1. Child Psychology: The Modern Science, 3e by Vasta, Haith, and Miller Paul J. Wellman Texas A&M University John Wiley and Sons, Inc. © 1999 PowerPoint  Presentation: Chapter 5 Prenatal Development

2. © 1999 John Wiley and Sons, Inc.Vasta, 3e Fig.5.1 An 17th Century View of Conception

3. © 1999 John Wiley and Sons, Inc.Vasta, 3e Fig. 5.2 Prenatal Development: Period of the Zygote

4. © 1999 John Wiley and Sons, Inc.Vasta, 3e Fig. 5.4 Prenatal Development: Period of the Embryo (Figure adapted with permission from Textbook of Embryology, 5th ed. (p. 87), by H.E. Jordan and J.E. Kindred, 1948, New York: Appleton-Century-Crofts.Copyright © 1948 by Appleton-Century-Crofts.)

5. © 1999 John Wiley and Sons, Inc.Vasta, 3e Fig. 5.5 Prenatal Environment

6. © 1999 John Wiley and Sons, Inc. Period of the Fetus n From prenatal weeks 9-38, the embryo is termed a fetus n This phase is characterized by –Further increases in size and weight –Appearance of nails and bone –Further development of the brain –Movement and behavior –Increasing levels of fat in skin (thermal protection)

7. © 1999 John Wiley and Sons, Inc. Teratology n Teratogens refer to agents that cause abnormal development in the fetus –Teratogens can have physical effects (malformation) or psychological effects (intelligence, temperament, activity) n Classes of teratogens include –Drugs –Infectious diseases –Mother’s age –Poor nutrition –Other environmental agents

8. © 1999 John Wiley and Sons, Inc. Principles of Teratology 1. The effect of a teratogen depends on the genetic makeup of the exposed organism 2. Teratogen effects on development depend on timing (period of 2-8 weeks is particularly sensitive) 3. The effect of a teratogen may be unique 4.The impact of teratogens may be severe 5. Teratogens differ in how they gain access to the fetus 6.Teratogen dosage is related to degree of abnormal development

9. © 1999 John Wiley and Sons, Inc. Consequences of Teratogens Street DrugsBabies of drug-addicted mothers are born addicted and are likely to have developmental problems TherapeuticsDrugs such as thalidomide may induce abnormalities CaffeineSome risk is associated with caffeine NicotineCan affect growth, increase risk of premature delivery AlcoholCan lead to Fetal Alcohol Syndrome EnvironmentalMercury, lead, and PCBs are harmful Chemicalsto the fetus

10. © 1999 John Wiley and Sons, Inc. Natural Teratogens n Maternal infectious diseases –Rubella can damage the CNS of the fetus, sensitive period is 2-8 weeks –Herpes virus can cause brain abnormalities and blindness –HIV can produce facial abnormalities n Nutrition –Poor prenatal nutrition results in unfavorable development, low brain weight, and higher rates of spontaneous abortion

11. © 1999 John Wiley and Sons, Inc.Vasta, 3e Fig. 5.6 Parental Age Effects (Figure reprinted with permission from: “Paternal Age Effect” by J.M. Friedman, Obstetrics and Gynecology, vol 57, 1981, p 746.)

12. © 1999 John Wiley and Sons, Inc. Fetal Alcohol Syndrome n Alcohol is the most widely used drug known to harm the fetus –Third major cause of birth defects –Leading cause of congenital mental retardation n Consumption of alcohol during pregnancy can result in Fetal Alcohol Syndrome (FAS) Constellation of limb and facial deformations, failure to thrive, mental retardation, and learning disabilities Chronic use of alcohol increases the risk of FAS to 50%; Risks associated with low levels of alcohol are unknown

13. © 1999 John Wiley and Sons, Inc. Screening Methods n Ultrasound Imaging: Uses ultrasound to monitor the development of the fetus n Amniocentesis: Samples amniotic fluids for cells that are examined for markers of genetic defects n Chorionic Villus Sampling: Collects cells from a portion of the placenta for genetic analysis n Test-tube Screening: In vitro embryos can be screened for genetic defects

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