Conception, Pregnancy, and Childbirth

1. 12 Conception, Pregnancy, and Childbirth

2. A Matter of Choice • Parenthood is now a matter of choice • Increasing numbers of individuals and couples are choosing to remain child-free • The birth of a wanted child is generally considered joyful • Some emotional pain and controversy for others • Drugs, disease, malnutrition, familial chaos • Infertility

3. Fertilization Process • Ovum released from ovary, drifts to fallopian tube • Oocyte viable ~ 12 - 24 hours after ovulation • Sperm viable ~ 12 - 48 hours • May be fertilized there if live sperm are present • If pregnancy proceeds normally, birth 266 days later • Capacitation: takes 6-8 hours • biochemical changes in sperm cell; release enzymes that allows it to penetrate egg’s outer membranes

4. 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

5. 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

6. Development of the Conceptus

7. Pregnancy Tests • Test for human chorionic gonadotropin (HCG) • A chemical secreted by the developing placenta • Blood analysis • Home pregnancy tests • Early physical signs • Changes in cervix occur about 4 weeks after a missed period • Hegar’s sign • A softening of the uterus just above the cervix • Labia change color, gaining purple hue

8. Changes That Occur During Pregnancy • Vary according to woman’s personality, feelings, and circumstances • Changes in relationships • Physical and emotional changes during each trimester • Three trimesters - each three months long • First trimester may include nausea, vomiting, fatigue

9. Complications of Pregnancy • Effects of teratogens • Substances that cause defects in embryonic and fetal development • Toxins ingested by mother affect fetus • Infectious diseases • German Measles (rubella) • Group B streptococcus

10. Complications of Pregnancy • Sexually transmitted diseases • Can be transmitted from pregnant woman to fetus, newborn, or infant • Chlamydia • Gonorrhea • Hepatitis B • HIV • Syphilis • Genital herpes

11. Complications in Pregnancy • Some complications: • Ectopic pregnancy • Pregnancy-induced hypertension • Premature births • Operative delivery (Caesarian Section) • Women age 40+ are more likely to experience complications in pregnancy

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

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

14. 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 & age • 0.5-2% chance of fetal death

15. 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

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

17. Infertility • Infertility: • the inability to conceive a child after a year of unprotected intercourse or the inability to carry a child to term • Causes for women: • Pelvic Inflammatory Disease, an infection of the fallopian tubes or uterus • Usually the result of an STI • Hormonal & psychological causes • Glands might not release hormones to stimulate ovulation • Stress may contribute to lowered fertility • A woman might be allergic to her partner’s sperm

18. Infertility: • Physical causes for women, continued: • Environmental factors • Toxic chemicals, exposure to radiation therapy • Natural factors • Beginning around age 30, women’s fertility naturally begins to decline • ¼ of women are infertile by age 35

19. Infertility • Causes for men: • Low sperm count • Sperm motility decrease • Misshapen sperm • Sperm duct blockage • Ejaculatory difficulties • Environmental factors • Natural factors • Men’s fertility begins dwindling after age 27

20. Enhancing Fertility • Some simple, non-medical techniques • Examples: • Man stops wearing tight underwear • Woman lies on her back for an hour after coitus

21. Medical Intervention • Treatment successful in at least 50% of cases • Fertility medications • Surgery • Procedures • Intrauterine insemination (IUI) • Assisted reproductive technology • In vitro fertilization (IVF) • Micromanipulation technique • Third-party methods • Includes egg donation, sperm donation, and surrogate motherhood

22. Labor and Delivery • 3 stages • Stage 1: • Effacement: thinning of cervix • Dilation: opening up of cervix • mucus plug is expelled • amniotic sac ruptures • contractions are regular & progressive

23. Labor and Delivery • Stage 2 • Begins when baby’s head moves into birth canal • Ends when baby is born • Stage 3 • Placenta is expelled

24. Choices in Childbirth • Hospital birth • Cesarean section • Prepared childbirth • Birthing rooms & centers • Home birth • Midwifery • Breast-feeding