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Chapter 12

Chapter 12. Conception, Pregnancy, and Childbirth. The Fertilization Process. Ovum released from ovary, drifts to fallopian tube Oocyte viable ~ 12 - 24 hours after ovulation Sperm viable ~ 12 - 48 hours Capacitation: takes 6-8 hours

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Chapter 12

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  1. Chapter 12 Conception, Pregnancy, and Childbirth

  2. The Fertilization Process • Ovum released from ovary, drifts to fallopian tube • Oocyte viable ~ 12 - 24 hours after ovulation • Sperm viable ~ 12 - 48 hours • Capacitation: takes 6-8 hours • biochemical changes in sperm cell; release enzymes that allows it to penetrate egg’s outer membranes

  3. Fertilization Process • A single sperm is inside the oocyte cytoplasm • An electrical reaction prevents any other sperm from entering • Oocyte swells • Detaches sperm that cling to outer layer • Sperm and ovum nuclei release chromosomes • Chromosomes divide to form the diploid zygote containing 23 pairs of chromosomes • Fertilization is now complete

  4. Development of the Conceptus • Zygote undergoes cell divisions • Becomes a blastocyst of 100 cells after 4-5 days • Blastocyst implants in uterine lining on 6th or 7th day • Blastocystbecomes embryo after implantation in uterus • Embryo is called a fetus after 8th week

  5. Pregnancy Detection • Test for human chorionic gonadotropin (HCG) • Blood analysis • Home pregnancy tests • Early physical signs • Changes in cervix occur about 4 weeks after a missed period • Hegar’s sign • Labia change color, gaining purple hue

  6. Changes in Women During Pregnancy • Vary according to woman’s personality, feelings, and circumstances • Changes in relationships • Physical and emotional changes during each trimester • Three trimesters—each 3 months long • First trimester may include nausea, vomiting, fatigue

  7. Complications of Pregnancy and Dangers to the Fetus • Effects of teratogens • Substances that cause defects in embryonic and fetal development • Infectious diseases • German Measles (rubella) • Group B streptococcus

  8. Sexually transmitted infections Can be transmitted from pregnant woman to fetus, newborn, or infant Chlamydia Gonorrhea Hepatitis B HIV Syphilis Genital herpes Complications of Pregnancy and Dangers to the Fetus

  9. Complications of Pregnancy and Dangers to the Fetus • Pregnancy after age 35 • Is more common as women wait to have children • Increased likelihood of chromosomal variation • Risk increases with increasing maternal age

  10. Complications in Pregnancy • Ectopic pregnancy • Pregnancy-induced hypertension • Premature births • Delayed labor

  11. Diagnosing Abnormalities of the Fetus • Ultrasound • Amniocentesis • Chorionic villus sampling (CVS) • Alpha-fetoprotein (AFP) screening

  12. Ultrasound • High frequency sound waves determine size and position of fetus • Sonogram—picture • Estimates fetal age, guides during amniocentesis, checks for physical birth defects, evaluates complications during pregnancy

  13. Amniocentesis • Amniotic fluid is withdrawn with needle inserted through abdominal wall • Detects: fetal abnormalities; Down’s syndrome, Turner’s syndrome, cystic fibrosis, spina bifida, sex and age • 0.5-2% chance of fetal death

  14. Chorionic Villus Sampling (CVS) • Thin catheter inserted through abdomen or cervix into uterus and some chorionic villi are sucked into tube • Detects: fetal abnormalities • Performed 9-11 weeks

  15. Alpha-fetoprotein Screening • Test run on mother’s blood • After 16 weeks of pregnancy • Detects: defects of spine, spinal cord, skull and brain

  16. Pregnancy Loss • Early pregnancy loss • Miscarriage • Infant mortality • Coping with loss

  17. Infertility • The inability to conceive a child after a year of unprotected intercourse or the inability to carry a child to term • Fertility issues are equally distributed among men and women • 1% of children in U.S. are the product of assisted fertility

  18. Female Infertility • Physical causes • Pelvic Inflammatory Disease, an infection of the fallopian tubes or uterus • Approximately 20% • Hormonal & psychological causes • Hormone release may be atypical • Stress, anxiety, allergy • Approximately 20% • Environmental factors

  19. Male Infertility • Low sperm count • Decrease of sperm motility • Misshapen sperm • Sperm duct blockage • Ejaculatory difficulties • Environmental factors • Men’s fertility begins dwindling after age 27

  20. Infertility Treatment • Enhancing fertility • Selective timing of sexual activity • Man wears boxer underwear • Woman lies with her back elevated following internal ejaculation

  21. Medical Intervention • Fertility medications • Surgery • Artificial insemination

  22. Assisted Reproductive Technology • In vitro fertilization - IVF • Gamete intrafallopian transfer – GIFT • Zygote intrafallopian transfer – ZIFT • Surrogate motherhood • Cloning • Sex selection

  23. Giving Birth: Labor and Delivery • Relaxin released by the placenta • Braxton Hick contractions

  24. Labor Stages • Stage 1: • Effacement: thinning of cervix • Dilation: opening up of cervix • Mucus plug is expelled • Amniotic sac ruptures • Contractions are regular and progressive • Transition

  25. Labor and Delivery • Stage 2 • Begins when baby’s head moves into birth canal • Ends when baby is born • Vernix: waxy substance which may cover baby • Stage 3 • Afterbirth: placenta is expelled

  26. Following birth • Neonate • Apgar score • Lochia • Joy

  27. Choices in Childbirth • Hospital birth • Cesarean section • Prepared childbirth • Episiotomy • Birthing rooms and centers • Home birth • Midwifery

  28. Breast Feeding • Colostrum • Benefits • Bonding • Immune system of baby • HIV

  29. Becoming a Parent • Postpartum period • Postpartum depression • Postpartum psychosis • Family Medical Leave Act

  30. Summary • Fertilization and fetal development • Being pregnant • Infertility • Giving birth • Becoming a parent

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