What Is Prenatal Carrier Screening?

Learn what prenatal carrier screening is, how it works, who should consider it, and what conditions it can detect before or during pregnancy.

Prenatal carrier screening is a blood or saliva test that checks whether a person carries a gene change for certain inherited conditions. A carrier usually has no symptoms but can pass the gene change to a child. If both parents are carriers of the same condition, the child has a higher chance of being affected.

The most common carrier screening panel looks for spinal muscular atrophy (SMA), fragile X syndrome, and cystic fibrosis. Expanded panels can screen for dozens or even hundreds of conditions at once. Screening can be done before pregnancy or during the first or second trimester.

The American College of Obstetricians and Gynecologists (ACOG) recommends that all people who are pregnant or planning pregnancy be offered carrier screening for cystic fibrosis and spinal muscular atrophy. Fragile X carrier screening is recommended for people with a personal or family history of fragile X-related disorders or intellectual disability.

Carrier screening does not diagnose a condition in the baby. It only tells you whether a parent carries a gene change. If results show a risk, a genetic counselor or maternal-fetal medicine specialist can explain follow-up options such as diagnostic testing during pregnancy.

Most samples are collected at a CLIA-certified lab by blood draw or saliva kit. Results are usually ready within five to ten business days. Many labs allow you to order the test online and visit a local collection site.

References

• American College of Obstetricians and Gynecologists (ACOG). Carrier Screening FAQ. https://www.acog.org/womens-health/faqs/carrier-screening
• Centers for Disease Control and Prevention (CDC). Family Health History and Genetics. https://www.cdc.gov/genomics/famhistory/index.htm