Methods and Effects of Prenatal Genetic Testing
Outline:
I. Introduction
II. Methods of Genetic Testing
III. Case studies
IV. Effects of prenatal genetic testing
V. Conclusions
VI. Works Cited
I. Introduction
Prenatal genetic testing has become one of the largest and most influencial
advances in clinical genetics today. "Of the over 4000 genetic traits
which have been distinguished to date, more than 300 are identifiable via
prenatal genetic testing" (Morris, 1993). Every year, thousands of
couples are subjecting their lives to the results of prenatal tests. For
some, the information may be a sigh of relief, for others a tear of terror.
The psychological effects following a prenatal test can be devastating,
leaving the woman with a decision which will affect the rest of her life.
For couples with previous knowledge of genetic disorders in their family
and concerned parents, prenatal genetic testing is part of the regular pregnancy
checkup. Making an appointment with a genetic counselor may seem strange
or even frightening for some, still others view it a very common step being
taken by many Americans today.
The desire to have a "normal" child is held by every parent and
only now are we beginning to have the ability to select for that child.
In preparation to receiving genetic testing, the parents are required to
meet with a genetic counselor. A detailed description of the testing methods
are reviewed with the couple as well as the risks which are involved with
each. Upon an understanding of the procedures, the counselor discusses the
many possible outcomes which could be the result of the diagnosis. Finally,
before any tests are performed, anxieties from either of the parents are
addressed as well as the psychological well-being of the parents.
II. Methods of Genetic Testing
Procedures performed today are designed to evaluate the probability that
a fetus will be born with a serious physical or mental handicap as a result
of a genetic abnormality. Some of the disorders which can be identified
are cystic fibrosis, trisomy 21, commonly known as Down syndrome, B-Thalassemia,
neural tube defects, Tay-Sachs disease and many others (Watson, 1992).
A. Amniocentesis
Amniocentisis is the most common prenatal test performed today (Morris,
1993). While the test is not totally risk free, estimated fetal loss due
to amniocentesis is less than 0.5 percent (O'Connor, 1989). This procedure
involves the extraction of a small amount of fluid surrounding the developing
fetus. Within this fluid are cells which contain the genetic information
of the fetus. Upon analysis of this fluid, the determination of the sex
as well as the location of genetic abnormality causing genes can be identified.
While the numbers sound safe and the odds of injury low, amniocentesis has
one major drawback. Due to the nature of the technique, the earliest an
amniocentesis can be performed is in the second trimester of the pregnancy,
approximately the fifteenth week. Once the procedure has been performed,
it takes any where from two to four weeks for the results of the cultured
cells to be announced. Because of these delays, the anxiety of the parents
increase and the options available to the "parents" can become
limited.
While there are several aspects which a couple needs to think about upon
receiving information of the test results, one basic principle surrounds
the entire decision. What will we do with our fetus? One of the most common
options for patients with a geneticly abnormal fetus is the termination
of the pregnancy. This may seem harsh to some, yet realistic for others.
The implications of emotional sensitivity, religious beliefs and moral or
ethical understandings become greatly enhanced with the advancing gestation
period.
B. Chorionic Villi Sampling
The late detection of fetal abnormalities from an amniocentesis test has
led to the chorionic villi sampling (CVS). While the two tests are very
similar, CVS can be performed at a much earlier age of the fetus compared
to an amniocentesis test. This test can be performed as early as eight weeks
into the pregnancy. The results are ready within two to three days, giving
parents a diagnosis of chromosomal abnormalities or genetic diseases within
the first trimester.
Chorionic villi sampling involves the insertion of a plastic catheter through
the cervical canal into the uterus to an area of placental development.
A small sample of placental tissue, chorionic villi, is then removed by
aspiration. Because the cells of the chorionic villi are proliferating rapidly,
enough cells are undergoing mitosis to allow karyotyping. The karyotype
gives a quick and conclusive "map" of the fetuses chromosomes.
From this information, scientists are allowed to determine disorders such
as trisomy 21, where the 13th and 21st chromosome are abnormal.
C. Alpha-fetoprotein Sampling
A third method of prenatal testing is maternal serum alpha-fetoprotein sampling.
Unlike the previous tests, amniocentesis and CVS, alpha-fetoprotein sampling
requires the mother to have a simple blood test, consequently no risk to
the fetus is involved. "The variation of high and low concentrations
of alpha-fetoprotein in the mother's blood may indicate a risk of fetal
genetic abnormalities" (Morris, 1993). While this sounds like a solution
to the previous "risky" procedures, alpha-fetoprotein sampling
results in a significantly high number of false positives, requiring additional
diagnostic tests. Also, this test is limited to diagnosing neural tube defects
and a low percentage of Down Syndrome.
While both amniocentesis, chorionic villi sampling and alpha-fetoprotein
are common and highly advanced methods of detecting genetic diseases and
chromosomal abnormalities; the reality of the upcoming decisions having
to be made by the perspective parents are extremely traumatic. When any
of the preceding tests detects a genetic defect, "it forces parents
to make a difficult choice. Do they raise a child who might have a serious
congenital affliction? Or do they suffer the torment and pain that accompanies
an abortion?" (Elmer-Dewitt, 1992).
A question which often comes up deals with the purpose and intent of the
gained information. If a couple becomes pregnant and then chooses to have
a prenatal test such as an amniocentesis or a chorionic villi sampling,
what are their motives? Were the tests performed in order to prepare the
couple for what is to come, or were they performed in order to prevent the
birth of a genetically defected child?
III.Case Studies
A. Bob and Sue
I recently had a conversation with a woman who shared with me her most faith
trying experience. Bob and Sue (their names have been changed for privacy)
had been married for seven years, they had two girls and were expecting
their third child, a son. In the beginning of the second trimester, Sue
was involved in a severe car accident. While the two girls were placed in
critical care for a short while, Sue and the baby were not as fortunate.
Due to the impact of the accident and extreme trauma, Sue was placed in
ICU for several days. At that point the doctors were praying that Sue would
pull out of the coma but left very little hope for the fetus. Miraculously,
Sue went home almost a month after the accident happened.
Upon receiving a number of tests due to the extreme difficulties following
the accident, Bob and Sue learned that their son had suffered extreme brain
damage. At that point the doctors gave the couple two options. Either they
could abort the fetus, or raise a "vegetable". While the parents
were devout Christians viewing an abortion out of the question, they were
troubled by what they had in front of them. Continuing the pregnancy was
never questioned, however, the uncertainty of the quality of life their
child would have was very disturbing. The idea of a child who would never
be able to hug her or know how much she loved him became almost overwhelming
for Sue. The concept of abortion and the understanding of why so many expecting
mothers undergo the procedure became a very real and valid approach to this
difficult situation.
Sue was a nurse at a local hospital, where she had worked with several mothers
in the same situation as she was finding herself. However, the reality of
what was expected of her never set in until the birth of little Jacob. For
the first year of his life, Jacob was home for a total of seven weeks. His
condition required advanced medical attention which Sue could not give.
Just weeks before several surgeries, one of which was the implanting of
a feeding tube, Sue called her doctor because she had been unable to get
Jacob to keep any food down. What became the most difficult words for Sue
to hear were those from her doctor. Upon asking him what to do, he responded
with the statement "take the bottle away and let him go". While
Bob and Sue immediately found a new doctor, that didn't stop the many questions
they asked. One question which Bob and Sue were often asked was WHY? Why
did you allow a child to come into this world knowing that he would suffer
so much? How could you be so selfish to make him go through all that pain?
Was it right for these parents to bring this child into the world? For this
couple I believe it was. Jacob has become the most precious gift they have
ever received. Does that mean that every couple should make the same choice?
I can not answer that, however it is a decision which every couple needs
to address prior to receiving any testing.
While the previous case study is not a result of a genetic disorder which
could have been detected in the first trimester; it is a case which deals
with the decision of what to do with a severely deformed fetus leading to
extreme difficulties in life. Because this couple had made a decisive stance
prior to the knowledge of their sons condition, questions with the future
were less stressful. Bob and Sue were strictly opposed to abortion, there
was no decision which needed to be made. They would continue with the pregnancy
and wait for the best.
B. Achondroplasia Couple
A second case study, dealing with a couple who both have achondroplasia,
an inherited form of dwarfism, questions the purpose and use of the perspective
test results. In most cases, couples seek out a genetic counselor because
they want to know if they are carrying a "defective" fetus. However,
in this case it is the exact opposite. The couple requested a genetic counseling
center to perform necessary tests to determine if their fetus was "normal"
(Fackelmann, 1994). Upon the analysis of the results, if the child-to-be
would grow to be of 'normal' height, they would abort it and try again for
a "dwarf child".
IV. Effects of Prenatal Testing
A. Termination of Pregnancy
Perhaps the first question which a couple must answer is their stance on
abortion. Obviously, the easiest answer for some who receive information
that they will be parents of a genetically defected child is a termination
of the pregnancy. However, the emotional torment and pain of that decision
leads to many psychological and emotional feelings which can be as overwhelming
as the birth of a genetically defected child. Weighing every decision before
the results of the test are known will give the parents a more conclusive
idea as to what they really believe is best for them.
Does prenatal genetic testing really benefit women? This is a question posed
by many leading professionals and psychologists. Is it really an advantage
to knowing the genetic information of one's fetus compared to the emotional
consequences upon making a decision on what to do with that fetus?
No clear research has yet suggested that testing does in fact benefit women.
The life changing events, social and emotional, which are a direct result
of the testing may be more hazardous than the raising of a handicapped child.
Karen Rothenberg, author of Women and Prenatal Testing, argues that "the
consequences for women are real, and that they need to be taken seriously
if we are to develop humane and rational approaches to genetic testing".
Are the methods which are being used today preparing women for what they
are about to be faced with? Having to make the decision of terminating a
pregnancy leads to many life long consequences. A haunting phrase by a woman
following the abortion of a genetically abnormal fetus reads: "when
termination was completed all became vague" (Clarke, 1994).
There tends to be very little if any social support for the woman and family,
leaving them to handle the loss of the fetus alone. Charles Bosk, author
of All God's Mistakes: Genetic Counseling in a Pediatric Hospital, argues
that "The counselors use.....the goal of patient autonomy as a ground
for patient abandonment." The insistence of counselors to remain 'non-directive',
neutral or no partiality, has lead to a "denial of the emotional needs
of the counsellees" (Bosk, 1992). It is the counselors job to not only
prepare the couple for the screening, but especially in helping the entire
family deal with the traumatic consequences of the diagnosis. If this leads
the couple to terminate the pregnancy, than the counselor needs to help
the family cope with the loss of their fetus.
In the case of the Achondroplasia couple the parents simply state that they
will terminate a "normal" child. Due to responsess such as thie,
some have sought to prevent this type of usage of the tests. However, according
to geneticist Eugente Pergament of Northwestern University Medical School
in Chicago, the counselor and geneticist should not let their personal
feeling interfere with the couple's choice. The dwarf couple may feel it
would be psychologically difficult to raise a normal-size child (Fackelmann,
1994). In this case, the mother feels it would be less painful and traumatic
to raise a dwarf child like herself. Hence, the amount of emotional pain
from the genetic testing would be less than the pain of raising a 'normal'
child. In the end, this couple will probably suffer more psychological and
emotional pain if they have a normal child, as compared to terminating the
pregnancy.
While Pergament believes the decision is solely up to the couple, many other
professionals do not agree. The director of the Center for Biomedical Ethics
at Case Western Reserve University in Cleveland, Thomas Murray states that
an abortion of a healthy fetus because it is healthy is very difficult to
justify morally. While this particular case may seem a bit unique, the reality
of perfectly normal fetuses being aborted daily is not uncommon. In countries
like China, fetuses are being aborted daily in response to their sex. Parents
want to give birth to a male child, if the fetus is female, they abort and
try again. According to genetic counselor Ann Pellegrino, the job of the
center is to provide the couple with the information they request, not to
judge the morality of how the couple will use the information.
B. Continuation of Pregnancy
While many couples find termination of the pregnancy the best route for
their abnormal fetus, still others disagree. In the case of Bob and Sue,
termination of the pregnancy was not an option. While Sue did admit to
having doubts as to the decision of delivering Jacob, she replies that she
would never want it any differently. Jacob is the most precious gift she
has received, which she accredits to God. The psychological effects of
terminating the pregnancy would have been far too much for her to handle.
Clearly this is an indivdual choice, one which needs to be made with an
open mind and good council.
C. Psychological and Emotional Effects
While many view prenatal genetic testing results to contain valuable information,
what is this really telling them? How will one benefit from such information?
Granted, for some the knowledge of such a fetus will provide ample time
for the couple and family to become aware and prepared for the condition.
This will result in better care for the child and hopefully a shorter time
frame needed for all to become accepting of the situation. However, what
about those who are not prepared to make a decision regarding the future
of the fetus? It has been proven that "prenatal genetic testing is
a major psychological and social event for women, regardless of what testing
reveals" (Rothenberg, 1994).
Does it make a difference as to why the testing is being performed? Since
the Roe v. Wade court case allowed pregnancy termination to be legal, why
is the genetic testing of this couple being questioned? Every day in this
country, for whatever reasons, healthy fetuses are being terminated. Is
the morality of using genetic information in order to terminate a healthy
fetus the question here? Or is it the idea that technology is imposing a
genetic disease upon another human being?
V. Conclusions
Regardless of where one stands on the issue of life, the key here is the
emotional and psychological standings of a woman following a prenatal genetic
test, regardless of the results. Once a woman agrees to the testing of her
fetus, the reality of making a potential decision affecting the future of
this fetus is real. The psychological implications of the test have the
possibilities of being even more traumatic than the raising of a handicapped
child.
VI. Works Cited
Bosk, C. (1992). All God's mistakes: Genetic counseling in a pediatric hospital.
Chicago: University
Clarke, A. (1994). Genetic counseling: Practice and principles. London:
Routledge.
Fackelmann, K. (1994). DNA dilemmas: Readers and 'experts' weigh in on biomedical
ethics.
Mennuti, M. T. (1989). Prenatal diagnosis-Advances bring new challenges.
The New England
Spielman, B. (1995). [Review of Women and prenatal testing]. Journal of
Law, Medicine & Ethics,
Rothenberg, K. and Thomson, E. (1994). Women and prenatal testing. Columbus:
Ohio State
Watson, J. D., Gilman, M., Witkowski, J., Zoller, M. (1992). Recombinant
DNA. New York: W.