with a chromosomal abnormality confirmed by genetic analysis. Exclusion Criteria: * 1\. Subject has known aneuploidy; * 2\. Subject is pregnant with more than two fetuses or has had sonographic evidence of three or more gestational sacs at any time during pregnancy; * 3\. Subject has a fetal demise (including natural or elective reduction) identified prior to consent; * 4\. Subject has history of malignancy treated with chemotherapy and/or major surgery, or bone marrow transplant;