Prenatal Development

Question 1

Describe the various phases of prenatal development
- List major milestones for each phase

Answer 1

1. Germinal period
   - Implantation
2. Period of the embryo
   - Basic structure of organism is formed
3. Period of the fetus
   - Age of viability: Between 22 and 28 weeks

Question 2

Contrast the APGAR assessment with the Neonatal Behavioral
Assessment Scale
- What they are good for? When are they administered?

Answer 2

APGAR (max. 10 points)
- Checks whether child needs immediate medical assistance
- 5 criteria (heart rate, respiration, muscle tone, colour, reflexes)
- Right after birth
- Scale: 0-2
NBAS
- Assesses strength of inborn reflexes and changes in infant’s state
1. Regulating of autonomic reactions
- breathing, temperature, sleep
2. Control of motor system
- quality of baby’s tone, activity level, reflexes

Question 3

Discuss the role of low-birth weight as a risk factor for future development

Answer 3

1. Preterm infants: Born more than three weeks before due date
2. small for-date babies: Did not grow normally, are underweight even when born close to due date

• Most important single risk factor
• Does NOT determine children’s development

1. Major Problems: Brain damage, mental retardation, impaired vision and hearing
2. Minor Problems: Lower cognitive performance, behavioral problems, attention deficit

Question 4

Describe general principles of effects of teratogens on prenatal
development

Answer 4

Teratogen = factor that causes malformation of embryo or fetus

1. Not all embryos or fetuses are equally affected by teratogens
   - The same defect can be caused by different teratogens
   – Principle of equifinality
2. A variety of defects can result from a single teratogen
   – Principle of multifinality
3. The longer the exposure and the higher the dose, the more likely is serious harm
   – Dose-response principle
4. Effects are worst during the period when organ system is forming and growing most rapidly
   – Sensitive period