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Fostering Healthy Prenatal Development

Fostering Healthy Prenatal Development. Outline. Preconception Stages of development from conception to birth What can interfere with healthy development Teratogens Alcohol Low Birth weight Prevention Cool Tool: http://www.zerotothree.org/baby-brain-map.html. Continued. Proliferation.

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Fostering Healthy Prenatal Development

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  1. Fostering Healthy Prenatal Development

  2. Outline • Preconception • Stages of development from conception to birth • What can interfere with healthy development • Teratogens • Alcohol • Low Birth weight • Prevention • Cool Tool: http://www.zerotothree.org/baby-brain-map.html

  3. Continued Proliferation Migration Differentiation Differentiation wk 0 - 7 wk 8 - 15 wk 16 - 25 wk 26 - 39 Timelines of Human Prenatal Development Tri- mester 1st trimester 3rd trimester 2nd trimester Prenatal week Brain Growth Spurt (Dobbing) --> 2 yrs 1 3 5 7 9 13 15 11 17 19 21 23 25 27 29 31 33 35 39 37 birth Video 1 Neural Induction 5 Specialization 2 Proliferation Cowan Brain Dvlp 7 Cell Death 4 Aggregation 6 Connections 8 Elimination of Connections 3 Migration stages 5, 6, 7, 8 continue postnatally FETUS Ovum Embryo Fetus EMBRYO to birth wks 3 - 7 OVUM birth viability "quickening" Tri- mester 3rd trimester 1st trimester 2nd trimester wks 27 - 39 wks 1 - 13 wks 14 - 26

  4. Stages of prenatal development • 1st trimester : Organ development; Nervous system • Cells multiply • Cells specialize and migrate to where they should be to be part of certain organs • 2nd trimester • Nerve cells proliferate and form connections • External organs continue to be laid down • 3rd trimester • Brain growth spurt • Can hear sounds • Getting ready to come out: lungs very immature

  5. Cowan's Eight Stages in Brain Development 1. Neural Induction (~ days 16-23) 2. Cell proliferation Begins once neural tube has closed off. • Migration 4. Aggregation

  6. Cowan's Eight Stages in Brain Development (cont.) • 5. Specialization of immature neurons (16-25 wks) • a. elaboration of processes • b. adoption of mode of transmission • 6. Formation of Connections • 7. Selective Cell Death • 8. Selective Elimination of Connections

  7. 1-2 3 4 5 6 7 8 12 16 38 20-36 • =Most Common Site of Birth Defect • =Most Common Site of Birth Defect Fig.5 FETUS(wks) EMBRYO (wks) OVUM Central Nervous System Heart Arms Eyes Legs Teeth Palate External genitalia Ears

  8. What can interfere with healthy development • Teratogens: literally means “creates monsters” • Now used to mean anything that mother exposed to that interferes with prenatal development in ways that cause: • Birth defects (visible at birth) • Behavioral Difficulties (behavioral teratogens) • Low birth weight • Prematurity • Low weight for gestational age

  9. 1. Teratogens • How effect fetus/embryo • directly as in radiation • Cross from mother’s body through placenta • Alcohol, infections • Affect gene’s environment • Examples • Thalidomide (drug) • Infections -- Rubella (measles) • Radiation • Alcohol

  10. Thalidomide WarningLabel

  11. Thalidomide Deformities Normal development Hands Feet Effects of time of exposure (3.5 - 7 wks gestational age) on limb deformities

  12. Thalidomide Deformities

  13. Effects of teratogens • Critical periods of exposure • Embryo or fetus vulnerable to specific problems during specific times when undergoing a particular developmental process. (e.g., female fetus may have genital malformations if exposed to androgens <male sex hormone> during 10th week of gestation). • 1st trimester (especially 1st two months): organs, limbs, shape) • 2nd & 3rd trimester: brain size (less visible effects); size of fetus • Vulnerability of fetus (some tougher than others) • General health of mother

  14. 1-2 3 4 5 6 7 8 12 16 38 20-36 • =Most Common Site of Birth Defect • =Most Common Site of Birth Defect Fig.5 FETUS(wks) EMBRYO (wks) OVUM Central Nervous System Heart Arms Eyes Legs Teeth Palate External genitalia Ears

  15. 15 16 17 18 19 20 21 3rd Week of Development Neural Induction embryonic mesoderm neural groove neural fold neural plate brain primitive knot first missed menstrual period neural groove primitive streak somite somite notochord 2-3 mm trilaminar embryo heart tubes thyroid developing prim.streak

  16. 22 23 24 25 26 27 28 otic depression ant. arm bud heart begins to beat heart bulge 4 pairs branchial arches arm & leg buds neuropores neural folds fusing 3 prs branch. arches 2 prs branch. arches post. CR 4 - 5 mm 4th Week of Development Proliferation & Migration

  17. 22 23 24 25 26 27 28 otic depression ant. arm bud heart begins to beat heart bulge 4 pairs branchial arches arm & leg buds neuropores neural folds fusing 3 prs branch. arches 2 prs branch. arches post. CR 4 - 5 mm 4th Week of Development Proliferation & Migration • hydrocephaly • anencephaly • hydroanencephaly • spina bifida

  18. Neural Tube Defects Spina Bifida Day 22

  19. Radiation: Interferes with cell migration and aggregation -- stop too soon

  20. Days Later 16-17 DAY 13-14 DAY Mature nice, neat, cortical layers Rat Brain: Normal Development Proliferation -- Migration -- Aggregation

  21. Days Later Hours afterIrradiation 13-14 DAY Mature subcortical ectopia Radiation on Days 13-14 Proliferation -- Migration -- Aggregation

  22. Hours afterIrradiation Days Later 16-17 DAY Mature scrambled cortex Radiation on Days 16-17 Proliferation -- Migration -- Aggregation

  23. Alcohol: Interferes with migration.Cell don’t stop

  24. Alcohol as a Teratogen • Negative effects throughout gestation • Neurological Damage • Retarded Physical Growth • Face and organ malformations • Unknown what’s a safe dose • Leading known environmental cause of mental retardation • 5-10% of women of child-bearing age have alcohol problem

  25. Alcohol-related birth defects • Facial features: underdeveloped midface Kathy Sulik

  26. Alcohol-related birth defects • Underdeveloped brain

  27. Fetal Alcohol Syndrome (12,000 a year in U.S.) • Mild retardation -- IQ 65-80 • Difficulty with reasoning and planning • Distractable • Don’t learn from mistakes • Indiscriminate affection • Verbal > Reasoning (Anne Streissguth, U of Washington c.1970)

  28. Fetal Alcohol Spectrum Disorder (36,000 a year in U.S.) • More common but less severe form of the syndrome • Effects evident in behavior only • Problems with attention • Inhibition difficulties (start can’t stop)

  29. FAS 8:43

  30. Learning about the effects of alcohol • Correlational studies in humans • Correlations show whether two things tend to be found together • Don’t prove cause • Experimental studies with animals

  31. Correlational studies in humans: Limitations • Difficult to accurately estimate level of alcohol exposure. • Amount mother ingests - Amount fetus/embryo exposed to • Can’t rule out alternative causes of problems child might be showing: Correlated risks • Difficult to study effects of exposure during specific periods

  32. Experimental studies with animals • Advantages: • Control when and how much exposed. • Compare to control group similar except for exposure to alcohol • Infer that alcohol causes differences in offspring. • Look in a fine grained way at how alcohol exposure disrupts brain development. • Disadvantages: • Unclear how findings apply to humans especially for things that only humans do.

  33. Findings from animal studies • Ist trimester: • Facial malformations, worse for growth and behavior than later exposure. • Effects on behavior even in the absence of obvious physical defects. • Effects to nervous system due to exposure in only 2nd and 3rd trimester.

  34. 2nd semester • When nerve cells are generated and go to appropriate regions of the brain • Effects • Nerve cell generation delayed • Fewer produced. • Nerve cells don’t go where they are supposed to go. • Unusual cell formations in • hippocampus – learning,memory & emotion • cerebellum – motor ability

  35. 3rd trimester • Interferes with brain growth spurt • Brain weight & head circumference reduced • Fewer cells in cerebellum & hippocampus • These anatomical changes are related to animal equivalent of hyperactivity and learning deficits.

  36. Humans: What can we tell about effect of alcohol on behavior • Early, heavy drinking leads to most severe problems: • mental retardation • sensory deficits (vision, hearing) • motor problems • Facial abnormalities: 1st 8 weeks (comparison of women who stopped or continued: M = 24 drinks per week)

  37. Human Behavior cont. • Even in the absence of physical effects: • learning and attention problems. • Moderate early drinkin leads to more subtle learning difficulties and attention problems. • Hyperactivity, language difficulties, motor deficits greater when Mom drank through pregnancy than stopped after 1st trimester • Weight, length, head circumference affected by drinking later in pregnancy • Being alcohol free during 3rd trimester allows growth catch up.

  38. FASD Adults • The following secondary effects were ascertained from life history interviews of 415 FASD affected individuals using 450 questions • Dr Anne Streissguth, et al, University of Washington www.faseout.ca 2008

  39. Secondary Disabilities • Mental health problems 94% • Disrupted school experiences 43% • Easily victimized 72% • Trouble with the law 60% • Inappropriate sexual behavior 45% • Alcohol and drug problems 50% • Problems parenting • Problems living independently www.faseout.ca 2008

  40. FASD and Activities of Daily LivingStreissguth et al. Longitudinal Study (1996) Sample of adults age 21+ were unable to: • Manage money 82% • Make daily living decisions 78% • Obtain social services 70% • Get medical care 68% • Handle interpersonal relationships 57% • Grocery shop 52% • Cook meals 49% • Structure leisure activities 48% • Stay out of trouble 48% • Maintain hygiene 37% • Use public transportation 24% www.faseout.ca 2008

  41. Implications for intervention • FAS and FAE are common preventable problems. • How can we develop interventions that work? • Type of intervention • Primary, secondary, tertiary • How should be target? • Getting knowledge to people • Motivation to change • Learning from people who have changed

  42. 2. Preventing low birth weight babies • Who has low birthweight babies: • Poverty nexus of risk • Multiple births through infertility treatment

  43. Why? At risk for • medical problems • developmental problems such as cerebral palsy • higher risk of mortality

  44. Role of life style factors in preventing low birth weight

  45. Nutritional and weight gain • Risk factors: • Low income/limited food budgets • Stress and distress • Lack of knowledge about proper nutrition • Smoking, alcohol

  46. Life style choices: Cigarette smoking, alcohol, caffeine, and illegal drugs • Risk factors: • Stress and distress • Lack of knowledge about their effects • Lack of support for stopping addictive behavior • Quitting smoking at any point has positive effect on birth weight.Smoking after birth increases child’s risk of respiratory problems (most women who quit during pregnancy start again after the child’s birth).

  47. Stress • neuroendocrine functioning • depresses immune system • Affects health behaviors • decreases likelihood of prenatal care • increases likelihood of smoking, drinking • Anxiety may increase metabolism • Depression affects appetite, sleep

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