Fertilization, Pregnancy, and Labor and Delivery

1. Fertilization, Pregnancy, and Labor and Delivery Ch. 29

2. Pregnancy by Weeks • Doctors and midwives track pregnancy by weeks. • A typical pregnancy and full-term is 40 weeks • The weeks are counted from the first day of your last period • This means that during week 1, you are not technically pregnant yet

3. Embryonic Period • Fertilization (week 2) • Sperm and egg unite • 300 million sperm make it into the vagina • Only 2 million reach the cervix • Only 200 reach the egg in the fallopian tube • Fertilization occurs 12-24 after ovulation • Pregnancy is most likely during a 3-day window • 2 days before ovulation to 1 day after ovulation

4. Fertilization • Videos

5. After Fertilization • Cell is called a zygote • Cleavage • Mitotic divisions of cells • 1 to 2 to 4 to 16 (3 days) • Implantation • Zygote implants into wall of uterus • Occurs 6 days after fertilization

6. After Fertilization

7. Twins • Twins • Dizygotic (fraternal) – two sperms, two eggs • Monozygotic (identical) – 1 egg, 1 sperm, divides within first 8 days • After 8 day division – conjoined twins • Ectopic Pregnancy • Development of embryo outside uterus • Can happen in fallopian tube or ovary • Pregnancy cannot continue

8. Summary of second week

9. Review • What occurs in the first 3 days after fertilization? • Describe the difference between fraternal and maternal twins. • What occurs during the first week after fertilization?

10. By the end of month 1 • Baby is ¼ inch long, size of poppy seed • Heart, digestive system, backbone, and spinal cord are beginning to form • Placenta develops

11. By the end of month 2 • Heart is functioning • Eyes, nose, lips, tongue, ears, teeth are forming • Baby is moving, but mom can’t feel it yet • Arm and leg buds appear • Size of a kidney bean • http://www.babycenter.com/2_inside-pregnancy-weeks-1-to-9_10302602.bc

12. By the end of month 3 • Arms, hands, fingers, legs, and toes are fully formed • Nails form, hair grows • Most organs are fully formed • Reflexes – opening mouth, sucking, grasping • Urinating – drinks urine • Size of a lime

13. By the end of month 4 • Genitals are developed • Skin is pink and covered in soft hair • Can suck thumb • Facial expressions • “breathing” – moves amniotic fluid into lungs • Taste buds form, eyes can sense light but are still closed • Size of avocado • http://www.babycenter.com/2_inside-pregnancy-weeks-1-to-9_10302602.bc

14. By the end of month 5 (1/2 way) • Baby weighs 1 lb. (size of banana) • Mommy can feel baby move • Internal organs mature • Eyebrows, eyelids, eyelashes appear • Cartilage is turning to bone • Nerves are becoming myelinated • Baby can hear voices or loud noises • Produces meconium • http://www.babycenter.com/2_inside-pregnancy-weeks-1-to-9_10302602.bc

15. By the end of the 6th month • Eyes can open • Skin is covered in waxy vernix to prevent pickling in amniotic fluid • Baby hiccups – mom can feel it • Mom can see baby move in belly • Baby is gaining weight

16. By the end of the 7th month • If baby is born now, he could survive but need special care • Hair is growing • Baby is gaining fat • Baby sleeps and is awake • Baby can blink and see light • http://www.babycenter.com/2_inside-pregnancy-weeks-21-to-27_10312242.bc

17. By the end of the 8th month • Brain grows • Weight gain is rapid • Organs are fully developed except lungs • Skin is less wrinkly, baby is filled out

18. By the end of the 9th month • Baby has turned head down to prepare for birth • Lungs are fully developed • http://www.babycenter.com/2_inside-pregnancy-weeks-21-to-27_10312242.bc

19. Review • Summarize the events that take place in each month of pregnancy. Focus mainly on organ development.

20. Prenatal Testing • Doppler – used to listen to baby’s heartbeat • Ultrasound – used to get accurate fetal age, check for proper growth, determine fetal position, identify multiple pregnancies Ultra sounds pics here!

21. Amniocentesis • Invovles withdrawing some amniotic fluid and analyzing fetal cells • Can detect genetic disorders • Down syndrome • Hemophilia • Tay-Sach’s disease • Sickle-cell disease • Ultrasound is used to prepare • Needle is inserted through mother’s abdomen and into amniotic cavity • Fluid is withdrawn and analzyed

22. Chorionic Villi Sampling (CVS) • Catheter is guided through vagina and cervix into chorionic villi of placenta • Can detect same disorders as amniocentesis • Advantages • Can be done earlier • Test results are quicker • Abdominal penetration isn’t required • Disadvantage – increased risk for miscarriage (1-2%)

23. Early Pregnancy Test (EPT) • Detect tiny amounts of human chorionic gonadotropin (hCG) in urine • False-positives are rare – if you have the hormone, you are pregnant • False-negatives are more common – testing too soon

24. Labor • Contractions can begin weeks before delivery • Sometimes the mother can’t feel them • Braxton-Hick’s contractions – tightening of the muscles surrounding the baby, but not uterine • Induced by oxytocin • “false” labor – when contractions are irregular, no dilation, no mucus discharge (plug) • “true” labor – mucus plug, contractions are regular, walking intensifies contractions

25. Labor • 3 stages • Stage of dilation (6-12) hours • Starts from start of labor to complete dilation (10 cm) • Amniotic sac breaks (water) • Stage of expulsion (10 min. to several hours) • From complete dilation to delivery of baby • Placental stage (5-30 min.) • When placenta is delivered

26. Labor

27. C-Section • Cut through abdominal wall and lower uterus • Baby is removed • Stitches to close up incision • Done because: • Woman is not progressing • Baby is not in correct position • Mother’s body could not handle delivery (blood pressure, etc.)

28. Newborn • Often have cone-shaped heads because of trip through birth canal • Suction is used to clear nose and mouth for breathing

29. Videos • http://www.babycenter.com/2_inside-pregnancy-weeks-21-to-27_10312242.bc