Teratology

Question 1

Principles of teratology

Answer 1

• Critical period: first trimester exposure to teratogens, important for some agents and less so for others
• Each age produces specific pattern of abnormalities, usually minor malformation and not a single major specific malformation
• Teratogens are species specific
• The abnormalities are dose-response and bioavailability dependent
• Some degree of genetic predisposition occurs
• Time frame for malformations vary based on organ system involved (usually 3-8 wks but some systems are later)

Question 2

Meanings and limitations of FDA drug use categories

Answer 2

• FDA categories/list is sparse and inaccurate, only 40% of drugs have a pregnancy category and 60% of these drugs are cat C (not tested in humans)
• A= safe to use during pregnancy
• B= animal studies ok and not enough human studies or human studies ok and animal studies unsafe
• C= animal studies unsafe and no human studies or no studies in either
• D= human studies show risk but must be balanced against benefit
• X= studies in animals or humans show fetal abnormalities, contraindicated during pregnancy

Question 3

Types of birth defects related to fetal etoh exposure

Answer 3

• Etoh exposure is most common cause of preventable intellectual disability in US (low IQs)
• Causes 1/6th of cerebral palsy cases, also causes growth def, irritability, microcephaly, long and smooth philtrum and thin upper lip, cleft palate/lip, congenital hip dislocation, tapering distal phalanges w/ underdeveloped fingernails, heart and kidney malformations