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