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Chapter 4: Prenatal Development

Chapter 4: Prenatal Development. 4.1 The Developing Baby 4.2 Problems in Prenatal Development 4.3 Avoiding Dangers to the Baby. Chapter 4 Objectives. List the methods of family planning Outline what occurs during each of the three stages of prenatal development

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Chapter 4: Prenatal Development

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  1. Chapter 4: Prenatal Development 4.1 The Developing Baby 4.2 Problems in Prenatal Development 4.3 Avoiding Dangers to the Baby

  2. Chapter 4 Objectives List the methods of family planning Outline what occurs during each of the three stages of prenatal development Contrast miscarriage and stillbirth Identify how ten major birth defects can be diagnosed Summarize the hazards that alcohol and other drugs pose to prenatal development Assess why environmental hazards must be avoided during pregnancy Describe how a fetus can be affected by certain illnesses the mother may contract

  3. The Developing Baby Chapter 4 Section 1

  4. Family Planning Many families carefully consider whether to have children and when to have them. However, anytime a couple has sexual intercourse, a pregnancy can occur. The only sure way to prevent pregnancy is abstinence, or avoiding sexual activity. Do you think this statement is true or false?

  5. Conception • About every 28 days, an ovum (egg) is released by one of a woman’s two ovaries. • This is called ovulation; at the same time certain hormones are released • During ovulation, the inner lining of the uterus grows and thickens. • If the ovum is not fertilized, the lining breaks down and passes out of the body • The menstrual period • When an ovum is released it travels through the fallopian tube (connects the ovary to the uterus) • This journey takes about 2-3 days

  6. Conception • When the ovum reaches the uterus unfertilized, it typically breaks up • When a sperm, the male cell, reaches the fallopian tube it may penetrate and fertilize the ovum • The process when the sperm fertilizes the egg is called conception • Ovum's usually live 12-24 hours while sperm are capable of fertilizing an ovum for about 48 to 72 hours • During a woman’s cycle, there are only about 3-4 days in which conception can occur

  7. Conception

  8. The Role of Genetics • People inherit many physical traits from their parents • Skin color • Hair color and texture • Eye color • Size and shape of ears • Much more… • Some children are more likely to have talents like musical talents or athletic ability

  9. The Role of Genetics • At the moment of conception, every human baby receives 46 chromosomes • A chromosome is a tiny threadlike structure in the nucleus of every cell • Chromosomes come in 23 pairs • The fathers sperm and mothers ovum contribute 1 to each pair • Has hundreds to thousands of gene • A gene is a unit that determines a human’s inherited characteristics • The complete blueprint for the creation of a person is called a genome • The complex molecules that make up genes are called DNA

  10. Dominant and Recessive Genes Dominant Recessive A recessive gene is a weaker one and will not be expressed • A dominant gene is a stronger gene • The terms dominant and recessive only refer to the relationship of genes to each other • What factor determines the characteristic that a person will express is the dominant gene • EX: Red hair genes often skip a generation because the gene is recessive • Most traits are influenced by multiple genes • Height, weight, personality, and intelligence

  11. Let’s Practice

  12. Making a Unique Person • Heredity explains why people in some families look so much alike and why some do not • EX: one child with brown hair and another with bright blond hair • The gender of the child is determined at conception • Sex chromosomes come in two types X and Y • Woman carries the X, and the man carries the X or Y

  13. 1st Month • At 2 weeks: size of a pin head • Egg attaches to the lining of the uterus • Critical stage for brain and spinal cord development • Internal organs and circulatory system begin to form • The heart begins to beat

  14. 2nd Month • Size about ¼” long at the beginning of the month • Face, eyes, ears, and limbs take shapes • Bones begin to form

  15. 3rd Month • Size about 1” as the month begins • Nostrils, mouth, lips, and eyelids form • Buds for all 20 baby teeth appear • Fingers and toes almost complete • All organs present but still immature

  16. 4th Month • About 3” long; weighs 1 ounce as the month begins • Can suck its thumb, swallow, hiccup, and move around • Facial features become clearer

  17. 5th Month • About 6 ½’-7” long and weighs 4-5 oz as month begins • Hair, eyelashes, and eyebrows appear • Teeth continue to develop • Organs are maturing • Becomes more active

  18. 6th Month • Size about 8-10” long and weighs 8-12 oz. as the month begins • Fat deposits under skin, but fetus appears wrinkled • Breathing movements begin

  19. 7th Month • Size about 10-12” long and weighs 1 ½-2 lbs as month begins • Has periods of activity followed by periods of rest and quiet

  20. 8th Month • Size about 14-16” long, 2 ½-3 lbs as the month begins • May react to loud noises with a reflex jerking action • Moves into a head-down position

  21. 9th Month • Size about 17-18” long and weighs about 5-6 lbs as month begins • Weight gain continues • Skin becomes smooth as fat deposits continue to form • Movements decrease as the fetus has less room to move around • Acquires disease-fighting antibodies from the mother’s blood • Descends into pelvis, ready for birth

  22. Chapter 4 Section 2 Problems in Prenatal Development

  23. Losing a Baby • Sometimes a baby does not develop normally • Sometimes the developing baby dies • Miscarriage is when a baby dies prior to the 20th week of pregnancy • Still birth is when a baby dies after the 20th week of pregnancy • About 15% of recognized pregnancies end in miscarriage • Causes are still not medically known • Still birth occurs in about 2% of pregnancies • Most common causes are problems with the placenta, abnormal chromosomes, poor growth, and infections

  24. Dealing with Grief • Most couples feel a long sense of attachment prior to a baby’s birth • May go through similar stages of grief that a parent would to a child that was already born • Parents may blame themselves and feel alone • Couples may need support to deal with grief • Most couples that experience a miscarriage or stillbirth still have healthy children later

  25. Birth Defects • A serious problem that threatens a baby’s health, and is present at birth, is called a birth defect • Some are mild that no one would ever know the child has a birth defect • Others can result in disabilities or even death • Approximately 120,000 babies are born each year in the US with a birth defect • Scientists are still trying to identify some causes • If found, could possibly decrease the occurrence of birth defects

  26. Types and Causes of Birth Defects • Some defects cause an abnormality in the structure of the body • EX: extra or missing fingers/toes • Some defects cause one or more systems in the body to not function properly • EX: blindness, deafness, and mental retardation • Some abnormalities are not discovered until months or years after birth • 4 main causes of birth defects currently: • Environment • Hereditary • Errors in chromosomes • Combination of environment and hereditary factors

  27. Types and Causes of Birth Defects Environmental Hereditary Parents can pass off faulty recessive genes This is called recessive inheritance Tay-Sachs disease Cystic Fibrosis • Nutritional balance of the mothers diet • Any diseases or infection the mother has • Harmful substances; alcohol, over-the-counter medication, illegal drugs, etc. • Some medicines help the mother but hurt the baby • Air pollution • Exposure to X-Rays and high levels of radiation

  28. Types and Causes of Birth Defects Errors in Chromosomes Interactions of Heredity and Environment When an environmental and hereditary factors are present Examples Cleft lip Cleft palate Heredity and medications Spina bifida A predisposition, tendency, are combined medications during pregnancy • When a baby has too many or too few chromosomes • Most common birth defect is Down syndrome • 1 in 800 children are born with a form of Down syndrome • When you have too many or too few it can affect the body’s systems • Heart defects • Leukemia • Poor muscle tone • Physical growth or motor development

  29. Prevention and Diagnosis • Changing of your lifestyle • Frequent doctors visits for prenatal check-ups • Genetic counseling • Assesses their risk of having a child with a birth defect that is caused by a defect in genes • Compiling a family history • Prenatal Tests • More than 100 kinds of birth defects can be detected before birth

  30. Prenatal Tests Alpha-fetoprotein (AFP) Ultrasound Is a test that uses sound waves to make a video image of an unborn baby Can monitor problems with a baby’s skeletal, circulatory, or nervous system Usually during their 20th week Many doctors now do 3D ultrasounds • Blood test between 15 and 20 weeks • AFP is produced in the liver of the fetus and shows up in the mothers blood • Abnormal levels can indicate a possible birth defect

  31. Prenatal Tests Amniocentesis Chorionic Villi Sampling Uses a sample of tissue from the membrane that encases the fetus to check for birth defects Tissue is cut off and analyzed • The process of withdrawing a sample of the amniotic fluid surrounding the unborn baby • Often used as a test for Down syndrome with the mother is older than 35 years or older • Also may be completed if uncertain results are obtained from the AFP • Done between the 15th and 20th week

  32. Chapter 4 Section 3 Avoiding Dangers to the Baby

  33. Effects of Alcohol and Other Drugs on Pregnancy • Essential parts of good prenatal care is avoiding hazards such as • Alcohol • Drugs • Smoking • X-Rays • Hazardous chemicals • Other harmful substances • Infections • Environmental Factors

  34. Alcohol • Even small amounts can harm the baby • Doctors do not know the exact amount that can harm a baby • Avoid any amounts when trying to become pregnant Fetal Alcohol Syndrome • Incurable condition found in some children of mothers that consumed alcohol during pregnancy • 1 in 5 babies born with FAS do not live to 1 year old • Those that survive can have problems • Delayed physical growth • Heart, liver, kidney defects • Hyperactivity • Facial deformity • Mental retardation • Learning Disabilities

  35. Alcohol Fetal Alcohol Effects • Abnormalities caused by the mother consuming alcohol during pregnancy • Suffer less than children with FAS • Extent of damage is directly related to the amount the mother drinks • Binge drinking increases your risk of having a child with FAS

  36. Prescription Drugs and Over-The-Counter Drugs • Extreme example of unsafe mediation is thalidomide • 1950s- to relieve morning sickness • After proved harmful, 5,000 babies were born with birth defects • Missing or deformed arms, legs • Some acne medicine has been proven to cause problems • Chemicals found in some medications can cause mental retardation in the first 3 months • 4-9 months, OTC drugs can cause slow growth, infections, and bleeding at birth

  37. Caffeine • Passes easily through the placenta • Cause high blood levels of caffeine for fetus • Increases fetal heart rate and movement • Consumed in large amounts: • Miscarriage • Premature birth • Low birth weight • Can draw fluid and calcium out of the body • Small amounts (2 cups of coffee or soft drinks per day) not a huge risk

  38. Tobacco • Cause: • Low birth weight • Premature birth • Linked to: • Respiratory infections • Allergies

  39. Illegal Drugs • Mothers pass their addiction to their baby • After birth, babies must go through a painful period of withdrawal • Long-term effects can be learning and behavioral disabilities • Cocaine causes miscarriage, still birth, and premature births • Causes unborn child to have strokes resulting in brain and heart damage or even death • Low birth weight • Smaller heads • Risk of seizures • Risk of SIDS (sudden infant death syndrome) • Tremors • Exaggerated startle response • Irritability and developmental delays • Feeding and sleeping problems

  40. Illegal Drugs • Marijuana and methamphetamine use is liked to low birth weight and premature delivery • Breathing problems • Poor attention span • Drowsiness • Heart defects

  41. Environmental Hazards • Two possible hazards to unborn babies include X-rays and hazardous chemicals. • Radiation from X-rays, or from other sources, can cause birth defects • If an X-ray is necessary during pregnancy, inform your medical staff because precautions can be taken • Dental X-rays are generally considered safe

  42. Environmental Hazards • Hazardous Substances and Chemicals • Paint • Pesticides • Lead in water or paint • Carbon monoxide • Mercury found in some fish • Solvents, paint thinners, and formaldehyde

  43. Diseases and Infections Rubella Toxoplasmosis Caused by a parasite Most people have immune systems to fight it off Developing babies cannot Causes: Blindness Hearing loss Learning disabilities Severe cases Death Long-term learning disabilities Precautions: Never clean a cats litter box • Rubella is also called the German measles • Mother contracts it • Birth defects can happen within 1st three months • Blindness • Deafness • Heart disease • Mental retardation

  44. Diseases and Infections Chicken Pox Sexually Transmitted Infections Passed from mother to baby For Example: Syphilis can be treated if caught early to the unborn baby Can cause skin rash or lesions, bone/facial deformities, deafness, brain damage 2% end in miscarriage, stillbirth, or death • Viral infection • Depending when infection occurs during pregnancy will affect the outcome to the baby • 1st half of pregnancy • Congenital Varicella Syndrome • Causes scarring of the skin, limb defects, eye problems • Some cases miscarriage

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