What you can expect

Depending on the type of test, a sample of your blood, skin, amniotic fluid or other tissue will be collected and sent to a lab for analysis.

• Blood sample. A member of your health care team takes the sample by inserting a needle into a vein in your arm. For newborn screening tests, a blood sample is taken by pricking your baby's heel.
• Cheek swab. For some tests, a swab sample from the inside of your cheek is collected for genetic testing.
• Amniocentesis. In this prenatal genetic test, your doctor inserts a thin, hollow needle through your abdominal wall and into your uterus to collect a small amount of amniotic fluid for testing.
• Chorionic villus sampling. For this prenatal genetic test, your doctor takes a tissue sample from the placenta. Depending on your situation, the sample may be taken with a tube (catheter) through your cervix or through your abdominal wall and uterus using a thin needle.