Is Non-Invasive Prenatal Screening the “Holy Grail” of Prenatal Testing?

In her recent blog post at the Huffington Post, Dr. Anne Drapkin Lyerly, a doctor who chaired ACOG’s ethics committee, says she has found the “Holy Grail” of prenatal testing in Non-Invasive Prenatal Screening (NIPS). Is she correct?

The knowledge I have about the Holy Grail is limited to just two movies. It has legendary powers of healing, as demonstrated by Indiana Jones using it to heal his father in The Last Crusade. And, it was the subject of knights’ quests, as documented in Monty Python and the Holy Grail.

But does it apply to NIPS as described by Lyerly?

Lyerly shares that she is in her second pregnancy since turning 40, an age when the chance for having a child with Down syndrome increases. She “craves reassurance.” Lyerly further shares how familiar she is with the pain of miscarriage, particularly when it is the result of invasive diagnostic testing, having run a miscarriage clinic herself.

NIPS has a high specificity rate, the ability to determine what pregnancies are not positive for Down syndrome. Expectant moms, particularly those over 40 like Lyerly, can receive a measure of reassurance through a negative NIPS report. They can decide to rely on the low false negatives of NIPS to forgo the risk of invasive testing and its risk of miscarriage. Lyerly calls this “a gift.” Her treating OB said to her:

You know Annie, this is the Holy Grail. It’s what we’ve been waiting for all these years.

But, does that description apply for a positive NIPS result?

Lyerly writes of:

• How she kept her pregnancy a “secret.”
• How one of NIPS’s benefits is that it can return results early enough in a pregnancy that “even a mother of four can hide a protruding belly.”
• How one of the concerns with NIPS is patients relying on a false positive to have “unnecessary abortions of healthy fetuses.”

Lyerly’s writing refers to Down syndrome in connection with phrases like a “genetic problem,” “a chromosome problem,” “an affected child.” All of this language suggests the alternative following a positive NIPS result for Down syndrome: an abortion that Lyerly would not consider “unnecessary.”

Here is why Lyerly’s description of NIPS as the Holy Grail is confusing. Because in the very first paragraph, Lyerly says:

there is one thing that I don’t want to live with: even a whisper of a sense I had something to do with ending the life of my child-to-be.

If that is the case, then why the tentativeness until receiving a negative NIPS result? Why only then settle in to the fact that she was going to have a baby unless the alternative is true? That had the test been positive, she would not be having a baby. And how does that square with not wanting to have done something that would end the life of her child-to-be?

I do not want to presume that in Lyerly’s case termination would have inevitably followed from a positive NIPS result confirmed through invasive testing. She even writes of how following a positive NIPS result, a second-trimester ultrasound could then be used to identify most conditions, thereby avoiding the risk of miscarriage from invasive testing. But, her post’s headline and touting of NIPS as the “Holy Grail” must be limited to having only that title applied if a mother is seeking reassurance and receives a negative NIPS result. And, if that is the case, then how can it be called the Holy Grail?

If the Holy Grail is to avoid risking a miscarriage through invasive testing, then NIPS is not the Holy Grail if it returns a positive result. As Lyerly (and every other medical society statement) says, a positive NIPS result should be confirmed through invasive testing prior to making a decision to terminate. So NIPS does not eliminate that risk of miscarriage (if anything, it may increase it).

Further, by Lyerly’s statements, NIPS cannot be considered the Holy Grail depending on what else it reports back to the parents.

As Lyerly ends her blog post, she confidently informs her four boys after her NIPS result that they are “getting a sister.” This is because NIPS can also detect the sex of the fetus and Lyerly’s report showed “No Y chromosomal material detected.” Therefore, expectant mothers can avoid the risk of miscarriage and find out the most selected-against genetic condition: sex, specifically female.

Surely, in this sense, Lyerly does not consider NIPS the Holy Grail of prenatal testing. Earlier in her post, Lyerly describes sex selection as a “dubious purpose” for NIPS. Moreover, she chaired ACOG’s ethics committee when it issued its statement that using prenatal testing for sex selection was unethical.

So, given her own statements that would not support characterizing NIPS as the Holy Grail in the case of a positive result or for the dubious purpose of sex selection, can it really be called that? The Grail wasn’t Holy only sometimes.