Little Is Understood About Alcohol's Effect on Fetal Development,
ScienceDaily (June 17, 2010) — It's long been known that alcohol use
in pregnancy can lead to children with mental retardation and birth
defects, but researchers who study fetal alcohol syndrome (FAS) have
not made definitive progress on preventing the disorder, detecting
it early, or effectively treating it, say researchers from
Georgetown University Medical Center.
In the issue of Developmental Neuroscience, four first-year medical
students at Georgetown University School of Medicine looked into the
science and clinical treatment of FAS, and found that although there
is much ongoing study, no new medical strategies exist to change the
grim outcome that can occur when a fetus is exposed to alcohol.
"Although there is a lot of research in the field to determine how
alcohol acts on the developing brain, there is not much translation
into the clinic," says Sahar Ismail, now a second year medical
student. "What surprised us the most was the lack of sensitive and
specific diagnostic tools to identify children with FAS, given its
prevalence and harmful effects on the child, family, and society."
Working with her on the study were medical students Stephanie
Buckley, Ross Budacki, and Ahmad Jabbar -- each student contributed
equally. Their study was a project for the Sexual Development and
Reproduction Module under directorship of G. Ian Gallicano, PhD, an
associate professor in the Department of Biochemistry and Molecular
& Cellular Biology.
"This is a very important review, because it combed the research
literature on FAS, and concluded that nothing has changed
clinically," Gallicano says. "Not every woman who drinks alcohol
will have a child with FAS, but because so much remains unknown,
women are still advised not to drink any time during pregnancy."
Even the question of whether alcohol is a teratogen (a chemical that
causes nervous system abnormalities) in the first days or weeks of
pregnancy -- when a woman may not know she is pregnant -- has not
been answered fully, says Ismail. Mouse studies show alcohol can
have detrimental effects at any stage of fetal development, but
"only so much can be concluded about humans from mouse studies," she
says. "All we can say now is that there is no safe period to drink."
What is clear, however, is that alcohol is the leading cause of
preventable mental retardation, the researchers say. FAS is
relatively uncommon, affecting .2 to 1.5 live births in every 1,000,
but fetal alcohol spectrum disorders (FASD), the less severe form of
FAS, is much more common and has a broad range of the same symptoms,
they say. "Taken together, both FAS and FASD, are more common than
the public realizes but are entirely preventable," Ismail says.
The study authors say FAS research shows:
Alcohol can have a range of effects on the baby but the fetal brain
is particularly at risk because of its complex blood networks.
Alcohol is carried from the mother to the child through blood that
flows through the umbilical cord.
Many factors influence the severity of alcohol's effects, such as
maternal genetics, increased maternal age, history of alcohol abuse,
poor prenatal care. In the genetics realm, for example, researchers
have found that women with a more efficient enzyme that breaks down
alcohol have a decreased risk of giving birth to a child with FAS.
Alcohol can cause dramatic and irreversible effects on the fetus,
such as developmental delay, head and facial irregularities,
seizures, hyperactivity, attention deficits, cognitive deficits,
learning and memory impairments, poor psychosocial functioning,
facial irregularities, and motor coordination deficits. However, the
exact developmental phases in which alcohol has these specific
effects on the fetus are not entirely known
Based on animal studies, consumption of alcohol during the times in
animals that correspond to the first 2-3 weeks in human brain growth
are detrimental to the brain. But much remains unknown about
alcohol's vast mechanism in growth development in humans, most
importantly on neurogenesis.
It is very important to identify FAS early in life in order to
provide the child with the appropriate counseling and guidance as
early as possible. But, at this point, there is no treatment or
specific and sensitive diagnostic tools to diagnose FAS early in
pregnancy or early after birth. Still, the authors say there is
ongoing research aimed at devising better diagnostic tools for FAS.
These include a panel of genes that are altered in a developing
fetus and a kit to examine a newborn's stool for telltale chemicals.
Research is underway to find biomarkers that can inform physicians
if a pregnant woman is using, or chronically abusing, alcohol. One
marker, for example, can be detected in a woman's bloodstream for at
least 28 days after alcohol use. Other researchers are studying
biomarkers in amniotic fluid that can distinguish between high-risk
and low-risk pregnancies. Still, the authors say there is
comparatively little investigation on these ideas.
Prevention of FAS is an important goal primarily because so little
is understood about the adverse effects that alcohol has on the
developing fetus. Current prevention programs focus on educating
potential mothers at risk for conceiving a child with FAS. However,
potentially powerful approaches are being studied in animals, such
as the use of agents to protect the developing brain early in
pregnancy or to treat brain malformations caused by alcohol
exposure. Although there is vast research in this area, clinical
strategies to reverse the effects of alcohol are not foreseeable in
the near future, the authors say.
Sahar Ismail, Stephanie Buckley, Ross Budacki, Ahmad Jabbar, G. Ian
Screening, Diagnosing and Prevention of Fetal Alcohol
Syndrome: Is This Syndrome Treatable?
2010; 32: 91-100 DOI: 10.1159/000313339
Georgetown University Medical Center (2010, June 17).
understood about alcohol's effect on fetal development, researchers
July 7, 2010