New non-invasive prenatal testing methods appear to be safer, but there are complex questions to address
Last revised: December 2015
Every year, approximately 10,000 women in Canada have an amniocentesis — a prenatal procedure in which a sample of amniotic fluid is drawn by needle and tested for chromosomal abnormalities such as Down syndrome. This type of screening carries a risk. Up to 70 pregnancies are lost each year from the complications that may occur.
Advances in genomics have led to the development of non-invasive prenatal testing (NIPT) that can screen for Down syndrome and two other genetic diseases by analyzing fragments of fetal DNA found in maternal blood. “It would be nice for women to have the safest test possible, with the highest performance and lowest risk to pregnancies,” says Dr. Sylvie Langlois, a University of British Columbia medical geneticist and co-leader of the PEGASUS (Personalized Genomics for Prenatal Aneuploidy Screening Using Maternal Blood) project. “That’s what NIPT has the potential to do.”
In addition to comparing the accuracy and cost-effectiveness of two different methods of DNA analysis, PEGASUS is also exploring the ethical, legal and social questions that surround this research, and the implementation issues that health-care practitioners could face. It is important to provide doctors, patients and policymakers with the information they need to discuss the pros and cons of NIPT, according to project leader Dr. François Rousseau, a medical biochemist at Université Laval. Currently, NIPT is only publicly funded in certain circumstances.
“We need to be sure that our research is giving the people who are picking up the ball downstream the high-quality evidence and tools they need,” says Dr. Rousseau, explaining how an emphasis on GE3LS (Genomics and its Ethical, Environmental, Economic, Legal and Social Aspects) was woven into PEGASUS from the start.
The ethical considerations around NIPT include a concern that women may feel pressure to test, and the prospect of families facing an avalanche of complex genetic data if the range of information that can be detected expands to include predisposition to other conditions, says PEGASUS researcher Dr. Vardit Ravitsky, a professor in the Université de Montréal’s Department of Social and Preventive Medicine.
Yet NIPT could “revolutionize prenatal care,” adds Dr. Ravitsky. If women are able to test in the first trimester, they will have more time to make an informed, early choice about the outcome of their pregnancy or to prepare for the birth of a child with special needs.
Personalized health has the potential to transform the way health care is delivered in Canada, including improvements in clinical practice, better treatment and outcomes for patients, and a more efficient, cost-effective, health-care system. The development of non-invasive prenatal testing, currently for three genetic diseases, will reduce risk for women posed by traditional testing technologies, improving their quality of care.
“As a test that can be performed early in the pregnancy and without any risk to the fetus, NIPT is revolutionizing prenatal care.”
— Dr. Vardit Ravitsky, PEGASUS researcher