Lecture Notes, Biology 203

Lecture Notes, Biology 203, Human Sexuality and Reproduction

Assisted Reproductive Technologies

Assisted Reproductive Technologies
1. Artificial insemination (not new, done since 1866)
  1. Can be done with husband's normal sperm, or husband's sperm enhanced for fertility or with donor sperm
  2. Insertions of sperm through cervix into woman's uterus near time of ovulation
  3. Sperm are expected to swim up Fallopian tubes to meet woman's egg after ovulation
2. In vitro fertilization
  1. First successful in 1978
  2. Egg and sperm combined outside bodies; after fertilization and first few cell divisions, zygote returned to woman's body
  3. Results in pregnancy 15% to 25% of the time, depending on the laboratory
  4. Procedure
    1. In first two weeks of menstrual cycle: meaure urine estrogen daily
    2. At midpoint of cycle: measure urine LH every 3 hours, looking for beginning of 7X rise in LH levels
    3. Ovulation should occur 22 hours after beginning of rise in LH
    4. 1-4 hours before ovulation is anticipated: collect ovum from intact follicle just before rupture
    5. Transfer follicle to culture dish
    6. Male collects sperm (in semen)--they are transferred to culture dish, where they sit for 2-3 hours for capacitation to occur
    7. Combine ovum with sperm; wait 2-3 hours for fertilization to occur
    8. First cell division should occur in about 12 hours
    9. Transfer zygote to dish with more nutritious culture fluid
    10. After 50 hours postfertilization, zygote should have reached 8-cell stage
    11. Transfer into woman's uterus (she has been given HCG to maintain luteal function and progesterone to maintain uterine lining in secretory phase
    12. Implantation should occur soon after (woman continues to get HCG)
  5. Woman needs functioning uterus, and usually ovary, but not Fallopian tubes
3. Gamete intrafallopian transfer (GIFT)
  1. Egg and sperm are transferred into Fallopian tube
  2. Fertilization takes place in Fallopian tube
  3. Requires healthy Fallopian tube, at least partially, as well as uterus and ovary (usually)
4. Zygote intrafallopian transfer (ZIFT)
  1. Egg and sperm are combined outside body to confirm that fertilization has taken place
  2. Zygote inserted into Fallopian tube
  3. Requires at least one healthy Fallopian tube, ovary (usually), uterus
5. Intracytoplasmic sperm injection (ICSI)
  1. Used if make has low number of normal viable sperm
  2. Requires only one healthy sperm
  3. Sperm doesn't have to swim, or survive in female reproductive tract, or penetrate zona pellucida
  4. Sperm is injected into egg cytoplasm through the zona pellucida
6. Assisted hatching
  1. Create hole in zona pellucida around fertilized egg
  2. Leads to increased chance of implantation
7. Success rates (per attempt, data from 1999, based on 71,826 ART's, age 30-39)
  1. Natural unassisted fertilization: about 25% (early 20's, no fertility problems)
  2. ART overall: 27% (live births per egg retrieved)
  3. IVF: 27.7% live births/egg retrieval
  4. GIFT: 29.8%
  5. ZIFT: 28%
  6. ICSI: 29%
  7. Blastocyst transfer (5 day): 25-40%
  8. Success rates using donor eggs in any of these (ex. ICSI) depends on age of donor--if donor <35, about 30%
8. Relevant statistics
  1. Source of fertility problem is in female 50% of the time, in male 50% (range 40-60%)
  2. About 10% of couples of reproductive age have some fertility problem
  3. About 25% of couples who have a problem have more than one problem
  4. About 35% of infertility in women is due to tubal blockage
  5. About 50% of infertility in women is due to ovulation problem
  6. About 35% of intertility problems in women involve endometriosis (growth of endometrial cells in abdominal cavity, leading to scarring)
  7. About 70,000 babies per year are born using assisted reproduction techniques; of those 45,000 used IVF