PRENATAL DEVELOPMENT AND BIRTH

1
PRENATAL DEVELOPMENT AND BIRTH
2
THE BEGINNING OF THE LIFE CYCLE

• Fertilization, union of sperm cell and egg
• Zygote forms and begins dividing, travels the
  fallopian tube and implants in the uterus
• 3rd-8th week is called embryo

3
EMBRYONIC GROWTH

• Cells continue to divide, three tissue layers
  eventually form and become systems of the body
• One becomes respiratory and digestive tract
• One becomes muscles, bones, blood vessels and
  skin
• The third becomes nervous system, sense organs
  and mouth

4
TWO STRUCTURES OUTSIDE EMBRYO

• Amniotic sac, surrounds and protects embryo, is
  fluid filled
• Umbilical cord, connects embryo to the placenta
• Placenta, thick blood-rich tissue lining uterus
  provides nutrition
• Nutrients, oxygen to the embryo and wastes from
  the embryo
• Other substances are passed

5
FETAL DEVELOPMENT

• Fertilization, zygote is formed then
• Implantation, cells divide, spinal column, brain,
  ears, arms start forming as well as heart, begins
  to beat (0-2 weeks)
• 3-8 weeks embryo about 1 long
• 9-14 weeks is a fetus now, has human profile

6
DEVELOPMENT

• 15-20 weeks can blink eyes, body growing, can
  grasp and kick
• 21-28 weeks can hear conversations, wakes and
  sleeps 12 long, weighs about a pound, can
  survive if born after 24 weeks
• 29-40 weeks uses all five senses, dreams, about
  266 days is ready for birth
• Trimesters
• 1 0-14 weeks
• 2 15-28 weeks
• 3 29 to birth

7
STAGES OF BIRTH

• In late stages before birth, fetus usually moves
  head to lower part of uterus (cervix)
• Approaching time for birth uterus begins
  contractions, signals onset of labor
• Dilation of cervix (opening of uterus) amniotic
  sac breaks
• Passes through birth canal, starts breathing and
  cries to clear fluid from lungs
• Placenta is pushed from mothers body
  (afterbirth), umbilical cord is cut

8
PRENATAL CARE

• Steps the expectant mother should take as soon as
  she knows shes pregnant to provide for her
  health and that of the baby
• Obstetrician-specialist
• Decide where birth will take place hospital,
  birthing center, home-need doctor/midwife
• Have regular exams
• Ultrasounds
• Amniocentesis?

9
PROPER NUTRITION

• Embryo depends on mother for nourishment
• Calcium-bones, teeth, nerves, muscle
• Protein-muscle and most tissue incl. brain
• Iron-red blood cells and supplies oxygen
• Vitamin A- cell and bone growth, eye development
• Vitamin B complex- nervous system
• Folic acid-spinal fluid, prevention of spinal
  bifida

10
WEIGHT GAIN IN PREGNANCY

• Mothers shouldnt gain too much weight, 25-35
  pounds is a healthy gain for both mother and baby
  (300 extra calories per day)
• Weight reduction diets during pregnancy could
  harm baby
• Caffeine can have negative affects on baby
• Exercise can be beneficial for mother and baby

11
HEALTH OF THE FETUS

• Substances the mother takes in can be passed to
  fetus
• Tobacco, low birth weight, premature birth,
  infant deaths, also negative impact on growth,
  mental development and behavior
• Alcohol, fetal alcohol syndrome (FAS) physical
  and mental defects
• Medicines and drugs (even OTC) wide range of
  health threats to mother and baby, birth defects,
  miscarriages, stillbirth, addictions

12
ENVIRONMENTAL HAZARDS

• Lead-miscarriages, low birth weight,
  mental/behavioral problems
• Smog-birth defects, premature birth stillbirth,
  infant death
• Radiation-x-rays, not color tvs microwaves, etc.
• Cat litter cats-parasite causes toxoplasmosis,
  miscarriage, premature labor, health problems

13
COMPLICATIONS WITH PREGNANCY

• Miscarriage-spontaneous expulsion of fetus before
  20th week
• Stillbirth-dead fetus expelled after 20th week
• Higher risk with tobacco, alcohol, drugs
• Ectopic pregnancy zygote implants in fallopian
  tube, needs to be removed, 1 cause of death in
  1st trimester, STDs cause Preeclampsia-toxemia,
  placenta doesnt get enough blood, treatable
  problem for mother baby

14
HEREDITY AND GENETICS

• Wide variety of traits, heredity is one cause
• Heredity-passing of traits from parent to child
• Eye color, hair color, shape of earlobe, height,
  etc.
• Chromosomes-23 pairs, codes for inherited traits
• Genes-sections of chromosomes are basic units of
  heredity
• DNA chemical unit making up chromosomes

15
GENETICS AND FETAL DEVELOPMENT

• Human cells have 46 chromosomes except sperm and
  egg have 23, when they unit the zygote has 46
• Dominant genes, traits will appear if one is
  present
• Recessive genes, traits will appear only if no
  dominant gene is present
• Some genes represent a quantity-i.e. height
• Gender-egg has only X, sperm X or Y, XXfemale

16
GENETIC DISORDERS

• Mutation or abnormality of genetic code
• Genetic disorders caused by partial or complete
  defect in gene
• Sickle-cell anemia-misshaped cell, clump,
  restricted blood flow, weakness
• Tay-sachs disorder- destruction of nervous system
• Cystic fibrosis-mucus clogs organs incl. lungs,
  liver, etc
• Down syndrome-retardation
• Hemophilia-bleeder

17
TESTING AND TREATMENT

• Most cant be cured, some can be treated
• Amniocentesis-syringe inserted through abdomen
  into amniotic fluid to examine chromosomes
• Chronic villi sampling-small piece of membrane
  that develops into placenta checked for genetic
  disorders
• Can do testing after birth also
• Genetic counseling, probability of genetic
  problems for baby

18
GENETIC RESEARCH TO CURE DISEASE

• Human Genome Project-identify and map genes
• Gene therapy, absence of functioning gene, a
  normal gene can be inserted in some cases
• Genetic engineering-placing a fragment of DNA
  into an organism-experimental
• Genetically engineered drugs-genes inserted into
  other organisms to cause production of substances
  to fight disease

19
INFANCY CHILDHOOD

• Period of dramatic changes
• Erik Erikson, stages, developmental tasks that
  need to occur to move towards being a healthy,
  mature adult
• Based on experiences during that stage
• Partial development can be made up during later
  stages

20
STAGES

• Infancy 0-1 year, fastest growth of life weight
  triples, height gain by 50-TRUST
• Early childhood 1-3 years, learn new skills,
  vocabulary, let child do things-AUTONOMY
• Middle childhood 4-6 years, asking questions,
  initiating activity, parents show approval of
  questions and creativity
• Late childhood 7-12 years school is important,
  getting along with peers, appropriate role in
  society, develop conscience

21
HEALTH SCREENINGS

• Vision and hearing starting with newborns and
  continuing throughout childhood
• 1 of 1,000 children low vision or legally blind
• 2-3 of 1,000 infants born with severe hearing
  problems
• Scoliosis-lateral curvature of spine, more common
  in girls, correctable, sometimes requires surgery