Summary of California Prenatal Screening Tests
During your pregnancy, your prenatal care provider should offer you two prenatal screenings as part of the California Prenatal Screening Program. Each screening requires you to give a blood sample. Each screening estimates the chances of your fetus having one of the genetic conditions or birth defects screened for in the Prenatal Screening Program.
Below are the details about the two types of prenatal screening offered by the state program.
Cell-free DNA (cfDNA)Screening
What it screens for: Genetic conditions
Cell-free DNA (cfDNA) screening of your blood sample uses genetic information from the placenta to check the fetus for the chances of it having the genetic conditions below. The placenta is the organ inside a pregnant individual that provides nutrients and oxygen to the fetus.
- Trisomy 21 (Down syndrome)
- Trisomy 18 (Edwards syndrome)
- Trisomy 13 (Patau syndrome)
When to get it: cfDNA screening is recommended from 10 weeks to the first day of 21 weeks of pregnancy. The screening can be done after the first day of 21 weeks of pregnancy but the follow-up services are then more limited. Screening results are available in 10 to 14 days.
Maternal serum alpha-fetoprotein (MSAFP) screening
What it screens for: Neural tube defects
Maternal serum alpha-fetoprotein (MSAFP) screening of your blood sample looks at the protein made by the developing fetus. The amount of the protein may show whether the fetus has a birth defect called a neural tube defect. The most common types of these defects are:
- Open spina bifida (opening in the spine)
- Anencephaly (missing parts of brain or skull)
When to get it: SAFP can be done from 15 weeks to the first day of 21 weeks of pregnancy. Screening results are available in 7 to 10 days.
After Prenatal Screening
Most pregnancies result in a healthy baby. But 3 or 4 out of 100 fetuses may have a genetic condition or birth defect.
If prenatal screening finds an increased chance of your fetus having one of the genetic conditions or birth defects screened for, your prenatal care provider should offer you the option of getting genetic counseling, an ultrasound exam, and diagnostic testing to learn more about whether your fetus has the birth defect. Diagnostic testing includes chorionic villus sampling (CVS) and amniocentesis.
If prenatal screening finds no increased chance of your fetus having one of the genetic conditions or birth defects screened for, no further services will be offered by your prenatal care provider from the state program.