Applied embryology

Question 1

Definition of teratogen

Answer 1

• Drug or substance that causes a birth defect
• Can be environmental exposure
• Detrimental to development of embryo/ foetus in utero

Question 2

Complications of teratogens on the foetus/ embryo

Answer 2

• Death
• Learning difficulties
• Sensory deficiencies
• Structural problems
• Cancer
• Intrauterine growth restriction/ defect
• Neurodevelopment/ behavioural problems
• Developmental delay

Question 3

Does it matter when teratogenic exposure occurs

Answer 3

• Adverse effect at any stage in utero
• 1st trimester
  
  • Structural defects during organogenesis
  • Greatest risk between weeks 3 and 11
• After week 12 → functional and growth defects

Question 4

Complications of alcohol on foetal growth

Answer 4

• Foetal alcohol syndrome
• Alcohol passes through placenta → baby
• No safe amounts of alcohol

Question 5

Rubella during pregnancy

Answer 5

• Congenital rubella syndrome
• Classic triad
  
  • Sensorineural deafness
  • Eye disease → retinopathy, cataract and microphthalmia
  • Congenital heart disease → pulmonary artery stenosis and PDA

Question 6

Varicella during pregnancy

Answer 6

• Limb hypoplasia
• Skin scarring
• Eye defect
• Greatest risk during trimester 2

Question 7

Complications of late pregnancy

Answer 7

• Higher intake of opiate medications during labour → neonatal respiratory depression
• Growth restriction
• Higher incidence of trisomy 21

Question 8

Cardiac birth defects

Answer 8

• Occurs very early in pregnancy → heart is first functional organ to develop day 2½2
• Causes
  
  • Genetic
  • Drugs
  • Infection

Question 9

Folic acid during pregnancy

Answer 9

• 400 mcg intake whilst conceiving and during pregnancy
• Protection against neural tube defects → spina vivid
• Higher dose (5mg for those higher risk of NTD)