Prenatal Development, Birth and The Newborn

1. Prenatal Development, Birth and The Newborn Behavioral ScienceTues, Jan 26 2006

2. Prenatal Development • Overview • 3 Stages • Major achievements of each stage • Prenatal Developments • Basic Concepts • Critical periods • Teratogens

3. 3 Stages of Prenatal Development • Germinal Stage • Embryonic Stage • Fetal Stage

4. Germinal Stage • Start – conception • End – attachment to uterine wall • Major achievements Rapid cell division Attachment to uterine wall

5. Embryo Stage • 2nd to 8th week • Start – attachment to uterine wall • End – formation of bone cells • Major achievements • Growth (from ¼ inch to 1 inch) • Major organs formed (~6.5 weeks) • Movement

6. Critical Periods • The developing child is most susceptible to teratogens during the embryonic stage • This is when most of the major organ systems form and begin to function • Each organ has a specific critical period • And is influenced by different teratogens: • E.g., Alcohol (FAS), Radiation, Tobacco, Maternal Disease

8. Fetal Stage • 8th week to ~38 weeks • Start – formation of real bones • End – birth • Major achievements • Growth (3 in. -> 20 in.) • Movement felt by mother • Hearing (~5months) • Sensitive to light

9. Ovum The ovum is embedded in follicle cells

10. 17th century drawing of Human sperm By Hartsoeker The miniature human was thought to grow once it entered the ovum

11. Sperm in the presence of an ovum

12. Ovum Sperm

13. The Germinal Stage

14. Overview of Germinal Stage

15. The Embryonic Stage

16. Implantation in uterine wall The start of the embyronic stage

17. Neural Tube (26 days) Head 3 mm 0.12 in. Heart Starts beating ~18 days

18. Chorion – develops into placenta

19. ~ 3.5 weeks Head Heart

20. Face at ~4.5 weeks Eye Nostrils Mouth

21. 6 weeks Eye Arm Leg

22. 5 – 6 Weeks 1.5 cm 0.6 in Primitive human form

23. Eye at 6 ½ weeks Eyes close ~ 9 weeks Open again at 7 months

24. 7th week

25. The Fetal Stage

26. Beginning of the Fetal Stage Formation of bone cells

27. Fetal Movement

28. Fetal thumb sucking

29. 4 1/2 months 25 cm 10 in.

30. 5 ½ months 30 cm 12 in Layer of fat protects the skin (vernix)

31. Hand 5 weeks - bud 3 months - fingers 17 weeks – fingernails

32. Fetus and placenta

33. 5 months 25 cm 10 in.

34. 7 months • Growth slows – • If same growth rate continued the child would weigh ~200 lbs at birth • 16 inches / 3 lbs • Viable – able to survive outside the womb • Age of viability now between 22-26 weeks • Digestive / Respiratory systems working • Babies born as little 1.5 lbs have been able to survive

35. Brain Development • Occurs throughout prenatal period and after birth • 3 major aspects • Cell proliferation • Development of new neurons • Cell migration • Neurons move to “proper” location • Cell differentiation • Neurons specialize

36. Birth Average Length = 20 inches Average weight = 7 lbs

37. Right after birth A few hours later

38. Effects of Alcohol • Fetal Alcohol Syndrome • High levels of prenatal exposure influence physical structure • Lower levels of prenatal exposure influence neurochemistry • Long lasting effects • See Hunt et al., 1995

39. Low Birthweight

40. Cost of Low Birth Weight

43. The Newborn • Assessment of Newborn Functioning • Apgar Assessment • Brazelton Neonatal Behavioral Assessment • BNBAS • Reflexes

44. APGAR • Developed by Virginia Apgar (1950s) • At birth – mother was the focus of attention • Needed some sort of quick assessment of the infant • Used right after birth • Does not require much training

45. APGAR • 5 Scales (all scored 0, 1, 2) • Appearance • Heart Rate • Response to Stimulation • Muscle Tone • Respiration

46. APGAR • Appearance (color of skin) • 0 = gray / blue skin color • Indicates lack of oxygen • 1 = pink body / gray or blue hands • Indicates lack of oxygen in extremities • 2 = pink tone over entire body

47. APGAR • Heart Rate • 0 = no heart beat seen, heard, or felt • 1 = less than 100 beats per minute • 2 = 100 – 140 beats per minute • Response to Stimulation • Response to birth • Response to suctioning of mouth / nose • 0 = no response • 1 = moderate of low response • 2 = facial grimace / coughing / wheezing

48. APGAR • Muscle Tone • 0 = completely limp • 1 = moderate muscle tone / limbs moderately flexed • 2 = good muscle tone / limbs flexed & active • Respiration • 0 = no breathing within 60 seconds • 1 = irregular or slow breathing • 2 = good breathing / strong cry

49. APGAR • Administered twice • At 1 or 2 minutes and • And again at 5 minutes • Scores greater than 7 at 5 minutes indicate the infant is ok • Likely no intervention is necessary • Scores less than 4 indicate infant is in trouble • Requires immediate attention

50. APGAR • Scores on Apgar are strongly related to infant mortality • Lower Apgar scores are related to a greater chance of the infant dying within the first year of life • Mortality rates in US have dropped • But rank far behind other countries • 1997 - US Ranked # 27 in world • Recent data suggests US has dropped farther