The Why, Not The How, Of Prenatal Testing

Throughout the last 50 years or so, many prenatal testing options have become available, the two most common being amniocentesis and chorionic villus sampling (CVS).These allow for a woman or a couple to determine certain health issues of an unborn baby. Prenatal testing will never guarantee a healthy child, as many genetic disorders and birth defects are either not testable with our current technology or we would not have prior knowledge that we should test for them. When I first worked with a prenatal population, in the early to mid-1990s, I was quite surprised and frustrated by some of my patients' assumptions that this type of testing could provide answers to far more questions than it actually could. I had patients who would say to me "I heard an amniocentesis can rule out 342 diseases" (the number is made up).

Once I was pregnant, and reading What to Expect When You're Expecting, I figured out where the number came from. The book was very helpful for many pregnancy related questions, but I found that section misleading. I knew what they were getting at. I knew they meant that perhaps, if one tested for 342 specific diseases, amniocentesis would be capable of ruling them out. However, I've never met a patient who had a family or personal history of 342 different diseases! Amniocentesis was then and is now used to rule out chromosome abnormalities, such as Down syndrome, as well as single-gene disorders if there is a reason to be concerned that they might present in the fetus. We might be concerned about a single-gene disorder if there is a family history, or if both parents have been found to be a carrier of this disorder. Even then, we need to be aware of the specific gene alterations to look for. It's not as simple as just do a test and make sure everything is fine.

Many patients, friends, and family members have asked me over the years why a person would consider having prenatal testing if she would not consider terminating an affected pregnancy. It's a very good question, with a somewhat complicated answer.

Janice Berliner, 2019

Many patients, friends, and family members have asked me over the years why a person would consider having prenatal testing if she would not consider terminating an affected pregnancy. It's a very good question, with a somewhat complicated answer. There are certain congenital defects, such as spina bifida (a hole in the column that contains the spinal cord) that will have better outcomes if the baby is delivered by C-section. When there is a hole in the spinal column, and the baby goes through the birth canal, there is more likely to be an infection and complications. So if it is known ahead of time that the baby has spina bifida, and the woman or couple opt to continue the pregnancy, then they will know that a C-section is recommended over a vaginal delivery.

Additionally, for many types of special needs, it is extremely beneficial to initiate infant stimulation programs, occupational therapy, physical therapy, speech therapy, etc. as soon as possible after birth. Some of these services and programs have waiting lists, and if it is known that the baby has a disorder for which they would be helpful, the parents can put themselves on the waiting list prior to the birth, saving valuable time after.

Perhaps the most crucial reason to have the information prior to the birth of the baby involves the emotions and relationships of the family members into which this child will be born. Consider what it would feel like to have a baby with special needs or a life-threatening illness. Hearing that news upon delivering your child is enormously shocking and devastating. Being able to process some of this shock and devastation prior to the baby's birth allows for bonding and acceptance.

It seems to me that the first question everyone asks upon the birth of your child is "is it a boy or girl?" Perhaps the question might be "is everything okay?" I don't know about you, but if I were to deliver a child with some kind of difference, I would find it difficult to answer those questions. I might find myself saying "well it's a girl, but there's a problem." And consider if the baby's sex is actually not clear at birth. How would you answer that question? Wouldn't it be easier to be able to think about that ahead of time, so that the answer reflected your thoughts and feelings on the subject? Thinking some of this through before the birth allows for some joy in the delivery room and some preparedness. The parents have the opportunity to do research, speak with doctors, friends, family, and even perhaps join a support group. This way when the baby is born, they are prepared as best they can be, with few surprises. I don't mean to imply that it's all rosy and everything is now easy, but I think it is easier.I also certainly do not mean that there can't be overwhelming joy in delivering any baby, with any conditions or differences. I only mean that avoiding surprises can make things more joyful.

A woman named Emily Perl Kingsley wrote a beautiful piece many years ago when her child was born with Down Syndrome. It is entitled Welcome to Holland (, where she poignantly describes the emotional roller coaster that is having a child with special needs. She poetically points out that while this is not the child you expected, there are still beautiful and wonderful things about this child that you would never have known about otherwise. Please take a few minutes to read this article, and have a handful of tissues at the ready. I have never gotten through it without crying, but I promise you it is worth the read.

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