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With Rapid Uptake of Noninvasive Prenatal Screening, Many Question its Impact on Abortion

NEW YORK (GenomeWeb) – When Indiana passed a law in March that prohibited abortions based on fetal genetic abnormalities, proponents of the bill cited the ubiquity of noninvasive prenatal tests as evidence that women would increasingly pursue abortion to avoid having children with genetic defects. Although the law was ultimately struck down in June by a federal judge, it led many to question whether the premise that just because it is now easier to test for Down syndrome, more couples will in fact choose to terminate pregnancies.

Noninvasive prenatal screening (NIPS) has become one of the fastest adopted clinical tests. The global market for prenatal diagnostics, which includes NIPS, is expected to grow to $6.8 billion annually by 2022, from $5.35 billion in 2010.

Despite becoming available just five years ago in the US, such tests are now routinely offered to women with high-risk pregnancies nearly worldwide and are increasingly available to women with average-risk pregnancies in the US and elsewhere.

The impact that such testing will have on abortion rates, however, is not yet clear.

It's a "cause and effect loop that's not so straight forward at all," Subhashini Chandrasekharan, assistant research professor at Duke University's Global Health Institute, told GenomeWeb. "The immediate jump from yes we'll be able to detect more genetic abnormalities prenatally, and, yes, therefore more people will terminate the pregnancy, that's where I have doubts."

Chandrasekharan has researched the ethical, legal, and social issues of emerging genomic tests, including NIPS.

It also isn't clear what impact NIPS will have on broader reproductive rights and policies in the US and elsewhere. While some have argued that NIPS, which can deliver results at 10 weeks, could provide women and couples more time to make informed decisions, there is already a backlash from abortion opponents despite the fact that such prenatal genetic testing has been around for decades. Ohio is currently considering a bill that would prohibit abortions due to genetic abnormalities, and North Dakota has had such a law on its books since 2013.

Champions of NIPS say that these tests provide a risk-free, highly accurate way to screen for the genetic defects that cause Down syndrome as well as other types of chromosomal abnormalities. Unlike the diagnostic tests for these disorders, which involve sampling DNA from the placenta itself and carry a 1 percent risk of miscarriage, NIPS relies on a blood draw, poses zero risk to the fetus, and can be performed as early as 10 weeks gestation. By contrast, amniocentesis is typically performed between 15 weeks and 20 weeks gestation.

Being able to get the results of such testing earlier has benefits, too, in that it gives women and families additional time to make informed decisions about whether or not to continue a pregnancy or to prepare for the emotional and medical consequences of having a baby with Down syndrome.

Abortion rate trends

Because NIPS has only been available for five years, there is not yet data on the impact it has had on abortion. However, researchers have sought to determine whether a prenatal diagnosis of fetal Down syndrome impacts termination by estimating the number of individuals that would be expected to have Down syndrome.

Since prenatal diagnoses of Down syndrome via invasive procedures like amniocentesis or chorionic villus sampling have been available in the US for decades, such calculations are possible.

Those tests can diagnose Down syndrome as well as a number of other genetic abnormalities and have been widely accepted and adopted.

Researchers have found that although women are more likely to terminate a pregnancy due to a positive diagnostic result, not all do, according to Brian Skotko, co-director of the Down syndrome program at Massachusetts General Hospital and a medical geneticist.

Skotko's research found that there are approximately 30 percent fewer individuals with Down syndrome than would be expected based on the prevalence of the disorder. His data is from the years prior to the advent of NIPS, but said that he and colleagues planned to update their findings with more recent data when it becomes available.

Although it "wouldn't be unreasonable to hypothesize that terminations will go up" as more couples receive testing, the same results that are seen with diagnostic testing do not necessarily hold true for women who opt for noninvasive testing, Skotko said. In addition, he said that at least anecdotally, it seems that many couples choose to have noninvasive testing despite having no intention of terminating their pregnancy regardless of the result. They just want the information.

In Skotko's clinic, which has prenatal consultation, many couples who have received a positive result on a noninvasive screen do not even want confirmatory diagnostic testing. They have no intention of terminating the pregnancy and don't want to take the risk that invasive tests pose of miscarriage, Skotko said. "There's a growing number of couples who want the information in order to be ready," he said. "Knowing ahead of time helps couples prepare emotionally, intellectually, and financially."

With a lack of concrete data about how NIPS may impact abortion, other researchers have sought to find answers through patient surveys about their views on testing, reasons for seeking such testing, and how they plan to use the results of testing.

Miriam Kuppermann, professor and vice chair for clinical research in the department of obstetrics, gynecology & reproductive sciences at the University of California, San Francisco, told GenomeWeb that based on studies she has conducted, "women aren't necessarily coming into [NIPS] thinking they'll terminate."

In a study published in Prenatal Diagnosis earlier this year, Kuppermann and her colleagues surveyed 281 pregnant women about their preferences regarding testing and how they intended to use test results in order to try to figure out the most efficient and cost-effective testing strategy. Just under half of the women surveyed, 47 percent, said they intended to continue their pregnancy even if test results indicated the fetus was likely to have an intellectual disability, the researchers found.

The authors noted that their study population reflected the characteristics of women seen at UCSF, though, and were not representative of the general population. Although the women were of diverse ethnic backgrounds, most were college graduates, had private insurance, were married or living with their partner, and of a higher than average socioeconomic status.

In addition, the authors found that depending on how women intended to use test results, they differed in the types of testing they desired. For instance, although nearly all women wanted some form of prenatal testing, women who said they were more likely to terminate a pregnancy found diagnostic testing to be more valuable than other forms of testing, while women who did not intend to terminate placed a higher value on noninvasive tests.

For women who are inclined to terminate, their best strategy may be to go straight to a diagnostic test, whereas for women who do not plan to terminate, screening or NIPS may be a better first step, Kuppermann said. Given these results, she added that "it may be that women who are having cell-free DNA testing are not as inclined to terminate, so [NIPS] may not be having a big impact on termination rates."

Chandrasekharan agreed that sometimes knowledge is the primary reason couples seek NIPS. In her research, she and her colleagues have talked a lot with patient advocate organizations, and for some people the information itself is the most important, because they can plan. They can make choices with their family that take into account their finances, support system, and other factors.

For instance, "Getting an earlier diagnosis with something like a certain sex chromosomal anomaly, which may mean that the child needs cognitive, social, and behavioral interventions earlier in life, lets people seek those services before having the baby," she said. "For some, knowing that earlier is helpful."

Regardless of why women are opting for NIPS, there is some evidence that even if laws that make it illegal to have an abortion due to genetic abnormalities are passed and withstand challenges to their constitutionality, they will not have an impact on testing or abortion rates.

According to a study published in The Lancet this April that looked at trends in abortion incidence globally between 1990 and 2014, rates did not differ between countries where abortion was legal and those where it was illegal or only allowed in order to save the mother's life.

Informed consent and genetic counseling

One area where such laws could have an impact, though, is on genetic counseling, which is particularly concerning for researchers, who say that adequate counseling is critical for informed decision making.

As shown by the recent Lancet study, the legal status of abortion may not impact the rate of abortion, but it could impact how counseling is provided, said Jennifer Kerns, an assistant professor in the department of obstetrics, gynecology & reproductive sciences at UCSF, whose research focuses on patient decision-making in complicated pregnancies.

"The best informed counseling around prenatal genetic screening is a discussion between the counselor and patient about what are the various risks and what you can do with that information," she said. "Not everyone wants that information just because they would terminate a pregnancy, but if there's a law saying that you can't terminate because of a fetal anomaly, counseling would become very convoluted."

In addition, Kerns added, it is unclear who would be held responsible — the woman, the physician providing the abortion, the physician who offered the test, or the genetic counselor who discussed the test results. "Passing laws like this ends up raising a lot of questions about what's legal and what the effect is on providers," she said. "The implication is serious."

A study published by Chandrasekharan and colleagues in the Annual Review of Genomics and Human Genetics noted that the rapid routinization of NIPS is leading to challenges with informed consent of testing. Routinization can "erode careful attention to informed decision making," the authors wrote. Other researchers have noted that often patients are unaware that NIPS is not as comprehensive as other invasive prenatal diagnostic tests. Knowing which conditions the various assays test or don't test for, and whether tests are considered diagnostic or screening tools are all important pieces toward making informed decisions. But, these issues become even more complex when women are prohibited from deciding to terminate due to certain test results.

Impact on NIPS market

In some respects it's strange that there has been such a backlash against the information provided by NIPS technology given that prenatal screening and diagnostics is not new.

Kuppermann said that one reason may be due to how quickly NIPS technology has been adopted and because of how the companies market the tests. The tests themselves "aren't that different," she said. "Prenatal screening has been around for decades, but prior to NIPS the testing wasn't really marketed. People are worried about it in part because the companies are so aggressively marketing their tests."

The companies themselves either do not track the decisions patients make after getting NIPS results or did not respond to GenomeWeb's requests for comments.

But a Natera spokesperson said that NIPS provides insight that "allows families to make informed decisions about their baby’s future, which can often include identifying hospitals equipped to deliver a baby that may require special care or finding a specialist who can provide appropriate medical care to improve long-term outcomes for the child." The spokesperson also noted that NIPS is not a replacement for diagnostic testing.

Kerns said that she did not think that laws prohibiting abortion due to genetic anomalies would impact the NIPS market because they would likely be relatively easy to circumvent and difficult to enforce.

"The jury is still out on whether people will stop having NIPS if termination is not an option," Kuppermann added. "But, that will be a really important piece of research to do."