Berger ca8e lecch4


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Berger ca8e lecch4

  1. 1. Part I Prenatal Development and Birth Chapter Four <ul><li>From Zygote to Newborn </li></ul><ul><li>Risk Reduction </li></ul><ul><li>Birth </li></ul>
  2. 2. From Zygote to Newborn <ul><li>Prenatal development is divided into three main periods: </li></ul><ul><ul><li>germinal period (0-2 weeks) </li></ul></ul><ul><ul><li>embryonic period (3-8 weeks) </li></ul></ul><ul><ul><li>fetal period (9 weeks-birth) </li></ul></ul>
  3. 3. <ul><li>germinal period : </li></ul><ul><ul><li>first two weeks of prenatal development after conception </li></ul></ul><ul><ul><li>Characterized by rapid cell division and the beginning of cell differentiation. </li></ul></ul>Germinal: The First 14 Days
  4. 4. <ul><li>embryonic period : </li></ul><ul><ul><li>approximately the third through eighth week after conception </li></ul></ul><ul><ul><ul><li>all body structures, including internal organs, begin to develop </li></ul></ul></ul><ul><li>fetal period : </li></ul><ul><ul><li>stage of prenatal development from ninth week after conception until birth, during which the organs grow in size and mature in functioning </li></ul></ul>
  5. 5. Germinal: The First 14 Days <ul><li>implantation: </li></ul><ul><ul><li>process in which developing organism burrows into placenta that lines uterus </li></ul></ul><ul><li>placenta : </li></ul><ul><ul><li>organ that surrounds developing embryo and fetus, sustaining life via the umbilical cord </li></ul></ul>
  6. 6. <ul><li>Embryo: </li></ul><ul><ul><li>name for a developing human organism from about the third through the eighth week after conception </li></ul></ul>Embryo: From the Third Through the Eighth Week
  7. 7. <ul><li>The developing organism is called a fetus from the start of the ninth week after conception until birth. </li></ul><ul><li>during the fetal period the fetus develops from tiny, sexless creature to a 7 1/2-pound, 20-inch boy or girl </li></ul>Fetus: From the Ninth Week Until Birth
  8. 8. <ul><li>At the end of the third month, the fetus has all its body parts. </li></ul><ul><li>Weighs approximately 3 ounces, and is about 3 inches long. </li></ul><ul><li>Early prenatal growth is very rapid, but there is considerable variation from fetus to fetus, especially in body weight. </li></ul>The Third Month
  9. 9. <ul><li>In the fourth, fifth and sixth months: </li></ul><ul><ul><li>heartbeat becomes stronger </li></ul></ul><ul><ul><li>cardiovascular system becomes more active </li></ul></ul><ul><ul><li>brain increases about six times in size </li></ul></ul>
  10. 10. <ul><li>age of viability : </li></ul><ul><ul><li>Age at which a fetus can survive outside the mother’s uterus if specialized medical care is available. </li></ul></ul><ul><ul><li>about 22 weeks after conception </li></ul></ul><ul><li>In the final three months of prenatal life: </li></ul><ul><ul><li>brain waves indicate responsiveness. </li></ul></ul><ul><ul><li>lungs expand and contract, using the amniotic fluid as a substitute for air. </li></ul></ul><ul><ul><li>heart valves, arteries, and veins circulate the fetal blood. </li></ul></ul>
  11. 12. Risk Reduction <ul><li>teratogens: agents and conditions that can: </li></ul><ul><ul><li>harm the prenatal brain </li></ul></ul><ul><ul><li>impairing the future child’s intellectual and emotional functioning </li></ul></ul>
  12. 13. <ul><li>Once it was thought the placenta screened out all harmful substances. </li></ul><ul><ul><li>Doctors on an Australian military base traced an increase in blindness among newborns to rubella (German measles) contracted by pregnant women a few months earlier. </li></ul></ul><ul><ul><li>Realized that some diseases during pregnancy could harm a fetus. </li></ul></ul>Determining Risk
  13. 14. <ul><li>The effort to understand what triggered such damage gave rise to: </li></ul><ul><ul><li>teratology: science of risk analysis, the study of birth defects </li></ul></ul><ul><ul><li>risk analysis : to determine likelihood of harm, science of weighing the potential effects of a particular: </li></ul></ul><ul><ul><ul><li>event </li></ul></ul></ul><ul><ul><ul><li>substance </li></ul></ul></ul><ul><ul><ul><li>experience </li></ul></ul></ul>
  14. 15. Timing of Exposure
  15. 16. <ul><li>Second important factor is the dose and/or frequency of exposure. </li></ul><ul><ul><li>threshold effect: situation in which a certain teratogen is relatively harmless in small doses but harmful once exposure reaches certain level (the threshold) </li></ul></ul><ul><ul><li>interaction effect: result of a combination of teratogens </li></ul></ul><ul><ul><ul><li>Sometimes risk is greatly magnified when embryo or fetus is exposed to more than one teratogen at the same time. </li></ul></ul></ul>
  16. 17. <ul><li>Genetic Vulnerability </li></ul><ul><li>Several lines of evidence suggest that genes may be crucial. </li></ul><ul><ul><li>Dizygotic twins, exposed to same teratogens but have only half their genes in common, are born with different abnormalities. </li></ul></ul><ul><ul><ul><li>Suggests both protective and vulnerable genes. </li></ul></ul></ul><ul><ul><li>Cleft lip, cleft palate, club foot more common in some families. </li></ul></ul><ul><ul><ul><li>Suggests genetic vulnerability. </li></ul></ul></ul>
  17. 18. <ul><li>Protective Measures </li></ul><ul><li>Impact of teratogens cannot be predicted before mid-pregnancy. </li></ul><ul><li>Some pregnant women are exposed to the tetragons with no evident harm. </li></ul><ul><li>Some defects occur even thought the woman avoids all known tetragons while pregnant. </li></ul>
  18. 19. A View From Science <ul><li>Alcohol in high doses is a proven teratogen. </li></ul><ul><li>40 years ago drinking during pregnancy was believed to be harmless. </li></ul><ul><li>Obstetricians noted that some patients who drank heavily while they were pregnant had babies with distorted faces. </li></ul><ul><ul><li>fetal alcohol syndrome (FAS) </li></ul></ul><ul><ul><li>fetal alcohol effects (FAE) </li></ul></ul>
  19. 20. <ul><li>fetal alcohol syndrome (FAS) : cluster of birth defects, including: </li></ul><ul><ul><li>abnormal facial characteristics </li></ul></ul><ul><ul><li>slow physical growth </li></ul></ul><ul><ul><li>retarded mental development </li></ul></ul><ul><li>fetal alcohol effects (FAE) : condition in which child has been exposed to alcohol before birth </li></ul><ul><ul><li>has some signs of fetal alcohol syndrome but does not meet all the criteria </li></ul></ul>
  20. 21. <ul><li>Benefits of Prenatal Care </li></ul><ul><li>Tests done during pregnancy can diagnose problems early on, and remedies can be put in place in some instances. </li></ul><ul><li>sonogram : image of unborn fetus (or an internal organ) produced by high-frequency sound waves (ultrasound) </li></ul>
  21. 22. <ul><li>For full-term fetus and a healthy mother, birth can be simple and quick. </li></ul>
  22. 23. <ul><li>The Newborn’s First Minutes </li></ul><ul><li>Most newborns begin to breathe as soon as their head emerges. </li></ul><ul><ul><li>first breath causes infant’s color to change </li></ul></ul><ul><ul><li>eyes open wide </li></ul></ul><ul><ul><li>the tiny fingers grab </li></ul></ul><ul><ul><li>toes stretch and retract </li></ul></ul><ul><ul><li>mucus in the baby’s throat is removed </li></ul></ul><ul><ul><li>umbilical cord is cut to detach the placenta </li></ul></ul><ul><ul><li>placenta is expelled </li></ul></ul>
  23. 24. <ul><li>Apgar scale : quick assessment of newborn’s condition including: </li></ul><ul><ul><li>the baby’s color </li></ul></ul><ul><ul><li>heart rate </li></ul></ul><ul><ul><li>reflexes </li></ul></ul><ul><ul><li>muscle tone </li></ul></ul><ul><ul><li>respiratory effort </li></ul></ul>
  24. 25. <ul><li>Medical Intervention </li></ul><ul><li>about 31% of births in the U.S. are cesarean section, (also called c-section) </li></ul><ul><ul><li>incision through mother’s abdomen and uterus to allow fetus to be removed quickly, instead of being delivered through the vagina </li></ul></ul>
  25. 26. <ul><li>Birth In Developing Nations </li></ul><ul><li>In the U.S. only 1% of births take place at home. </li></ul><ul><li>Worldwide most births occur at home. </li></ul><ul><li>doula - a woman who helps with the birth process </li></ul><ul><ul><li>- also helps with breastfeeding and newborn care. </li></ul></ul>
  26. 27. <ul><li>anoxia: </li></ul><ul><ul><li>lack of oxygen that can cause brain damage or death to the baby </li></ul></ul><ul><ul><li>means “no oxygen” </li></ul></ul><ul><li>cerebral palsy: </li></ul><ul><ul><li>disorder that results from damage to brain’s motor centers </li></ul></ul><ul><ul><li>People with cerebral palsy have difficulty with muscle control, so their speech and body movements are impaired. </li></ul></ul>Anoxia
  27. 28. <ul><li>Average weight of a newborn is 7½ lbs. </li></ul><ul><ul><li>low birthweight (LBW): a body weight at birth of less than 5½ lbs . </li></ul></ul><ul><ul><li>very low birthweight (VLBW): a body weight at birth of less than 3 lbs, 5oz . </li></ul></ul><ul><ul><li>extremely low birthweight (ELBW): a body weight at birth of less than 2 lbs, 3 oz . </li></ul></ul>Low Birthweight (LBW)
  28. 29. <ul><li>preterm birth : occurs 3 or more weeks before full 38 weeks of a typical pregnancy </li></ul><ul><ul><li>Preterm babies are typically (but not always) LBW because they miss final weeks of weight gain. </li></ul></ul><ul><ul><li>small for dates or small for gestational age (SGA)- birth weight is lower than expected given the time of conception . </li></ul></ul>
  29. 30. <ul><li>Social Support </li></ul><ul><li>The developing person is affected by quality of: </li></ul><ul><ul><li>medical care </li></ul></ul><ul><ul><li>education </li></ul></ul><ul><ul><li>culture </li></ul></ul><ul><ul><li>social support </li></ul></ul><ul><li>Fathers and other relatives, neighbors, cultures, and, clinics can reduce risk of birth complications </li></ul>
  30. 31. <ul><li>Mothers, Fathers, and a Good Start </li></ul><ul><li>Birth complications can have a lingering impact on the new family, depending partly on: </li></ul><ul><ul><li>sensitivity of hospital care </li></ul></ul><ul><ul><li>the home </li></ul></ul><ul><li>To reduce stress on an infant who has to stay in the hospital, parents are encouraged to help with early caregiving. </li></ul>
  31. 32. <ul><li>kangaroo care : form of child care in which the mother of a low-birthweight infant spends at least an hour a day holding the baby between her breast, like a kangaroo </li></ul>
  32. 33. <ul><li>Help from Fathers </li></ul><ul><li>Fathers can be crucial in the effort to produce a healthy baby. </li></ul><ul><li>Supportive father-to-be helps a mother-to-be: </li></ul><ul><ul><li>stay healthy </li></ul></ul><ul><ul><li>well nourished </li></ul></ul><ul><ul><li>drug-free </li></ul></ul>
  33. 34. <ul><li>parental alliance : cooperation between a mother and a father based on mutual commitment to their children </li></ul><ul><li>Parents agree to support each other in their shared parental roles. </li></ul>
  34. 35. <ul><li>new mother’s feelings of inadequacy and sadness in days and weeks after giving birth including: </li></ul><ul><ul><li>irritability </li></ul></ul><ul><ul><li>eating disruptions </li></ul></ul><ul><ul><li>sadness </li></ul></ul><ul><ul><li>feeling overwhelmed and inadequate </li></ul></ul><ul><li>affects 10-15% of women </li></ul>Postpartum Depression
  35. 36. <ul><li>parent-infant bond: strong, loving connection that forms as parents hold, examine, and feed newborn </li></ul><ul><li>cross-fostering: newborns are removed from their biological mothers in first days of life and raised by another female or even male </li></ul>Bonding