Amniocentesis is a process, which basically gets a sample of amniotic fluid, which is surrounding the fetus. The needle does not penetrate the fetus because that could potentially harm the fetus, but the use of ultrasound imaging basically aids in ensuring that the fetus is not harmed. The amniotic fluid is then grown in a culture medium for a set period of time, and analyzed for any form of disorder, or chromosomal abnormality. Most of the problems associated or found by amniocentesis are conditions that are not treatable. Genetic amniocentesis is usually done after the 15 weeks of pregnancy.

Chorionic villus sampling (CVS) is a process, which gives results even earlier in pregnancy. This involves removing and to study cells from the placenta. This has a higher rate of miscarriage as opposed to amniocentesis, but it has a distinct advantage. That significant advantage is that the results are obtained early in pregnancy. The infection rate is much higher for CVS, which poses harm for the fetus.

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Chorionic villus sampling
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