Genetic Testing Before Pregnancy Should Be as Common as Taking Folic Acid
by Shivani Nazareth, Genetic Counselor, National Society of Genetic Counselors’ Public Policy Committee
The very first time I had to tell a patient that she was at 25 percent risk of having a baby with cystic fibrosis, she was already 16 weeks pregnant. Only a few months prior, I had graduated and passed my board exam for genetic counseling. This was a “textbook case,” as the saying goes. I reviewed the numbers with her and her husband: Odds were in their favor that this pregnancy would not be affected with cystic fibrosis. This couple wanted to know – they needed to know – with more certainty about what to expect. They were older first-time parents, and they agreed that they did not have the financial or emotional means to raise a child with a chronic health issue.
One month later, I had results of an amniocentesis to share: “DNA testing confirms the presence of two mutations, associated with a diagnosis of cystic fibrosis.” My patient screamed and cried about her results; at that point, she was nearly 21 weeks pregnant. It was one of my most difficult phone calls, and it would not be the last. Over the next 10 years of my career, DNA testing menus grew to include much more than just testing for cystic fibrosis. Expanded carrier screening for more than 100 recessive genetic diseases can now be performed quite easily. Yet, the practice of offering genetic screening to women remains largely unchanged, coinciding with the first prenatal visit – when women are already pregnant and have limited options.
While medical societies agree that preconception is the ideal time to offer carrier screening, a recent study shows that only 1 in 6 family physicians or OB/GYN providers give preconception care. Obstetricians report a desire to discuss genetics prior to pregnancy, but only one-third felt comfortable doing it. Genetic carrier screening practices vary by provider too, with some physicians following guidelines from the American Congress of Obstetricians and Gynecologists, and others following guidelines from the American College of Medical Genetics and Genomics. As the trend moves toward screening for more diseases, it makes sense that we shift the offering of carrier screening to the preconception time frame.
Allow me to share what the counseling looks like when a couple finds out about their risks ahead of time. Recently, I had a patient who learned through an expanded carrier screening panel that she and her husband were at 25 percent risk of having a baby with Wilson’s disease. Wilson’s disease results from an inability to metabolize copper, and patients who have it often present in their teenage years with vague symptoms of fatigue and jaundice. In more severe cases, they can have psychotic episodes and liver failure, at which point the damage is irreversible. My patient gathered all of this information during her planned pregnancy, and when her baby was born, a DNA test revealed a diagnosis of Wilson’s disease. Within a week, she had her child on a low-copper diet with a specialist monitoring blood copper levels routinely. The end result is that her child will not develop symptoms of the disease. In a recent conversation, she asked me, “Why isn’t everyone just tested before they get pregnant?” Good question.
To be clear, I am not of the opinion that everyone should “just get tested.” With genetic testing becoming a more integral part of medicine, I do feel that carrier screening should be universally offered in the preconception period. Some patients will decline based on personal beliefs; that is very different than not being tested due to lack of awareness. When patients who are self-proclaimed “info seekers” look to the web for guidance (as many of them do), very few pre-pregnancy checklists include carrier screening as an important health item. Pregnancy websites usually recommend folic acid before conception, but the conversation about genetic testing is altogether missing. Most of the pre-pregnancy checklists allude to genetics through a blanket statement about “researching family history.” While family history is important for many reasons, over 80 percent of children born with recessive diseases have no known family history of the condition. Many parents learn they are carriers of a rare disease only after their child is born. This was the case for Ethan Bessey, who lost his infant son to spinal muscular atrophy. He and his wife have since become fierce advocates for awareness.
So, what can we do? It seems there is a change that needs to begin with the medical community. The annual well-woman exam presents an opportunity to broach the topic of genetic testing without the stress of an ongoing pregnancy, and it gives women ample time to think about how much information they desire. The “One Key Question” initiative encourages physicians to ask, “Would you like to become pregnant in the next year?” If a patient responds, “yes,” then there is a window to insert genetics into the conversation. Ideally, this change will result in a pre-pregnancy discussion about carrier screening becoming just as ubiquitous as advising women to take folic acid.
Following carrier screening, some women use the information to consider alternative approaches to parenting, like IVF with genetic testing of embryos, sperm donation or adoption. Even when couples do not plan to change the course of a pregnancy, the benefits of knowing include optimal management of a high-risk pregnancy, preparation for possible birth complications and early intervention in the newborn period. In the case of rare conditions, like Wilson’s disease, genetic testing helps parents to avoid a potentially long and stressful diagnostic odyssey for their child. Ultimately, the choice to pursue carrier screening is a deeply personal matter, but I believe that anyone planning a family has the right to know the option is there.
Author bio: Shivani Nazareth is Director of Medical Affairs at Counsyl, a DNA testing and genetic counseling service. She worked as a clinical genetic counselor for over ten years in New York City, most recently at Weill Cornell Medical College. Shivani obtained her graduate degree from the Icahn School of Medicine at Mount Sinai and currently serves on the National Society of Genetic Counselors’ Public Policy Committee.