“The Gradual Trap”–Informed Consent Process: Understanding

In the first post on the Informed Consent Process, I discussed the element of voluntariness. This week’s post concerns the element of “understanding” and is prompted by the recent ACOG guidelines on NIPT and an article from this Spring that introduced the notion of “the gradual trap” in the context of prenatal testing.

As a reminder, the new ACOG guidelines on NIPT recognize NIPT as a valid testing method for those women considered “high-risk.” Many, if not most, of those women will meet that standard after accepting first- or second-trimester screening testing. Like NIPT, screening tests simply provide a recalculation of whether a pregnancy is carrying a fetus with Down syndrome. These tests have no risk of miscarriage, like diagnostic tests, but, as ACOG reiterated even for NIPT, screening tests are not diagnostic. Therefore, in order for a mother to truly know whether her developing child has Down syndrome, she still must accept the risk that knowing could result in a miscarriage from the needle entering the womb for diagnostic testing.

Screening tests have been around since the 1980’s and involve probabilities. An expectant mother has a baseline probability of having a child with Down syndrome associated with her age: the older the mother, the greater the chance. Screening tests began with tests of the mother’s blood typically performed in the second trimester. Until NIPT, the most recent development in Down syndrome prenatal testing had been the combination of an ultrasound measurement of the back of the fetus’ neck near the end of the first trimester (this test is called the Nuchal Transluscency test) to provide a recalculation. Between the combined test in the first trimester and the Quad test in the second trimester, there evolved several different testing combinations, e.g. sequential, contingent step-wise, integrated, where the first- and second-trimester test results are analyzed to provide a new probability calculation. Indeed, the still-governing ACOG practice guidelines recognize that “ideally” integrated screening testing should be offered prior to being termed “high-risk,” as integrated screening tests return the most accurate screening results.

Much of the research on the actual administration of prenatal testing comes from countries outside the United States. This, therefore, leaves the assessment of how well prenatal testing is being administered in the United States unknown. But, the studies from other countries raise valid issues that should inform the element of “understanding” for informed consent.

Several studies have found that women undergoing prenatal testing do not understand the prenatal testing results. ACOG recognized this in its practice bulletin recommending the offering of prenatal testing to all patients, noting that test results should not be delivered as a “positive” or “negative,” since that is how they are commonly misunderstood, but rather as a probability re-assessment. This is not meant as a criticism of expectant patients ability to understand the test results and it should not be surprising given that ACOG fellows have admitted their training on prenatal testing for Down syndrome is “barely adequate” or “non-existent.” Moreover, fundamentally, humans in general, including medical professionals, have difficulty understanding probabilities and explaining probabilities to others.

Further, it has been found that patients do not understand that agreeing to one round of prenatal testing will result in their being asked to agree to a later round, and, ultimately, if they receive a diagnosis, be confronted with the decision of whether they will terminate their pregnancy. Despite the ACOG guideline on prenatal testing making it mandatory that OBs discuss the option of termination following a diagnosis, half of women in another study said they did not anticipate being confronted with that decision when they simply accepted the “no-risk” prenatal screening test.

It is this lack of understanding over the course of prenatal testing that caused researchers this Spring to characterize the prenatal testing experience as “a gradual trap“:

• An expectant mother is offered a screening test that has no risk of miscarriage–even part of it can be done during the ultrasound she already wants to have to see her baby;
• When that screening test returns a higher probability, she is offered diagnostic testing, or, now, NIPT;
• When the NIPT returns a higher probability, she is then offered genetic counseling (note not beforehand) and offered diagnostic testing, which poses a risk of miscarriage that she did not expect; and, then,
• When a diagnosis is returned, she is asked if she wishes to continue her pregnancy, because the OB must counsel her about termination per ACOG guidelines.

An inertia develops: if you accepted prenatal screening, it was because you wanted to know; now that a higher probability is suggested, shouldn’t you want to know for sure through diagnostic testing; and, then, once you know for sure, as the window is closing for accessing abortion services, the patient is counseled about terminating her pregnancy. Hence, the phrase “the gradual trap.”

This phenomenon of a process predicated on simply providing information but being conducted with a pervasive lack of understanding is not new–women have reported their confusion about test results since the advent of screening testing. And, yet, the guidelines by emphasizing the need for the patient to make an informed choice presume that by simply saying it should be so, then it can be trusted to actually happen that way.

The issue of understanding goes beyond understanding the testing protocol itself, as it also involves understanding what in fact is being tested for. That will be picked up in a later post. For now, here’s this post’s question:

Question: What was your experience with prenatal testing? Did you understand the path you would be entering when considering the first offering of prenatal screening testing?