NIPT: More than "just a blood test"

I often hear patients elect to pursue non-invasive prenatal testing, or NIPT, as it is "just a blood test." But the thing is, it's really not. It has a purpose, limitations, and the potential to impact health management not only for your pregnancy but for yourself.

That said, my hope in writing this is to provide you with basic yet essential points to consider prior to pursuing NIPT and to encourage and enable you to think critically about what information you want from testing and ultimately what you would do with that information.

1.  Timing and Safety: NIPT is typically conducted after 10 weeks of gestation and is a safe blood test for both the pregnant person and the pregnancy itself. There's no risk associated with this screening option.

2. Nature of Assessment: NIPT analyzes placental chromosome fragments present in the maternal blood sample. These fragments contain genetic information similar, though not necessarily identical, to that of the fetus, allowing for the assessment of certain chromosomal conditions.

3. Screening vs. Diagnostic Test: NIPT is a screening test, not a diagnostic one. It evaluates the risk of specific chromosome conditions but does not provide a definitive diagnosis. A negative result reduces the risk, but it's not absolute. Similarly, a positive result doesn't confirm the condition; in the case of a positive result diagnostic testing would be recommended.

4. Scope of Assessment: NIPT, often referred to as the gender test, evaluates the risk for conditions beyond X & Y chromosomes. Labs may offer screening for various chromosome conditions though most basic panels include Down syndrome, trisomy 18, and trisomy 13. Of note, as defined by the World Health Organization, gender refers to the characteristics of women, men, girls and boys that are socially constructed. This includes norms, behaviors and roles associated with being a woman, man, girl or boy, as well as relationships with each other. As a social construct, gender varies from society to society and can change over time. So it cannot, by definition, be assessed by NIPT.

5. Possible Limitations and Unexpected Results: NIPT may yield inconclusive or unexpected results due to reasons such as insufficient genetic material in the blood sample (low fetal fraction), technical issues, increased maternal weight, or poorly timed testing. Such outcomes might have implications for your personal or pregnancy health.

My intent is not to be a party pooper and dampen the excitement of what is possibly an amazing time in your life. It's to educate and offer information so you can make the most of this amazing time.

If you have further questions about NIPT or would like to have a more comprehensive discussion, schedule an appointment with a genetic counselor today.