Teratogenecity refers to the production of fetal defects caused by teratogenic agents. Teratogens can halt pregnancy or cause birth defects and include various classes such as radiation, maternal infections, chemicals, and drugs. Specific teratogens discussed include alcohol, illegal drugs, radiation, obesity, infectious diseases, diabetes mellitus, and various teratogenic drugs. The document concludes that teratogenic exposures can result in a wide range of effects from infertility to fetal death and that women can reduce birth defect risks by managing health conditions, adopting healthy behaviors, and consulting healthcare providers before and during pregnancy.

1. Teratogenecity
Saleem Ahmad
Reg. No. 2018508017
II-M.Sc. Biomedical Science

2. Introduction
• Teratogenesis refers to the production of defects in the
fetus. A teratogenic agent is responsible for producing such
a defect. The term teratogen usually is cited in the context
of causing anatomical defects in an embryo that was
previously differentiating normally.
• Teratogens include irradiation, chemicals (drugs), and
infectious agents.

3. Teratogenecity
Teratogenicity is a manifestation of developmental
toxicity, representing a particular case of
embryo/fetotoxicity, by the induction or the increase
of the frequency of structural disorders in the
progeny.

4. Teratogen
 A teratogen is an agent that can disturb the development
of the embryo or fetus. Teratogens halt the pregnancy or
produce a congenital malformation (a birth defect).
 Classes of teratogens include radiation, maternal
infections, chemicals, and drugs.

5. Types of teratogens
Alcohol and illegal drugs
Alcohol is the most common
cause of congenital disorders that
can be prevented.
Alcohol is poisonous to a fetus and can cause brain
damage. Drinking alcohol while pregnant can cause
the fetus to get fetal alcohol syndrome.

6. Illegal drugs, like heroin and
cocaine, are also poisonous
to the fetus and can cause
many different congenital problems. For example,
cocaine use during pregnancy can cause microcephaly (a
smaller head size than usual) and problems with the way the
fetus's urinary system and genitals grow.

7. Radiation
Ionizing radiation can injure the
Developing embryo due to cell
death or chromosome injury.
The most critical exposure period is 8-15 wk after
fertilization.
There is no proof that human congenital malformations
have been caused by diagnostic levels of radiation.

8. Obesity
During pregnancy, obesity is associated
with adverse outcomes that include macrosomia,
hypertension, pre-eclampsia, gestational diabetes mellitus
(GDM), and fetal death.
Obesity occurs a number of metabolic abnormalities, including
abnormal glucose metabolism, is associated with a higher risk
of malformations.

9. Infectious Agents
The lethal or developmental effects of infectious agents are the result of
mitotic inhibition, direct cytotoxic effects, or a vascular disruptive
event on the embryo or fetus.
Infections that do not result in congenital malformations but do cause
fetal or neonatal death.
Maternal infections caused by most organisms which can cross the
placenta (including rubella, mumps, smallpox, syphilis, and malaria)
may result in abortion or stillbirth.

10. Diabetes mellitus
Hyperglycemia leads to inhibition of the myoinositol uptake
that is essential for embryonic development during
gastrulation and neurulation stages of embryogenesis.
Rare malformations include situs inversus and caudal dysplasia,
vertebral and renal anomalies, imperforate anus, radius
aplasia, renal abnormalities including agenesis and dysplasia,
and other defects.

11. Teratogenic drugs
According to Food and
Drug Administration
(FDA),Approximately 3-5% of live births are complicated
by a birth defect each year totaling around 120,000
babies.
Additionally, more women taking any kind of medication
has more than doubled in the last 30 years.

12. Drugs that are capable of acting
as teratogens include

14. Commit to Healthy Choices to Help
Prevent Birth Defects
We know that not all birth defects can be prevented. But, we also
know that women can increase their chances of having a healthy
baby by managing health conditions and adopting healthy
behaviors before becoming pregnant. Make a PACT, a commitment
to yourself, to get healthy before and during pregnancy by actively
trying to plan ahead, avoid harmful substances, choose a healthy
lifestyle, and talk with your healthcare provider.

15. 1. Plan ahead
Get 400 micrograms (mcg) of folic acid every day.
See a healthcare professional regularly.
2. Avoid harmful substances
Avoid alcohol at any time during pregnancy.
Avoid smoking cigarettes.
3. Choose a healthy lifestyle
Keep diabetes under control.
Maintain a healthy weight.
4. Talk with your healthcare provider
Talk to a healthcare provider about taking any medications.
Talk to a healthcare provider about vaccinations (shots).

16. Conclusion
• Teratogenic exposures result in a wide variety of effects that
range from infertility, prenatal onset growth restriction,
structural defects, and functional CNS abnormalities to
miscarriage or fetal death.
• A teratogen is defined as any environmental factor that can
produce a permanent abnormality in structure or function,
restriction of growth, or death of the embryo or fetus.

17. References:
• https://www.glowm.com/section_view/heading/Tera
tology%20and%20Drugs%20in%20Pregnancy/item/9
6
• https://www.medicinenet.com/script/main/art.asp?
articlekey=9334
• https://emedicine.medscape.com/article/260725-
overview
• https://www.cdc.gov/ncbddd/birthdefects/preventio
n.html