Why is next-generation sequencing used in NIPT?

During pregnancy, the blood sample contains DNA fragments released from the placenta. Sequencing reads many fragments and helps estimate whether there is an unusual amount of genetic material from selected chromosomes. This makes it possible to screen without collecting a sample directly from the pregnancy. NIPT is a screening test, so a higher-chance result does not confirm a chromosome condition. A lower-chance result cannot rule out every genetic or structural difference.

The laboratory process focuses on the chromosome findings included in the particular NIPT service. Results can be affected when the sample contains too little placental DNA, when the pregnancy has more than one fetus, or when there are biological factors that make interpretation difficult. The report may therefore say that a result is unavailable and a repeat sample or another test may be discussed.

Before testing, ask what chromosome findings the panel examines, when the sample can be taken, and how an unclear result is handled. After testing, review the report with your maternity clinician or a genetics professional. If the result indicates a higher chance, they can explain diagnostic options such as a targeted procedure and how its information differs from screening. Do not make decisions about the pregnancy from the screening report alone.

Contact your maternity team promptly if the report shows a higher chance, cannot provide a result, or conflicts with an ultrasound finding. The next step depends on the result, gestational stage, ultrasound picture, and your preferences. Seek urgent pregnancy care for heavy bleeding, severe abdominal pain, fainting, or fluid leakage; NIPT itself does not assess these symptoms.

Ask which chromosomes and conditions are included, whether the result is a screen or a diagnosis, and what follow-up test would clarify an unexpected finding. You can also ask how an insufficient sample affects interpretation and when the result will be available.