What is a genetic screening test?

A screening test places healthy women in a high or a low risk category for a fetus with a disorder. For example, Down syndrome is one of the most common forms of developmental delay and the risk increases for older women. However, 80% of Down syndrome occurs in younger women with no risk factors. Prenatal screens help to detect this disorder. Now, we screen for fetal Down syndrome very effectively, by measuring the thickness of the fluid in the fetal neck at 11 weeks and combine this with a blood test. A high risk result can mean earlier detection of Down syndrome for all types of reproductive planning.

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Why do women seek genetic services?

  1. Because of a family history of a medical disease or birth defect either in their family or because they have a previous affected child.
  2. Because they are older and are concerned about risks that increase with maternal age.
  3. Because they were found to carry a pregnancy with a birth defect and need complete diagnosis and a coordination of care prenatally, at delivery, and in the neonatal period. About 2-3% of all fetuses have a serious birth defect.
  4. Because they want to be screened for birth defects and genetic conditions.
  5. Because they are at sufficient risk for a child with a disorder and they want definitive diagnostic testing. Example: CVS, Amniocentesis
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What types of early pregnancy screening are available?

All women are offered screening for fetal Down syndrome, open fetal defects, cystic fibrosis, and HIV screening. All are optional.

Other types of screening are done for patients whose ethnic background places them at higher risk for a genetic disorder. For example, Sickle Cell screening in an African American couple.

How to prevent birth defects?

  • Take vitamins before pregnancy (a multivitamin will do) even if you are not planning to become pregnancy (50% of pregnancies in the United States are unplanned).
  • Stop smoking or drinking
  • If you have a medical condition such as a seizure disorder or diabetes, get seen before pregnancy or early in pregnancy
  • Obtain prenatal care.

Resources for Patients

Maternal-Fetal Medicine Program at LDS Hospital – 801.408.3466


MotherToBaby is dedicated to providing evidence-based information to mothers, health care professionals, and the general public about medications and other exposures during pregnancy and while breastfeeding.


KidsHealth is the largest and most visited site on the Web providing doctor-approved health information about children from before birth through adolescence.

March of Dimes

Our mission is to improve the health of babies by preventing birth defects, premature birth, and infant mortality. We carry out this mission through research, community services, education and advocacy to save babies’ lives. March of Dimes researchers, volunteers, educators, outreach workers and advocates work together to give all babies a fighting chance against the threats to their health: prematurity, birth defects, low birthweight.