Amniocentesis is a prenatal test in which a small amount of fluid is retrieved via needle from the amniotic sac that envelops an unborn fetus so that the fetal DNA can be tested for genetic defects or chromosomal abnormalities such as Down Syndrome. It is primarily performed in women whose pregnancy may be at increased risk for these issues, since it is invasive and not without risk to the fetus. The test can also determine the sex and paternity of the child, and in some cases may be used late in the pregnancy to determine the stage of the fetus’s lung development. Typically, the test is performed at the 14-16 week mark of a woman’s pregnancy when requested by the patient or recommended by her doctor. Prior to the amniocentesis, an ultrasound is taken to locate a safe place for the needle to enter and collect the amniotic fluid. The needle is always kept away from the baby. Patients may feel some pressure but should not feel pain during the procedure, which takes approximately 10 minutes to complete.