Womens Services

Prenatal Diagnosis

Diagnostic Testing

Legacy Maternal-Fetal Medicine offers tests that can specifically discover if a fetus has a certain problem such as Down syndrome. We can test for many things besides Down syndrome, but these specific tests are reserved for those couples that have a known risk for the specific condition. If you are in a risk group or in a situation for which a diagnostic test may be indicated, detailed counseling will help you understand your risks and options.

Some of these tests are "invasive" and do carry a small risk for pregnancy loss. If you have questions about whether prenatal diagnosis is right for you, please talk with your healthcare provider.

Criteria

Women who meet one or more of the following criteria may want to consider prenatal diagnoses by amniocentesis or CVS:

  • Have had a previous pregnancy with a chromosome abnormality (e.g. Down's syndrome)
  • Are a carrier of a known chromosomal disorder. This also applies if the father is a carrier.
  • Have had a triple marker maternal serum screening test result indicating an increased risk for chromosomal abnormalities
  • Are concerned about age-related risks because the risk of some chromosomal disorders increases with maternal age
  • Are a carrier of sex-linked diseases, such as hemophilia or muscular dystrophy
  • Have a family history of birth defects
  • Are carriers of single gene disorders that can be detected prenatally

Amniocentesis

Amniocentesis is taking a sample of the fluid around the fetus by inserting a thin needle. Ultrasound is used to guide the needle during the entire procedure. The fluid is then tested and the cells are cultured in the lab to give the results. The test is typically performed between 15 and 20 weeks gestation.

Chorionic villus sampling (CVS)

CVS is a sampling of the developing placenta. It is either done through the cervix (with a catheter) or through the abdomen (with a needle). Ultrasound is used throughout the procedure to guide the instrument. The test is typically performed between 10 and 13 weeks gestation. With experienced physicians, the procedure related risk is equal to that of an amniocentesis.