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In 1865, an Austrian monk, Gregor Mendel, studied the common pea
plant. It was the beginning of the end to speculation on heredity
and its effects.
Slowly, scientists learned that the genetic principles
that applied to Mendel's peas also applied to humans. Even 100 years
ago, people
realized some diseases ran in families - men with hemophilia tended
to have male relatives on their mother's side of the family with the
same disease. Despite the understanding that some diseases ran in
families, how the disease was transmitted from healthy parents to
their children remained a mystery.
Almost 80 years later, the expression "genetic
counseling" was
coined and the modern concept of genetics was born. In the 1940s and
1950s, doctors and scientists began using genetic information to help
families understand the role heredity plays in inherited diseases
and birth defects. Genetic testing entered modern times in 1967 when
amniocentesis was introduced to identify possible chromosomal and
genetic abnormalities in the fetus.
Today, University of Iowa Health
Care offers comprehensive genetic screening, testing and counseling
to pregnant women and pre-conception
counseling for couples who know of existing genetic abnormalities
in their families.
Roger Williamson, M.D., obstetrics and gynecological
staff physician at University of Iowa Hospitals and Clinics said screening
and/or
testing can be done at various stages of pregnancy.
The risk of having
a child with a chromosome abnormality increases with the age of the
mother. Traditionally, women age 35 years of age
and older at delivery have been offered testing. If a couple wants
testing under these circumstances, the options include a test performed
between 10 to 12 weeks, called chorionic villus sampling (cvs) or
an amniocentesis which is usually performed at 15 to 16 weeks.
Other
women may opt for screening, and if this indicates a potential problem,
definitive testing as indicated above can be scheduled. An
ultrasound examination of the fetus may also be part of the screening
process. .
The quadruple marker screen, available through the Iowa
State Health Department to all pregnant women in Iowa, is conducted
between 15
to 20 weeks of pregnancy. This screen can indicate an increased risk
for a fetal chromosome abnormality as well as a certain types of defects
such as spina bifida (opening in the spine).
Testing is becoming available which will allow screening earlier
in the pregnancy, between
11 to 14 weeks. The earlier testing can be combined with
the quadruple marker screen. This combined testing will decrease the
number of women who are "screen
positive" or
whose risk is increased.
Equally important is the counseling aspect
of prenatal testing. If an abnormality is found, the information must
be as complete as possible.
If a pregnancy continues, this gives those who will care for the baby
the opportunity to provide extensive counseling before delivery. "This
results in a couple who is far better prepared for the intensive care
services that may be required," Williamson said.
"Counseling helps inform couples of the testing options available.
Counseling also gives couples the opportunity to learn the latest
information about conditions that may affect a fetus or child based
on family history and other factors," he said.
If you have a
health-related question, or to make an appointment, call UI Health
Access - 800- 777-8442 or 384-8442.
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