Diagnostic Tests


Prenatal dagnostic tests can diagnose or rule out certain types of birth defects and genetic disorders with certainty. However, there is a small risk of miscarriage associated with these tests.
 
Diagnostic tests are offered to women at an increased risk for certain birth defects and women who will be age 35 years or older at the time of delivery. Diagnostic tests are available to women of all ages at your request.
Tests Cell Free
Fetal DNA in Maternal
Blood
Chorionic
Villus Sampling
(CVS)
Amniocentesis
Time Frame At Least 10 weeks 10 to 12 weeks Usually 15 to 20 weeks
Method Blood sample fromt he mother's arm Biopsy of placenta Sampling of amniotic fluid
What It Detects and Detection Rates Trisomy 13 (>90%), 18, and 21 (nearly 100%); gender Specialized genetic testing, chromosome abnormalities and miscarriage (nearly 100%) Specialized genetic testing, chromosome abnormalities and miscarriage (nearly 100%)
Risk None 0.3% - 1% miscarriage risk 0.3% - 0.5% miscarriage risk
Results Available Varies Varies Varies