Prenatal Development and Childbirth

1. Prenatal Development and Childbirth Chapter 3 3

2. Prenatal Development and Childbirth Prenatal Growth and Development Prenatal Environmental Influences Childbirth The Evolving Family

3. Prenatal Growth and Development Prenatal development is divided into three periods: Germinal: 0 to 2 weeks Embryonic: 2 to 8 weeks Fetal: 9 to 38 weeks

4. Prenatal Growth and Development Ovulation occurs about 2 weeks after start of menstrual period The ovum (egg) travels through fallopian tubes, where fertilization may take place If fertilization takes place, a zygote results

5. Two Ways to Describe the Prenatal Period

6. Germinal Period Time of extremely active cell vision Toward end of first week after conception, cells have developed into a blastula, ball of cells around a fluid-filled center Cells begin to differentiate to form supportive structures Twins may develop during the first few divisions of the zygote Monozygotic (identical) twins develop when two identical cells separate and develop into two embryos Dizygotic (fraternal) twins develop when two eggs (ova) are released simultaneously and each unites with a different sperm

7. Ovulation and Fertilization

8. Embryonic Period Beings when implantation is complete Some cells form the embryonic disc, from which the child will develop Other cells will form supportive structures differentiated into the: placenta umbilical cord amniotic sac

9. The Embryo Develops into three distinct layers: Ectoderm: outer layer Will become skin, sense organs, brain, nervous system Mesoderm: middle layer Will become muscles, blood, excretory system Endoderm: inner layer Will become digestive system, lungs, thyroid, thymus, and other organs

10. The Embryo (continued) During the second month, most major body structures develop, except the brain Spontaneous abortions (miscarriages) occur primarily during first trimester, usually by 12 or 13 weeks Often caused by genetic defects or unsuccessful implantation Maternal age, health, nutrition, and exposure to toxic substances, are also risk factors

11. The Fetal Period Lasts from the beginning of third month until birth Organs and systems mature and develop, especially the brain and nervous system At age 24 weeks, the healthy fetus reaches the age of viability, meaning it has a 50% chance of surviving outside the womb if given high-quality intensive care Half of surviving fetuses born at 24 weeks have serious anomalies

12. Week 12 Size: 3 inches long, 1 ounce Arms, legs, and fingers are developed and can move Fingerprints developed Sexual organs developed Vocal cords and taste buds formed Eyes and teeth begin to develop Milestones of Development in the Fetal Period

13. Week 16 Size: 5 1/2 inches long, 4 ounces Heartbeat is stronger and more regular Lanugo develops and covers the body Fingernails and toenails developed Week 20 Size: 10-12 inches long, 8 oz. – 1 pound Senses of taste and smell formed Hair and eyelashes developed Movements can be detected by mother Fetus sucks its thumb Milestones of Development in the Fetal Period

14. Week 24 (age of viability) Size: 11-14 inches long, 1 pound to 1 pound 8 oz. Eyes formed and open Posture straightened and internal organs shift Brain development occurs Week 28 Size: 14-17 inches long, 2 pounds, 8 oz. to 3 pounds Body fat is accumulated Body rhythms developing Brain develops localized centers Fetus can feel pain and touch; responds to sound and vibration Milestones of Development in the Fetal Period

15. Week 32 Size: 16 ½ - 18 inches long, 4-5 pounds Rapid weight gain; body regulation becomes refined Most bones formed Fetus could survive without medical intervention Week 36-38 Size: 19 inches long, 6 pounds Hearing is complete Fetus shifts to “head-down” Vernix caseosa falls away; lanugo dissolves Antibodies are passed from the mother Milestones of Development in the Fetal Period

16. Developmental Trends Three general trends characterize early developmental processes: Cephalocaudal trend Development advances from the head to the feet Proximodistal trend Development proceeds from the middle of the body outward Gross-to-specific trend Responses become more specific as development advances

17. Developmental Trends Three general trends characterize early developmental processes: Cephalocaudal trend Development advances from the head to the feet Proximodistal trend Development proceeds from the middle of the body outward Gross-to-specific trend Responses become more specific as development advances

18. Prenatal Environmental Influences Both genetic defects and environmental influences during the prenatal period or childbirth can result in congenital anomalies Maternal age is linked to increased incidence of congenital anomalies One in 25 mothers over the age of 45 will have a child with Down syndrome Age may be related to age of the ova, which may become damaged over time Hormone levels also shift as women age

19. Maternal Health and Nutrition Maternal malnutrition in pregnancy is linked to: higher rates of spontaneous abortion premature birth stillbirth later difficulties in development Early quality prenatal care is associated with having healthy babies

20. Critical Periods in Prenatal Development A critical period is one during which the developing child is at the greatest risk for harm as a result of teratogens Sometimes exposure to a specific teratogen causes specific harm Or, exposure to certain teratogens may increase overall risk of damage

21. Critical Periods in Prenatal Development

22. Teratogens and Their Effects Viruses (HIV, rubella, the flu) may cross the placental barrier and affect the baby Using HAART therapy and Caesarian delivery, mother-to infant HIV transmission reduced to near zero Certain prescription drugs can cause damage

23. Teratogens and Their Effects Prenatal alcohol exposure: May cause fetal alcohol affects or fetal alcohol syndrome Also increases risk for learning disabilities, attention problems, and hyperactivity No amount of alcohol consumption during pregnancy is safe

24. Video Clip Facts about fetal alcohol syndrome and faces of victims: http://www.youtube.com/watch?v=04IlEeh9vPs

25. Teratogens and Their Effects Marijuana exposure is linked to birth defects, structural defects, and cognitive deficiencies Cigarette smoking may lead to stillbirth, prematurity, spontaneous abortion, low birth weight and cognitive deficits Amphetamine drugs (e.g., cocaine) may damage the nervous system

26. Childbirth Three stages: initial labor labor and delivery afterbirth Childbirth practices vary widely among cultures and generations Many women prefer natural childbirth today, though with medical assistance Birthing centers are becoming more common Cesarean section used in 26% of U.S. births

27. Technological Innovations Allow physicians to detect problems early in pregnancy: Chorionic villus sampling (CVS) Ultrasound Amniocentesis Fetal monitors

28. Video Clip Broadcast news story on 3D and 4D ultrasound technology: http://www.youtube.com/watch?v=ERTgbRnlAQw

29. Complications in Childbirth Breech presentation may require c-section Baby’s general health is evaluated on the 10-point Apgar Scale Prematurity is associated with: Low birth weight Difficulty adjusting after birth Behavioral problems in childhood

30. Video Clip Describes the benefits of kangaroo care: http://www.youtube.com/watch?v=8hLo4_4ksAI

31. The Apgar Scoring System for Newborns

32. Video Clip Description of the Apgar scale: http://www.youtube.com/watch?v=3C6F74Zs1BE

33. The Evolving Family Birth is a psychological and social milestone for the family The transition to parenting can be challenging Pregnancy affects mothers emotionally and psychologically, as well as physically Fathers may feel a greater sense of responsibility and concern about the future

34. Video Clip Describes a nurse-family partnership program in Sacramento County, California that is in danger of being eliminated: http://www.youtube.com/watch?v=PwdiEtExyMg

35. The Newborn The child experiences birth trauma Average full-term newborn weighs between 5 pounds, 8 ounces and 9 pounds, 8 ounces Typically between 19 and 22 inches long May have enlarged genitalia Upon birth, babies make major adjustments to their respiration, circulation, digestion, and temperature regulation

36. The Newborn Babies are born with two types of reflexes Survival Breathing, sucking, rooting, sneezing, gagging Primitive May have had survival value in evolutionary past, these reflexes disappear during first months of life

37. Video Clip Description of the primary reflexes: http://www.youtube.com/watch?v=gyVLD0hl0XY

38. The Newborn Social and emotional processes of the infant will lead to development of attachment Attachment is reciprocal: Extends from infant to caregiver and visa versa For example, breast-feeding is good for mother and baby Infant-caregiver interactions shortly after birth establish the foundation of the attachment relationships that will continue through life

39. Summary Prenatal development is divided into three 3-month trimesters—germinal, embryonic, and fetal Three general trends characterize early development—cephalocaudal, proximodistal, and gross-to-specific Genetic defects and environmental influences (e.g., maternal age, malnutrition, and specific teratogens) can cause birth defects

40. Summary Childbirth is divided into three stages—initial labor, labor and delivery, and afterbirth Childbirth customs vary across cultures Cesarean sections are being increasingly performed, even when not medically necessary Premature is associated with low birth weight and early adjustment difficulties A baby’s general health can be evaluated on a scale called the Apgar Scoring System

41. Summary Birth marks a dramatic transition for newborns, who must make major adjustments to their respiration, circulation, digestion, and temperature regulations Babies are born with survival reflexes Shortly after birth, babies and caregivers engage in behaviors that will lead to attachment Attachment forms the foundation for later social and personality development