Prenatal testing provides information about your baby's health before he or she is born. Testing is available to pregnant women Who are aged 35 or older, because they are at higher risk for having a child with a chromosomal abnormality Who have a family history of an inherited condition such as Duchenne muscular dystrophy When their ancestry or ethnic background means that they might have a higher chance of an inherited disorder such as sickle cell anemia , thalassemia or Tay-Sachs disease To screen for common genetic disorders such as spina bifida and Down syndrome Two diagnostic procedures are common in prenatal testing. Amniocentesis involves testing a sample of amniotic fluid from the womb. CVS (or chorionic villus sampling) involves taking a tiny tissue sample from outside the sac where the fetus grows.