Genetic Screening & Testing
We consult with the Maternal Fetal Medicine doctors at Platte River Perinatal Center, associated with the University of Colorado, for Nuchal Translucency Ultrasounds and extensive genetic evaluations.
The decision to have genetic screening performed is a personal decision. If an abnormality is identified, diagnostic testing (Amniocentesis or CVS) may be recommended. The information gained though this testing can help patients make informed decisions regarding the pregnancy itself, delivery planning and postpartum care.
What is the difference between screening and diagnostic tests?
There are various methods to screen for genetic abnormalities. Screening provides a risk assessment based on markers for genetic abnormalities. The benefit of screening over diagnostics is that screening is non-invasive, whereas diagnostics require an invasive procedure that, though extremely low, has the potential to harm the pregnancy.
What are the different screening tests?
1. SEQUENTIAL SCREEN
Part 1: 11 weeks to 13 weeks 6 days – Ultrasound and blood test
An ultrasound is performed to evaluate the Nuchal Translucency, or the thickness of the baby’s neck, which is associated with certain genetic and cardiac abnormalities. The ultrasound also looks for early signs of other major abnormalities in the brain, intestines, heart and neural tube. A blood test for two analyses (chemicals) is also done, which gives an overall risk assessment for Down Syndrome, Trisomy 18 (Edward’s Syndrome) and 13 (Patau Syndrome).
Part 2: 15 to 22 weeks – Blood test only
This is a blood test for four analyses (chemicals). This result in conjunction with part 1, gives the risk for Down Syndrome, as well as, neural tube defects and other rare but very serious genetic abnormalities.
Screening Parts 1 and 2 have a 93% detection rate for Down Syndrome and 2.5% false positive rate. Part 1 alone has an 87% detection rate and 5% false positive rate (slightly higher chance of missing an abnormality, or falsely identifying one that does not exist).
2. QUAD SCREEN: 15-22 weeks – blood test only
This is Part 2 only of the sequential screen and has an 81% detection rate of genetic abnormality and neural tube defect.
3. CELL FREE FETAL DNA
Blood test from 10 weeks on
- 99% detection rate of genetic disorders including Down Syndrome, Trisomy 13 and 18 and sex chromosome abnormalities (Kleinfelter and Turner Syndromes).
- The false positive rate depends on your risk level. If you are low risk (age <35, have no family history of genetic abnormality and your other screening tests are negative) you actually have a higher rate of false positives (getting a positive result in a normal pregnancy).
- This test is best for high risk individuals, however, it is available to everyone. High risk: age >35, have a family history of genetic syndrome and other screening tests came back positive.
- Genetic screening may be covered by insurance. Progenity offers the Peace of Mind Program. They will file each claim with insurance and will call before sending a bill. You can call (855) 209-1228 with any questions regarding insurance coverage. Unfortunately, the Colorado Women’s Health Center office will be unable to answer any financial questions about genetic screening coverage.
4. ANATOMY ULTRASOUND
Recommended for all patients weeks 18-22
This ultrasound looks at all the parts of the baby and can identify malformations that may be associated with a genetic syndrome, as well as, other sporadic malformations not associated with a syndrome. Identification of malformations can aid in decision making about the pregnancy and help guide delivery planning and postpartum care.
What is carrier screening and how is it different from genetic screening?
Genetic screening as described above screens the baby’s genetics. Carrier screening looks at the maternal genetics. If you carry the gene for a disease like Cystic Fibrosis or Tay Sachs and your partner does as well, there is a risk that your child could be affected by the disease. Even if there is no family history of the disease, you still may be a carrier of the abnormal gene. If the maternal screen is positive for an abnormal gene then we screen the father. Genetic screening may be covered by insurance.