child development chapter 4: prenatal development
TRANSCRIPT
State StandardsState Standards3.1 Analyze hereditary and
environmental factors affecting prenatal development beginning with conception
3.2 Analyze maternal and paternal health and environmental factors affecting conception and prenatal development
Family PlanningFamily PlanningThe only 100% method of
contraception is abstinence An ovum usually lives 12-24
hours A sperm usually lives 48-72 hours There are approximately 3-4
days in which intercourse could lead to conception
Contraceptive MethodsContraceptive MethodsGroups 1-2 Each group will have 1 method. Your responsibilities:
◦Find a picture of an example of that method
◦Turn picture into the assignment turn in folder
◦Give a 30 second spill about that method and show picture
Grade: Assignment worth 20 points◦5 points for picture◦10 points for spill◦5 points for professionalism
Genetic PackageGenetic Package
Each person inherits characteristics from parents
Chromosomes: tiny threadlike particles in the nucleus of every cell◦ Human babies receive 46 at conception- 23 pairs◦ Each chromosomes has thousands of genes: the units
that determine inherited characteristics◦ For every inherited characteristic a person receives two
copies of a gene- mother and father◦ Dominant Gene: stronger◦ Recessive Gene: weaker◦ Genome: The complete blueprint for the creation of a
person
Making a Unique PersonMaking a Unique PersonFamily often times look alike
because of the gene combinations
Sex of a child is also determined at conception
Two types of sex chromosome: X and Y
Egg cells contain XSperm cells contain wither X or Y
JournalJournalWhat is infertility?Name two other options an
infertile mother would have?What is the difference between
identical and fraternal twins?
Multiple BirthsMultiple Births
Identical Twins: Fertilized egg divides into two separate babies
Fraternal Twins: two eggs are released at the same time and both are fertilized
2.5% of births are multiple births◦More than 2 babies is even more rare◦Most of the time multiple births (more than
2) results from treatment of infertility: the inability to become pregnant
InfertilityInfertilityNot all people are able to
become pregnant1st step: Doctor evaluates both
parent’s help to determine causeFertility drugs may be prescribed
if the cause is eggs are not released every month◦Several drawbacks: serious side
effects, multiple births, etc
Options for InfertilityOptions for InfertilityAfter treatment for infertility some
people are still not able to conceiveSome options:
◦ Adoption◦ Artificial Insemination: sperm injected into
woman’s uterus◦ In vitro Fertilization: Egg is fertilized outside
body and then placed in the woman’s uterus◦ Ovum Transfer: egg from female donor then
fertilized◦ Surrogate Mother
Three Stages of Three Stages of PregnancyPregnancyPrenatal Development: the
baby’s development during pregnancy
Germinal StageEmbryonic StageFetal Stage
Germinal StageGerminal StageZygote: The fertilized eggLasts only about 2 weeksCell Division
◦Cell begins to grow while it is still in the fallopian tube
◦After about 4 days the zygote reaches the uterus
Implantation After about 2 weeks of growth the
zygote is about the size of a pin head
Embryonic StageEmbryonic Stage Embryo: developing baby from weeks 3-8 Organs and Body Systems:
◦ All the major system develop in this stage◦ Brain begins to take control◦ Brain is sensitive to damage from drugs and alcohol
Amniotic Sac Amniotic Fluid Placenta: Tissue that connects the developing baby to
the uterus Umbilical Cord: long tube that connects the baby to
the placenta Placenta and Umbilical cord are responsible for taking
waste away from and bringing nutrients to embryo
Fetal Stage Fetal Stage Fetus: developing baby during the
fetal stageVocal chords developDigestive system and kidneys begin
to functionMovements are possible by the end
of the 3rd monthBy 7th month fetus is capable of
living outside uterus but will require medical intervention
Preparing for BirthPreparing for Birth
Baby’s weight begins to shift down in 9th month- “lightening”
Fetus is turned upside down in mother’s pelvis
Less activeMuscles of the uterus and abdomen
can be stretched up to 60 times their original size!◦Return to original size in about 6 weeks
after pregnancy.
JigsawJigsawDescribe what happens during
fetal development for given month in pregnancy◦Size of fetus◦Organs developed◦Important Developments
ObjectivesObjectivesContrast miscarriage and
stillbirthIdentify some major birth defectsExplain the four causes of birth
defectsDescribe how birth defects can
be diagnosed and prevented
Losing a BabyLosing a BabySometimes babies do not
develop normallyIn some cases the developing
baby will dieBefore 20 weeks- miscarriageAfter 20 weeks- still birthLoss of an unborn child is
devastating to parentsAs many as 20 percent of al
pregnancies end in miscarriage
Types of Birth DefectsTypes of Birth Defects
Birth defect- serious problems that threatens a child’s health or ability to live
About 3 out of 100 children are born with a birth defect
Birth defects affect:◦ Shape or size of the body or of certain parts of the
body◦ A part or system of the body does not work properly
Not all birth defects are apparent at birth
Causes of Birth DefectsCauses of Birth DefectsScientists still don’t understand
the cause of all birth defectsThere are 4 main causes
Environmental CausesEnvironmental CausesDuring the first few weeks of
conception all the baby’s major systems develop
Things that affect the development of the baby include:◦ Nutritional balance of the mother’s diet◦ Diseases or infections the mother has ◦ Harmful substances the mother takes in◦ Some medicines◦ Exposure to outside hazards such as radiation
Hereditary CausesHereditary CausesThousands of genes make up a genetic
blueprint- each person has about 5-6 imperfect recessive genes
A single copy of this defective gene- no effect
2 copies of this gene=birth defect or a dominant defective gene=birth defect
Some inherited conditions affect only one sex◦ Ex- Hemophilia (prevents blood from clotting)
and color blindness
Errors in ChromosomesErrors in ChromosomesSome birth defects are linked to a
problem with the baby’s chromosomes◦Ex- too many or too few chromosomes
The child does not inherit this condition
Most common is down syndrome◦1 child in every 800 births has down
syndrome◦Risk is higher in mothers over 35◦Child has an extra chromosome 21
Interaction of Heredity and Interaction of Heredity and EnvironmentEnvironmentSometimes birth defects result
from heredity and environment combined◦Ex- A baby may inherit the tendency
for a heart defect but only appears if some factor- such as a drug or virus- affects the baby during development
Researchers think this is probably the cause of cleft lip and spina bifida
Prevention and Diagnosis of Prevention and Diagnosis of Birth DefectsBirth DefectsChildren with birth defects have
difficulty leading normal livesThe rest of the family is affected
tooResponsible couples do
everything possible to minimize the possibility of birth defects
Genetic CounselingGenetic CounselingSome people seek genetic counseling
◦ May or may not already have a child with a birth defect
Does not tell people what to do, only explains risks and options
Family doctors can perform this service, but is best provided by a specialist
The genetic counselor first gathers family histories from the couple
Then they are given thorough medical examinations and sometimes tests
Prenatal TestingPrenatal TestingMore than 100 birth defects can now be
found before a baby is bornThere is not a test to tell if a child will
be normalThese tests can alert the physician of
problems; many times they can be taken care of before birth or immediately following birth
Sometimes blood testing can reveal birth defects
Types of Prenatal TestsTypes of Prenatal Tests
Ultrasound- checks for specific health problems◦ Can show if the fetus is developing on schedule◦ Can confirm due date
Amniocentesis- Process of withdrawing a sample of amniotic fluid and then testing it for indications of birth defects◦ About 1 out of 200 amniocentesis tests result in
miscarriage Chronic Villi Sampling- Tests a small amount of the
tissue surrounding the fetus◦ Guided by a ultrasound image the doctor inserts a small
tube throught the woman’s vagina into the uterus; the samples are then obtained by snipping or suction
◦ Risk of miscarriage or birth defect is mush higher than amniocentesis
ObjectivesObjectivesIdentify the hazards that alcohol
and other drugs pose to prenatal development
Discuss other environmental hazards that pregnant women should avoid
AlcoholAlcohol
Alcohol is a drugFetal Alcohol Syndrome- a pregnant
woman who drinks is at risk for her child developing FAS◦Includes physical and mental problems◦1 in 5 babies with FAS die soon after birth◦Almost all are mentally retarded◦Other problems: slow growth, poor
coordination, heart defects, and facial disfigurement
◦Also, learning disabilities and hyperactivity
Alcohol, continuedAlcohol, continued
Fetal Alcohol Effects- less severe than FAS, but still suffers from some of the same problems
Severity depends on amount consumed by mother, stage of pregnancy, and presence of other drugs in the mother’s system
Can be prevented by not drinking!It is not know how much alcohol will
cause the syndrome
Other DrugsOther DrugsPrescription and over the counter
drugs◦No such thing as a completely safe drug◦First 3 months are most critical◦Last 6 months- slowed growth,
infections, and bleeding at birth◦Meds should not be taken unless
approved by the doctorCaffeine- also a drug, can cause
birth defects as well, not sure about amounts
Other Drugs, continuedOther Drugs, continued
Tobacco- the more a mother smokes the smaller the baby will be ◦ Heavy smoking can cause premature birth◦ Linked to respiratory infections, allergies, and asthma
Illegal Drugs- a mother who is addicted to an illegal drug normally passes the addiction to the baby◦ After birth the baby must go through withdrawal,
some babies die◦ Long-term effects may be serious, many of these
children have problems following directions and learning disabilities
X RaysX RaysRadiation can cause birth defects
as wellPregnant women should warn
medical personnel Always request abdominal
shields during x rays
RubellaRubellaWhen a pregnant woman
contracts rubella babies can suffer with deafness, blindness, heart disease, or mental retardation
Vaccines are available but can be dangerous for women who are pregnant or become pregnant shortly after the shot
Sexually Transmitted Sexually Transmitted DiseasesDiseasesInclude: Syphilis, Gonorrhea,
Hepatitis B, Genital Herpes, AIDS, Group B Streptococcus, Chlamydia
Can be passed from mother to child
Can result in death or other birth defects
You can have a STD without knowing it!
AIDS- the virus that causes AIDS can be passed from mother to child