Teratogens

Question 1

What is a teratogen?

Answer 1

Any substance that interferes with normal development.

Question 2

What are the possible results of a teratogen?

Answer 2

Death, growth retardation, malformation or functional deficit

Question 3

What are the categories of teratogens?

Answer 3

Infectious Agents, Physical Agents, Chemical agents, and maternal metabolic/genetic factors.

Question 4

What are some of the characteristics of a teratogen?

Answer 4

Increased occurence of phenotypic effect with exposure, Supportive animal model, Dose-Response relationship, and Biologic Plausibility.

Question 5

What are the factors affecting the potency of a teratogen?

Answer 5

Dose, route of administration, duration, timing, and host susceptibility.

Question 6

What are the critical periods in human development?

Answer 6

0-15 days is the ‘All or nothing’ period. The embryo is not susceptible to teratogens.
3-8 weeks is when the baby is vulnerable; Organogenesis. Disruptions will have great effect.
Once organs are formed, exposures will not cause a structural defect.

Question 7

When does the neural tube form?Heart?

Answer 7

Neural tube forms at 3-4 weeks; Heart formed by 8 weeks.

Question 8

What is the risk of exposure later on in pregnancy?

Answer 8

Exposures can cause growth retardation or functional disorders; Stillbirth, growth retardation, impaired IQ, and behavioral problems

Question 9

Discuss the effects of multiple exposures

Answer 9

Exposures can be additive, antagonistic or syngerized.

Question 10

Discuss Thalidomide

Answer 10

A sedative used to treat pregnancy related nausea; Caused severe limb reduction defects.

Question 11

Discuss Diethylsilbesterol

Answer 11

Medication given to prevent pregnancy complications; Caused anomalies of the reproductive tract and increased vaginal cancer risk

Question 12

Discuss Hydantoin

Answer 12

Causes Dymorphic faces, microcephaly and congenital heart defects

Question 13

Describe the effects of anticonvulsant medications

Answer 13

Dysmorphology, developmental delay, NTDs; Folic acid recommended

Question 14

Describe the effects of psychiatric medications

Answer 14

Not strongly teratogenic

Question 15

Describe the effects of mood stabilizers.

Answer 15

Increased risk of heart defects including Ebstein’s anomaly; Displaced tricuspid valve allows blood back into right atrium.

Question 16

Discuss Alcohol as a teratogen.

Answer 16

Can cause growth restriction, Narrow palpebral fissures, thin upper lip and CNS abnormalities

Question 17

Discuss Cocaine as a teratogen.

Answer 17

Readily crosses the placenta and concentrates in amniotic fluid; Preterm delivery, Placental abruption

Question 18

Discuss cigarette smoking as a teratogen.

Answer 18

Increased miscarriage risk, abnormal placentation and reduced fetal growth.

Question 19

Discuss the effects of Cytomegalovirus

Answer 19

Hydrocephalus, eye issues, hearing loss.

Question 20

Discuss congenital rubella

Answer 20

Cataracts, Deafness; All organs can be affected

Question 21

Discuss diabetes mellitus

Answer 21

Increased risk of NTDs, heart and skeletal defects, and Macrosomia

Question 22

Discuss the risk of maternal hyperthermia

Answer 22

Increased risk of NTDs when exposed in first 4 weeks.