How is prenatal genetic screening different from prenatal diagnostic testing?

Prenatal genetic screening and prenatal diagnostic testing serve different purposes in assessing the health of a developing fetus.

Prenatal Screening

Screening tests are generally noninvasive and are used to assess the likelihood or risk that a fetus may be affected by certain conditions, such as chromosomal abnormalities or structural defects. These procedures typically include maternal blood tests, which measure specific proteins and hormones, and ultrasound examinations. Because screening only identifies an increased risk rather than confirming a condition, abnormal results often warrant further investigation.12

Prenatal Diagnostic Testing

Diagnostic tests are used to confirm the presence or absence of a specific disorder when screening indicates an increased risk. These procedures are generally more invasive, as they typically require the collection of fetal cells or DNA through methods such as amniocentesis or chorionic villus sampling. While diagnostic tests provide more definitive information, they carry a higher risk of complications, including an increased risk of miscarriage.12

Ultimately, while screening helps identify pregnancies that may require closer monitoring, diagnostic testing provides the definitive data necessary for parents and medical professionals to plan for a baby’s care or make difficult reproductive decisions.1