Things to consider
If blood tests indicate your baby is at increased risk of a birth defect, your doctor will follow up with additional tests. These tests include:
- High-resolution ultrasound: This also called a level II ultrasound. It provides more detail about possible birth defects. It can check your baby’s age, brain, spinal cord, kidneys, and heart. It is usually completed between 18 and 22 weeks of your pregnancy.
- Chorionic Villus Sampling (CVS): This is an invasive test. Your doctor will collect a tiny piece of the placenta, called chorionic villus. It is checked for chromosomal or genetic disorders. A CVS test is offered to people who received an abnormal result on a first trimester screening test. Also, it is offered to people who could be at higher risk. It is completed between 10 and 12 weeks of pregnancy.
- Amniocentesis: This is an invasive test. Your doctor will collect a small amount of amniotic fluid from the area around the baby. It is tested for certain proteins. This can determine whether your baby has Down syndrome or other genetic problems. It is recommended for women who had an abnormal pregnancy screening blood test. It is completed between 15 and 18 weeks of pregnancy.
Most diagnostic tests are offered to people with higher risk pregnancies. This includes people who are 35 years of age or older, people who have had a previous pregnancy affected by a birth defect, people who have chronic diseases such as lupus, high blood pressure, diabetes, or epilepsy, or people who use certain medications.
If your doctor discovers a birth defect during the pregnancy or at birth, they may refer you to a genetic counselor. This is an expert who can explain the test results, order additional testing, and refer you to a doctor who specializes in high-risk pregnancy or genetic conditions.
Other considerations
- Pregnancy screenings are a personal choice. If your screening is abnormal (positive), do you want to take the next step? This would be a diagnostic test. Will it affect how you handle your pregnancy?
- Some screenings produce false-positives. This means your baby may not actually have a birth defect. A false-positive may or may not affect your choices for additional tests or cause stress. If a screening is normal, it can give you peace of mind.