CHAPTER 4 PRENATAL DEVELOPMENT AND BIRTH

Learning Objectives How does development unfold during the prenatal period from conception until the time of birth? How does prenatal behavior of the fetus relate to postnatal behavior of the infant?

Prenatal Development Time of fastest development in life span Environment extremely important Conception –Ova travels from ovary to uterus –Penetration by 1 of sperm –Outcome: Single-celled ZYGOTE

Prenatal Stages Germinal period: Days 1-14 –Implantation: One-half are successful –Miscarriage: 15% to 50% Embryonic period: 3 rd to 8 th week –Organogenesis, Sexual differentiation Fetal period: 9 th week – birth –Proliferation, Migration –Differentiation of stem cells –Ends in tremendous brain development

Learning Objectives How and when do various teratogens affect the developing fetus? How can you summarize the effects of teratogens during the prenatal period? How do maternal age, emotional state, and nutrition affect prenatal and neonatal development? What about the father’s state - can this influence development?

Prenatal Environment Reciprocal influence –Person and environment –Good and bad influences important Teratogen: Environmental agent –Harms the developing fetus –Critical Period: Organogenesis –Dosage and duration –Genetic make-up: Susceptibility

The critical periods of prenatal development. Teratogens are more likely to produce major structural abnormalities during the third through the eighth prenatal week. Note, however, that many organs and body parts remain sensitive to teratogenic agents throughout the nine-month prenatal period

Teratogens: Drugs Thalidomide (for morning sickness) –All or parts of limbs missing Tobacco: Miscarriage, low birth weight, SIDS, slows fetal growth Alcohol: FAS –Small, facial deformities, retardation Cocaine: Processing difficulties

(A) Characteristic features of a child with fetal alcohol syndrome (FAS).

(B) Child with FAS, illustrating many features in the drawing. Such children may also have cardiovascular and limb defects.

Teratogens - Diseases Rubella (German Measles) –Blind, deaf, heart, brain Syphilis: Miscarriage, blind, deaf, heart, brain –After 18 th week AIDS: Mothers transmit to babies (15%-35%) –Prenatally, perinatally, postnatally

Teratogens: Environmental Hazards Radiation: MR, leukemia, cancer, mutations, spontaneous abortions, etc. –Avoid X-rays when pregnant Pollutants –In air and water –Lead: MR (also postnatally)

The Mother’s State Age: Typically age –15 or younger don’t seek prenatal care Birth complications, low birth weight –Over 35:Miscarriage, Down Syndrome (father’s age also) Emotion: Stress can stunt fetal growth –Positive outlook most helpful Nutrition: lb weight gain –Malnutrition: Smaller neurons, brain, child

The three stages of labor: Stage 1: (a) Contractions of the uterus cause dilation and effacement of the cervix. (b) Transition is reached when the frequency and strength of the contractions are at their peak and the cervix opens completely. Stage 2: ( c) The mother pushes with each contraction, forcing the baby down the birth canal, and the head appears. (d) Near the end of Stage 2, the shoulders emerge and are followed quickly by the rest of the baby’s body. Stage 3: (e) With a few final pushes, the placenta is delivered.

The Father’s State Research limited except for genetic contribution Father’s age can also be influential –Over 35: Increased number miscarriages, heart defects, Down Syndrome –Over 50: Higher risk for schizophrenia Exposure to environmental toxins –Radiation, anesthetic gases, pesticides –Damage to genetic material in sperm

Learning Objectives What is the typical perinatal environment like? What hazards can occur during the birth process? What is the birth experience like from the mother’s and father’s perspectives, and from different cultural perspectives?

Newborn

The Perinatal Environment Birth Process: Three step process Possible Hazards –Anoxia: Oxygen shortage: Can be severe –Complicated delivery Cesarean (“C”) section Medications: Can reach baby

The Mother’s Experience Severe pain, anxiety –77% rate it as positive experience Psychological factors –Attitude, knowledge, support Medication: Sedatives, anesthetics, pitocin Cultural factors

Postnatal Depression Baby Blues: mild, common Clinical depression: 1/10 –Previous depression common Children of Depressed Mothers –Insecurely attached, less responsive –Negative to other children

The Father’s Experience Accepted, expected in delivery rooms Attend prenatal classes with wife Experience described as a significant event Anxiety, stress common during delivery Relief, pride, joy when baby is born Sometimes depression following birth –Fathers also need support Disappointed if sex does not resume soon

The Neonatal Environment Culture, early socialization, health status –E.g., low birth-weight babies (8% in US) Less than 5½ lbs Strongly linked to low SES Environment: Neonatal intensive care Risk: Blindness, deafness, CP, autism, cognitive, and later academic problems Parenting must be attentive, responsive

Modern technology permits survival of younger and smaller babies, but many experts believe we have reached the lowest limits of viability at weeks gestation.

Learning Objectives What are the advantages of breast feeding? Are there disadvantages of breast feeding? How can at-risk newborns be identified? What treatments are available to optimize development of at-risk babies? To what extent are the effects of the prenatal and perinatal environments long lasting? What factors influence whether effects are lasting?

Breast or Bottle? Breast feeding most natural nutrition Practices vary across cultures Health benefits great for breast-fed infants –At least first 6 months recommended More likely to bottle feed: Factors –Younger, low SES, less education, employed, African American US values toward breast feeding ambivalent

Low Birth-Weight Babies < 5½ pounds: “Small for date” or “preterm” –Leading cause of infant mortality –8% of all births, 65% of all infant deaths Factors: Low SES, smoking, stress, multiples Worse for minority, poverty, single-parent children For most, significant catch-up growth Low Birth-Weight Infants Greater risk for blindness, deafness, CP, autism, health problems - especially respiratory problems

Factors Helpful for LBW Infants Breastfeeding, skin-to-skin contact, massage Responsive parenting, intellectual stimulation Early intervention programs work with parents –Childcare education and support –Growth-enhancing home environment Consistently attentive, responsive parenting

Risk and Resilience Not all high-risk infants have problems Werner: Kauai Longitudinal study (40 yrs) Findings: –Effects decrease over time –Outcomes depend on postnatal environment –Protective factors Personal resources Supportive postnatal environment