Birth defects

Question 1

Frequency of birth defects

Answer 1

3% in newborns, 3% within 2 years

Question 2

5 types of defects

Answer 2

1. chromosomal
2. Mutations
3. Enviromental
4. Multifactorial - epigenetic
5. Unknown

Question 3

Types of chromosomal abnormalities

Answer 3

1. Aneuploidy - non-46
2. Polyploidy - multiples of 23
3. Structural abnormalities

Question 4

Frequency of chromo.

Answer 4

1:160
20% recognized preg. end in miscarriage
60% of miscar. are abnormal

Question 5

Freq. of environmental defects

Answer 5

7%

Question 6

3 types of env defects

Answer 6

1. physical and chemical - x-rays, drugs, etc
2. mechanical - amniotic bands
3. maternal - nutrition etc.

Question 7

6 principles of teratology

Answer 7

1. Susceptibility depends on genotype (of conceptus) and env
2. Susceptibility depends on stage of exposure - critical
3. Access to fetus depends on nature of the influence
4. Agents act in specific way
5. There are 4 manifestations of deviant dev (death, malformation, retardation, funct. def.)
6. Dose response