Teratogen:
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Any environmental agent that has an
adverse influence on fetal development
May be substances that are added to the fetal
environment
May also be substances that are deficient to
the fetal environment
Types of Teratogens
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Prescription Drugs
Industrial Chemicals
Social/Illegal Drugs
Disease
Radiation/Chemical Warfare
Maternal Influences
Determining the extent of
damage to the fetus depends
on…….
1. TIME and DURATION of exposure
Exposure during the period of
organogenesis (when major organs begin to
form) will result in major impairments and
malformations
 Exposure during the fetal period results in
growth impairments and delay
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Determining the extent of damage to
the fetus depends on…….
2. Genetic Susceptibility The genotype of mother and genotype of fetus play
an important role.
Example: The way the mother metabolizes a certain drug will
determine what and how much the fetus will be exposed to.
Metabolism (from Greek: μεταβολή "metabolē", "change" or Greek:
μεταβολισμός metabolismos, "outthrow") is the set of chemical
reactions that happen in living organisms to sustain life. These
processes allow organisms to grow and reproduce, maintain their
structures, and respond to their environments.
THINK, PAIR, SHARE
1. Think of some examples of TIME (how many
weeks gestation) and DURATION (how long
was the mother exposed to the toxins)
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What kinds of toxins could someone be
exposed to over a long period of time?
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What kinds of toxins might need only a
little bit of time to cause damage?
Teratogen Chart
Thalidomide
(prescription drug)
Was a prescription drug sold mainly
during the late 1950’s early 1960’s,
used to alleviate morning sickness.
Critical period for exposure is during
organogenesis
Specificity of malformations is linked
to time of exposure:
35-37 days- no ears
39-41 days- no arms
41-43 days- no uterus
45-47 days- no tibia
47-49 days triphalangeal thumbs
Industrial Chemicals
Cleansers, varnishes, lacquers, resins, leads, pesticides,
herbicides (agent orange) and mercury (Minimata Disease)
Illegal Drugs, Alcohol and
Tobacco
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Low birth weight
Born addicted to drugs
Withdrawal symptoms
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Fetal Alcohol syndrome
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Behavioral
problems/impulse
control
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Radiation/Chemical Warfare
Maternal Disease
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Rubella
Herpes simplex,
AIDS
Chickenpox
If the mother has these diseasescan cause serious
malformations, mental
retardation and miscarriage or
Infant mortality.
Other Maternal Influences
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Malnutrition (lack of necessary
vitamins, minerals and proteins)
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Stress/Anxiety
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Altered Metabolism (Diabetes mellitus)
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Fetal Origins Hypothesis
Fetal Origins Hypothesis
“the environment experienced
during the individual’s prenatal
life ‘programs’ the functional
capacity of the individual’s
organs, and has subsequent
effect on the individual’s
health” (Slater& Lewis, 2007)
Fetal Origins Hypothesis
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Fetus develops a predictive adaptive
response to the prenatal environment
Fetus develops according to its current
environment
When environment is lacking the fetus goes
into survival mode and resources are
redistributed
ACTIVITY
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Go to www.otispregnancy.org
Click on “FACTSHEETS” in the right toolbar
Choose 1 factsheet to research
Make an informative flyer including:
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Definition
Common reason a woman would ingest/be around this
substance
In your own words: Can this substance cause birth
defects?
Conclusion: What would you suggest if someone asked
you if it was ok to take that substance?
References
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http://a.abcnews.com/Health/popup?id=4610286&contentIndex=1&page=2
&start=false
http://www.kianh.org.uk/agentorange.htm
http://hidhist.wordpress.com/category/gulf-war-syndrome/
http://www.who.int/violence_injury_prevention/violence/world_report/fact
sheets/ft_child.pdf
http://www.who.int/ceh/risks/en/
http://carolguze.com/text/442-13-teratogens.shtml
http://www.pixelpress.org/chernobyl/index.html
http://books.elsevier.com/companions/0240804155/crack/crack1.htm
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http://www.whale.to/a/gulf32.html
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http://embryology.med.unsw.edu.au/Defect/rubella.htm (awesome
website!!)
Slater, A. & Lewis, M. (2007). Introduction to infant development. New
York: Oxford University Press.
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