Prenatal Diagnostic Tests & Teratogens

Question 1

teratogen

Answer 1

environmental agent that interferes with natural growth of infant

Question 2

factors influencing effect of teratogen on fetus (3)

Answer 2

• baby’s gestational age
• amount of teratogen
• susceptibility (i.e. metabolism of mother)

Question 3

common teratogens (7)

Answer 3

• nicotine
• alcohol
• x-rays
• toxoplasmosis (parasite)
• malnutrition
• stress
• advanced maternal age

Question 4

teratogens causing miscarriage/pre-term birth (3)

Answer 4

• nicotine
• advanced maternal age
• stress

Question 5

teratogens have worst effect when

Answer 5

fetus’ organs are developing (weeks 3 -22), except the brain which is always susceptible to damage

Question 6

teratogens causing organ damage (2)

Answer 6

• toxoplasmosis (eye and brain damage)

- malnutrition (nervous system damage)

Question 7

teratogens causing cognitive issues (2)

Answer 7

• alcohol

- nicotene

Question 8

teratogens causing respiratory issues

Answer 8

• malnutrition

- stress

Question 9

ultrasound overview

Answer 9

• high frequency sound waves transmitted onto mother’s abdomen –> resulting echo creates image of developing fetus
• shows baby’s position, gender, gestational age, some brain defects

Question 10

ultrasound pros and cons

Answer 10

• pros: non-invasive + generally safe

- cons: more than 5/pregnancy is not recommended (associated with low-birth wt)

Question 11

amniocentesis overview

Answer 11

• amniotic fluid sample removed via needle/syringe
• fluid tested for chromosomal/genetic abnormalities
• typically done at 15 - 20 weeks

Question 12

amniocentesis pros and cons

Answer 12

• pros: tests for genetic abnormalities

- cons: more invasive than ultrasound, risk of miscarriage (1 in 300 pregnancies)

Question 13

chorionic villus sampling (CVS)

Answer 13

• tube inserted to remove tissue from end of hairlike projections on membrane of developing child
• tissue tested for genetic abnormalities
• typically done at 10 - 12 weeks

Question 14

CVS pros and cons

Answer 14

• pros: tests for genetic abnormalities

- cons: most invasive test, highest risk of miscarriage, risk of limb deformity