Chapter 4: Prenatal Development Child Development Chapter 4: Prenatal Development

Journal Write down 5 phrases that explain what you know about pregnancy.

State Standards 3.1 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

Video Brain Pop- Reproductive System

Conception Vocabulary Ovum Uterus Fallopian Tube Sperm Conception

Family Planning The 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 Methods Groups 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

Brainpop Video “Genetics”

Genetic 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 Person Family 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 X Sperm cells contain wither X or Y

Brainpop Video “Heredity” Punnett Square Activity

Multiple 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

Infertility Not all people are able to become pregnant 1st step: Doctor evaluates both parent’s help to determine cause Fertility drugs may be prescribed if the cause is eggs are not released every month Several drawbacks: serious side effects, multiple births, etc

Options for Infertility After treatment for infertility some people are still not able to conceive Some 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

Period of the Zygote Lasts about 2 weeks Zygote- fertilized egg Zygote travel down fallopian tube Attaches itself to the lining of the uterus Lining provides nourishment At the end of this period the zygote is only the size of a pin head

Period of the Embryo 3rd-8th weeks of pregnancy Embryo: the developing baby Grows rapidly The mass of cells develop into all the major systems of the human body Brain begins to take control of these systems Amniotic Fluid forms Placenta develops Umbilical Cord forms

Bell Work p. 144- Health Tip Answer questions on own paper to turn in

Period of the Fetus 8th week until birth- about 40 weeks 4th-5th month mother begins to feel baby move- sensations are called “quickening” Fluid grows as fetus grows until just before birth when fluid begins decreasing Baby is swallowing it 7th month- baby capable of living outside womb but only with great medical help 8th and 9th month- organs become ready to survive on their own Fetus can- suck its thumb, cough, sneez, yawn, hiccup, and even cry

Preparing for Birth Baby’s weight begins to shift down in 9th month- “lightening” Fetus is turned upside down in mother’s pelvis Less active Muscles 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.

Brainpop Video “Fetal Development”

A closer Look at Conception Section 5-2 A closer Look at Conception

Brainpop Video “Gender Determination”

Problems in Prenatal Development Section 5-3 Problems in Prenatal Development

For Discussion Excerpt from Helen Keller’s The Story of My Life

Objectives Contrast miscarriage and stillbirth Identify some major birth defects Explain the four causes of birth defects Describe how birth defects can be diagnosed and prevented

Key Terms Amniocentesis Birth Defect Chronic Villi Sampling Miscarriage Stillbirth Ultrasound

Losing a Baby Sometimes babies do not develop normally In some cases the developing baby will die Before 20 weeks- miscarriage After 20 weeks- still birth Loss of an unborn child is devastating to parents As many as 20 percent of al pregnancies end in miscarriage

Types 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 Defects Scientists still don’t understand the cause of all birth defects There are 4 main causes

Environmental Causes During 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 Causes Thousands 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 Chromosomes Some 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 Environment Sometimes 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 Birth Defects Children with birth defects have difficulty leading normal lives The rest of the family is affected too Responsible couples do everything possible to minimize the possibility of birth defects

Genetic Counseling Some 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 Testing More than 100 birth defects can now be found before a baby is born There is not a test to tell if a child will be normal These 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 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

Ask the Experts P. 163

Avoiding Dangers to the Baby Section 5-4 Avoiding Dangers to the Baby

Key Terms Fetal Alcohol effects Fetal Alcohol Syndrome

Objectives Identify the hazards that alcohol and other drugs pose to prenatal development Discuss other environmental hazards that pregnant women should avoid

Alcohol Alcohol is a drug Fetal 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, 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 Drugs Prescription 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 doctor Caffeine- also a drug, can cause birth defects as well, not sure about amounts

Other 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 Rays Radiation can cause birth defects as well Pregnant women should warn medical personnel Always request abdominal shields during x rays

Rubella When 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 Diseases Include: 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