What testing is available for older moms to diagnose chromosomal abnormalities?
Expectant moms over the age of 35 are at an increasing risk for giving birth to a child with a chromosomal abnormality, such as Down Syndrome. Traditionally, women of Advanced Maternal Age (AMA) have been offered either Chorionic Villus Sampling (CVS) or an amniocentesis. Both of these tests will diagnose 99.9% of chromosomal abnormalities. However, they also have about a 1/300 chance of miscarriage. There is now a non-invasive screening test available. This test is a combination of an early ultrasound to measure the Nuchal Translucency (a fluid collection behind the neck of the baby) and a maternal blood test. This testing can be performed between 11 and 14 weeks of gestation and will detect 90% of babies with Down Syndrome with only a 5% false-positive rate. Additionally, the test will identify 40% of serious heart defects. Moms with a positive screening test may then choose to have an amniocentesis, knowing that the benefits of doing so will probably outweigh any risks. Academy Wome
