© 2009 Allyn & Bacon Publishers Prenatal Development And Birth 3 This multimedia product and its contents are protected under copyright law. The following are prohibited by law: any public performance or display, including transmission of any image over a network; preparation of any derivative work, including the extraction, in whole or part, of any images; any rental, lease, or lending of the program.

© 2009 Allyn & Bacon Publishers The Process of Conception –Ovum –Sperm The Journey of Sperm toward Ovum Chromosomes –DNA –Genes –X and Y chromosomes Conception and Genetics

© 2009 Allyn & Bacon Publishers Twins –Identical –Fraternal –Semi-identical (different genes from father) Twins in genetic research Increases in multiple births Conception and Genetics

© 2009 Allyn & Bacon Publishers Genotype — the genetic blueprint Phenotype — observable characteristics Dominant–recessive pattern –Dominant genes always express their characteristics –Recessive genes come in pairs to express their characteristics Polygenic Inheritance –Many genes blend together to increase genetic outcomes seen in the phenotype Conception and Genetics

© 2009 Allyn & Bacon Publishers Figure 3.1 The Genetics of Hair Type

© 2009 Allyn & Bacon Publishers Genomic Imprinting –Some genes biochemically marked at the time ova and sperm develop Mitochondrial Inheritance –Genes in the mitochondria, fluid surrounding the nucleus of the ovum Conception and Genetics

© 2009 Allyn & Bacon Publishers Genetics and the environment –Differ in their reactivity –Two-way interplay –Ecological framework People actively process their experiences People shape and select their experiences Conception and Genetics Multi-Factorial Inheritance

© 2009 Allyn & Bacon Publishers Non-sex-lined genes Disorders caused by recessive genes –Phenylketonuria (PKU) –Sickle-cell disease –Tay-Sachs disease Disorders caused by dominant genes –Huntington’s disease Genetic Disorders Autosomal Disorders

© 2009 Allyn & Bacon Publishers Red–green colorblindness Hemophilia Fragile-X syndrome Caused by recessive gene on X chromosome Boys suffer more often than girls Genetic Disorders Sex-linked Disorders

© 2009 Allyn & Bacon Publishers Figure 3.2 Sex-linked Inheritance

© 2009 Allyn & Bacon Publishers Chromosomal Errors –Too many or too few chromosomes Trisomy 21 — Down Syndrome Mental retardation Distinctive facial features Physical abnormalities Maternal age is a major factor Chromosomal Errors Trisomies

© 2009 Allyn & Bacon Publishers XXY — Klinefelter’s syndrome XO — Turner’s syndrome XXX — girls with an extra X XYY — boys with an extra Y Chromosomal Errors Sex Chromosome Anomalies

© 2009 Allyn & Bacon Publishers The zygote implants in the uterus The cervix Prenatal care critical at this time Ectopic pregnancy in fallopian tube rather than uterus –Threatens life and future fertility Pregnancy and Prenatal Development The Mother’s Experience: First Trimester

© 2009 Allyn & Bacon Publishers Fetus grows rapidly Sex can be determined after week 13 Fetal movement felt between week 16 and 18 Prenatal care may detect gestational diabetes Risk of miscarriage drops Pregnancy and Prenatal Development The Mother’s Experience: Second Trimester

© 2009 Allyn & Bacon Publishers Colostrum in preparation for nursing Emotional connection between mother and baby grows Fetal hiccups and thumb sucking visible on sonogram Fetus has regular periods activity and rest Toxemia –Sudden high blood pressure Pregnancy and Prenatal Development The Mother’s Experience: Third Trimester

© 2009 Allyn & Bacon Publishers From conception to implantation Blastocyst implants Specialization of cells needed to support development –Placenta –Umbilical cord –Yolk sac –Amnion 3 Stages of Prenatal Development The Germinal Stage: The Zygote

© 2009 Allyn & Bacon Publishers Forms the foundations of all body organs Neural tube develops All major organs and systems begin to develop Many organs and systems begin to function 3 Stages of Prenatal Development The Embryonic Stage

© 2009 Allyn & Bacon Publishers Growth from 1/4 ounce and 1 inch to 7 pounds and 20 inches in length Refinement of all organ systems Neuronal proliferation Age of viability—week 24 Full term status—week 37 onward 3 Stages of Prenatal Development The Fetal Stage

© 2009 Allyn & Bacon Publishers Figure 3.3 Parts of the Neuron

© 2009 Allyn & Bacon Publishers Males are: –More physically active –Higher rates of miscarriage –More vulnerable to prenatal problems Females are: –More sensitive to external stimulation –More rapid skeletal development Prenatal Sex Differences

© 2009 Allyn & Bacon Publishers Fetuses can differentiate between familiar and novel stimuli Newborns can remember prenatal stimuli and react accordingly Very active fetuses tend to be active children who can be labeled “hyperactive” later on Prenatal Behavior

© 2009 Allyn & Bacon Publishers Figure 3.6 Correlations between Fetal Behavior and Brain Development

© 2009 Allyn & Bacon Publishers Questions to Ponder You are told by a genetic counselor that you have 25% chance of passing on a deadly genetic trait to your child. Do you still have a child? What factors influence your choice? How do we curtail the use of teratogens, such as smoking and alcohol use, by pregnant women?

© 2009 Allyn & Bacon Publishers Substances that can damage an embryo Each organ system most vulnerable to harm when its development is most rapid (Figure 3.7) The first 8 weeks the most dangerous Duration and intensity of teratogen exposure important Problems in Prenatal Development Teratogens

© 2009 Allyn & Bacon Publishers Figure 3.7 Timing of Teratogen Exposure

© 2009 Allyn & Bacon Publishers Prescription Over the Counter Marijuana and Heroin Cocaine Smoking Alcohol use –Fetal Alcohol Syndrome Problems in Prenatal Development Teratogens: Drugs

© 2009 Allyn & Bacon Publishers Rubella (“German measles”) HIV Other sexually transmitted diseases –Syphilis –Genital herpes –Gonorrhea –Cytomegalovirus Problems in Prenatal Development Teratogens: Maternal Diseases

© 2009 Allyn & Bacon Publishers Diet –Folic acid deficiencies –Malnutrition Low birth weight Brain stunting –Reduced weight and volume of the brain Fetal death Problems in Prenatal Development Other Maternal Influences

© 2009 Allyn & Bacon Publishers Age –First pregnancies are occurring later—average age is now 25.1 years –Women over 35 have higher risks for pregnancy complications –Teenage mothers May suffer from poverty and poor prenatal care Children may exhibit learning and behavior problems in school Problems in Prenatal Development Other Maternal Influences

© 2009 Allyn & Bacon Publishers Chronic Illnesses –Depression can slow fetal growth –Epilepsy –Diabetes Most medical conditions must be monitored to support health of the mother and developing fetus Problems in Prenatal Development Other Maternal Influences

© 2009 Allyn & Bacon Publishers Limiting exposure to mercury Avoiding possible harmful chemicals –Lead –Arsenic –Anesthetic gasses –Solvents –Parasite-bearing substances Problems in Prenatal Development Environmental Hazards

© 2009 Allyn & Bacon Publishers Stress –Can change hormone levels Mixed information from research Severely distressed mothers produce fetuses who grow slowly Social support and counseling may help. Problems in Prenatal Development Maternal Emotions

© 2009 Allyn & Bacon Publishers Ultrasonography Chorionic Villus Sampling Amniocentesis Alpha-fetoprotein test Fetoscopy Fetal Assessment and Treatment

© 2009 Allyn & Bacon Publishers Figure 3.8 Two Methods of Prenatal Diagnosis

© 2009 Allyn & Bacon Publishers Location of Birth –Home versus hospital –Birthing rooms Birth Attendants –Certified nurse-midwives Drugs during Labor and Delivery “Natural childbirth” –Lamaze Method Birth Choices

© 2009 Allyn & Bacon Publishers Stage 1 –Contractions –Dilation of the cervix Stage 2 –Actual delivery of the baby Stage 3 –Delivery of the placenta and umbilical cord The Physical Process of Birth Labor

© 2009 Allyn & Bacon Publishers Figure 3.9 The Three Stages of Labor

© 2009 Allyn & Bacon Publishers

Cesarean Deliveries –Fetal Distress –Breech presentation –Birth size –Poor progress during labor –Health and age concerns The Physical Process of Birth Birth Complications

© 2009 Allyn & Bacon Publishers Figure 3.10 Duration of Labor in First and Second Births

© 2009 Allyn & Bacon Publishers First month of life Apgar Scale –Table 3.7 Brazelton Neonatal Behavioral Assessment –Tracks development over 2 weeks –Responses to stimuli and reflexes are checked The Physical Process of Birth Assessing the Neonate

© 2009 Allyn & Bacon Publishers LBW – below 2,500 grams (5.5 pounds) Preterm – mostly born before week 38 Small-for-date neonates Respiratory distress syndrome Adequate parental education and support reduces risk of complications Low Birth Weight Babies (LBW)