Amniocentesis, Chorionic Villus sampling, and Cordocentesis
Amniocentesis is the sampling of detached embryonic cells floating in the amniotic fluid. After a small amount of the fluid is extracted through a needle, tests are made to determine whether any chromosomal abnormalities or fetal infections are present. The test can also be used to determine the sex of the baby.
Similar to amniocentesis, CVS can be used to check for chromosomal abnormalities by taking a tissue sample of the placental tissue, and can usually be performed as early as 10 weeks of gestation.
Cordocentesis is the sampling of blood from the fetal umbilical cord.