Understanding Prenatal Genetic Screening Tests

Every pregnant woman getting proper medical care will undergo certain prenatal tests, but some testing is a matter of choice, not necessity. Obstetrician and author Dr. Keith Eddleman explains prenatal testing and genetic screening.

How to understand pre-natal testing:
Pregnant women are faced with dozens of decisions before the baby comes, including which of a barrage of tests to take. Which tests should you undergo? 

- Your doctor will help you determine which tests you need at your first prenatal visit. Some are standard for all women, while others are appropriate for your personal situation.
- The most common tests are for cystic fibrosis, diabetes and a routine ultrasound to check for fetal abnormalities.
- Other tests are recommended for people of certain ethnic backgrounds, which have particular susceptibilities to specific diseases.
- Most tests are taken by drawing blood.
- One early screening test for chromosomal abnormalities (such as Down's Syndrome) is performed by drawing blood in conjunction with doing an ultrasound.
- Chromosomal abnormalities increase with maternal age. As such, women over the age of 35 are routinely given an amnio (amniocentesis) to find such abnormalities.
- After reviewing your genetic history your doctor may recommend more invasive testing.