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CHAPTER 4

PRENATAL DEVELOPMENT AND BIRTH

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Learning Objectives

How does developmentunfold during the

prenatal period from

conception until thetime of birth?

How does prenatalbehavior of the fetus

relate to postnatalbehavior of the infant?

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Prenatal Development

Time of fastest developmentin life span

Environment extremely

important Conception

Ova travels from ovary to

uterus

Penetration by 1 of 300-

500 sperm

Outcome: Single-celled

ZYGOTE

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Prenatal Stages

Germinal period: Days 1-14 Implantation: One-half are

successful

Miscarriage: 15% to 50%

Embryonic period: 3rd to 8th week Organogenesis, Sexual

differentiation

Fetal period: 9th week birth

Proliferation, Migration Differentiation of stem cells

Ends in tremendous brain

development

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Learning Objectives

How and when do variousteratogens affect the

developing fetus?

How can you summarize theeffects of teratogens during theprenatal period?

How do maternal age,emotional state, and nutrition

affectprenataland neonataldevelopment?

What about the fathers state -can this influence

development?

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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

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The critical periods of prenatal development. Teratogens are more likely toproduce major structural abnormalities during the third through the eighth

prenatal week. Note, however, that many organs and body parts remainsensitive to teratogenic agents throughout the nine-month prenatal period

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Teratogens: Drugs

Thalidomide (for morningsickness)

All or parts of limbs missing

Tobacco: Miscarriage, low birthweight, SIDS, slows fetal growth Alcohol: FAS

Small, facial deformities,

retardation

Cocaine: Processing difficulties

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

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

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Teratogens - Diseases

Rubella (GermanMeasles)

Blind, deaf, heart, brain

Syphilis: Miscarriage,blind, deaf, heart, brain After 18th week

AIDS: Mothers transmit tobabies (15%-35%)

Prenatally, perinatally,

postnatally

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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)

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The Mothers State

Age: Typically age 16-35 15 or younger dont seek prenatal

care

Birth complications, low birth

weight Over 35:Miscarriage, Down

Syndrome (fathers age also)

Emotion: Stress can stunt fetal growth

Positive outlook most helpful

Nutrition: 25-35 lb weight gain Malnutrition: Smaller neurons,

brain, child

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The three stages of labor: Stage 1: (a) Contractions of the uterus cause dilation andeffacement of the cervix. (b) Transition is reached when the frequency and strength of thecontractions are at their peak and the cervix opens completely. Stage 2: ( c) The motherpushes 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 thebabys body. Stage 3: (e) With a few final pushes, the placenta is delivered.

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The Fathers State

Research limited except forgenetic contribution

Fathers 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

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Learning Objectives

What is the typicalperinatalenvironment

like?

What hazards can occur

during the birth

process?

What is the birthexperience like from the

mothers and fathersperspectives, and from

different cultural

perspectives?

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Newborn

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The Perinatal Environment

Birth Process: Three stepprocess

Possible Hazards

Anoxia: Oxygenshortage: Can be

severe

Complicated delivery

Cesarean(C)section

Medications: Can reachbaby

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The Mothers Experience

Severe pain, anxiety 77% rate it as

positive experience

Psychological factors Attitude, knowledge,

support

Medication: Sedatives,anesthetics, pitocin

Cultural factors

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The Fathers Experience

Accepted, expected in delivery rooms Attend prenatal classes with wife Experience described as a significant

event Anxiety, stress common duringdelivery

Relief, pride, joy when baby is born

Sometimes depression following birth Fathers also need support Disappointed if sex does not resume

soon

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The Neonatal Environment

Culture, early socialization, health status E.g., low birth-weight babies (8% in US)

Less than 5 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

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Modern technology permits survival of younger and smaller babies, but many experts believe we

have reached the lowest limits of viability at 23-24 weeks gestation.

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Low Birth-Weight Babies

< 5 pounds: Small for date orpreterm 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

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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

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Risk and Resilience

Not all high-risk infants haveproblems

Werner: Kauai Longitudinalstudy(40 yrs)

Findings: Effects decrease over time

Outcomes depend onpostnatal environment

Protective factors

Personal resources Supportive postnatal

environment