CHAPTER 4
PRENATAL DEVELOPMENT AND BIRTH
PRENATAL DEVELOPMENT
Time of fastest development in life span Environment extremely important Conception
Ova travels from ovary to uterusPenetration by 1 of 300-500 spermOutcome: Single-celled ZYGOTE
PRENATAL STAGES
Germinal period: Days 1-14 Implantation: One-half are successfulMiscarriage: 15% to 50%
Embryonic period: 3rd to 8th weekOrganogenesis, Sexual differentiation
Fetal period: 9th week – birthProliferation, Migration Differentiation of stem cellsEnds in tremendous brain
development
PRENATAL ENVIRONMENT
Reciprocal influencePerson and environmentGood and bad influences
important Teratogen: Environmental agent
Harms the developing fetusCritical Period: OrganogenesisDosage and durationGenetic 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
Cocaine: Processing difficulties
FETAL ALCOHOL SYNDROME (FAS) Male infant born at term and died at 10 weeks due to a sudden
cardiac arrest (see picture at right). The mother's alcohol drinking included up to a gallon of wine at a time several times a week. The child had hydrocephalus (excess water in the brain) and typical facial features of fetal alcohol syndrome (FAS). The cerebellum (which controls coordination and movement) was "extremely small and poorly shaped (see picture at right)." The brainstem (responsible for processes such as breathing and body temperature) was also grossly malformed.
The photograph at left shows the brain of an infant girl who died at 6 weeks. The mother was categorized as a chronic alcoholic. The child’s head circumference was 27 centimeters at birth and did not grow at all during her 6 weeks of life (normal head circumference is approximately 35 centimeters - about 13 and 3/4 inches).
FETAL ALCOHOL SYNDROME
• (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.
FETAL ALCOHOL EFFECTS One of a spectrum of neurological impairments that can
affect a child who has been exposed to alcohol in the womb.
Children with FAE are not as obviously impaired as children diagnosed with Fetal Alcohol Syndrome (FAS) -- usually lack the distinctive FAS facial features and have normal IQs -- and so FAE is sometimes described as less serious.
More likely to have negative outcomes such as trouble with school, trouble with the law and teen pregnancy;
Look "normal" but can't behave that way due to brain damage causes them to face unrealistic expectations without appropriate support.
The term Fetal Alcohol Spectrum Disorder (FASD) is being used more and more to stress the fact that there are a variety of ways in which alcohol can affect a developing child and no particular set of impairments is "better" or "worse."
TERATOGENS: ENVIRONMENTAL HAZARDS
Radiation: MR, leukemia, cancer, mutations, spontaneous abortions, etc.Avoid X-rays when pregnant
PollutantsIn air and waterLead: MR (also postnatally)
THE MOTHER’S STATE
Age: Typically age 16-35 15 or younger don’t seek prenatal care
Birth complications, low birth weightOver 35: Miscarriage, Down Syndrome
Emotion: Stress can stunt fetal growthPositive outlook most helpful
Nutrition: 25-35 lb weight gain Malnutrition: Smaller neurons, brain,
child, schizophrenia
THE FATHER’S STATE
Research limited except for genetic contribution
Father’s age can also be influentialOver 35: Increased number
miscarriages, heart defects, Down Syndrome,
Over 50: Higher risk for schizophrenia & bipolar disorder
Exposure to environmental toxinsRadiation, anesthetic gases,
pesticidesDamage to genetic material in sperm
THE PERINATAL ENVIRONMENT
Birth Process: Three step process Possible Hazards
Anoxia: Oxygen shortage: Can be severe
Complicated deliveryCesarean (“C”) section
Medications: Can reach baby
BREAST OR BOTTLE?
Breast feeding most natural nutrition Practices vary across cultures Health benefits great for breast-fed
infantsAt least first 6 months recommended
More likely to bottle feed:Younger, low SES, less education,
employed, African American US values toward breast feeding
ambivalent
POSTNATAL DEPRESSION
Baby Blues: mild, common Clinical depression: 1/10
Previous depression: more common Children of Depressed Mothers
Insecurely attached, less responsiveNegative 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
LOW BIRTH-WEIGHT BABIES
< 5½ pounds: “Small for date” or “preterm”Leading cause of infant mortality8% 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 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 parentsChildcare education and supportGrowth-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 timeOutcomes depend on postnatal
environmentProtective factors
Personal resourcesSupportive postnatal environment