The overall significance of this study is to develop a laboratory developed test (LDT) to use a new marker in the maternal blood to better identify pregnancies that have a child with a chromosome abnormality such as Down syndrome (trisomy 21), Edward's syndrome (trisomy 18), Patau syndrome (trisomy 13), Klinefelter syndrome, (47, XXY), and other chromosome abnormalities. Accomplishing that task would reduce the need for invasive amniocentesis and CVS procedures.

Inclusion Criteria:

• This study is only applicable to women who are between 8 and 30 weeks' gestation and who have been determined increased risk for fetal aneuploidy. In the interest of expediting and simplifying this study, the investigators want only women who have already decided to undergo second-trimester amniocentesis or CVS.

Exclusion Criteria:

• The only exclusion criteria are those mentioned.

The investigators anticipate enrolling 1000 subjects who are presenting for prenatal diagnosis by CVS or genetic amniocentesis for increased risk for fetal aneuploidy.