1. c The biology of controlling fertility
What do you know?
What methods are there of controlling fertility naturally?
What methods are there of treating infertility?
What methods are there of contraception?
How do all these work?
Contraception and the treatment of infertility are based on the biology of fertility.
There are some risks and ethics associated with fertility treatments.

2. Fertility Men are continuously fertile
Negative feedback involving the effect of testosterone on FSH and ICSH (pituitary gland)
Sperm are always being produced
Women have cyclical fertility
Fertile for about 1-2 days following ovulation
Caused by ovarian and pituitary gland hormone interaction

3. Natural fertile period for women
Temperature rise of about 0.5oC after ovulation
Caused by progesterone production
Fertile for 1-2 days before egg disintegrates
Mucus of cervix also thinner at this time

4. Infertility
This can be caused by: male sterility low sperm count defective sperm blockage of oviducts failure to ovulate (no FSH or LH)

5. Artificial Insemination
Semen is collected and frozen
Unfrozen and released together as a large sample at fertile period in uterus
A donor can be used for this process if male is sterile

6. Stimulating ovulation
Drugs to mimic action of FSH and LH
Drugs to prevent oestrogens negative feedback on FSH secretion during luteal phase
More eggs are matured
This can lead to multiple pregnancy/births
(These drugs are used in IVF also)

7. In-vitro fertilisation (IVF)
Overcomes blocked oviducts
Eggs are fertilised outside the body
Process
Drugs to produce more eggs given
Eggs harvested
Eggs mixed with semen in petri dish with nutrients
(or sperm can be injected directly into the egg)
Fertilised eggs incubated for 2-3 days (division 8 or more cells)
2 or 3 embryos inserted into uterus through the vagina
Unused embryos frozen for later use

8. Testing of genetics before implantation
In IVF cells can be taken for genetic screening and diagnosis
Pre-implantation genetic screening (PGS)
Non specific checking of embryo fro single gene disorders and common chromosomal abnormalities
Pre-implantation genetic diagnosis (PGD)
Specific checks for known chromosomal or gene defects
Ethics of this type of testing?
Reassurance/benefit OR designer babies/eugenics

9. Improving chances of fertilisation in IVF
Eggs mixed with semen OR
Sperm injected directly into the egg called
Intra cytoplasmic sperm injection (ICSI)
This can overcome problem
defective sperm or
low sperm count

10. Contraception
Methods both natural and artificial to prevent conception or pregnancy
Barriers
Condoms
Diaphragm
Cervical cap
Femidom
Intrauterine devices (IUDs)
T shaped structure (plastic/metal) fitted into uterus prevents implantation by irritation

11. Chemicals Oral contraceptive pill Synthetic progesterone and oestrogen
1 per day for 3 weeks
Mimic negative feedback of FSH and LH so no ovulation
Morning after pill
High levels of progesterone and oestrogen prevent implantation of fertilised egg
Mini pill
Progesterone only pill
Thickens the cervical mucus, reducing sperm viability and uterus access

12. Sterilisation
Vasectomy (men) sperm ducts cut and tied Tubal ligation (women) cutting and tying of oviducts Both effective but normally irreversible.

13. c The biology of controlling fertility
What do you know now?
What methods are there of controlling fertility naturally?
What methods are there of treating infertility?
What methods are there of contraception?
How do all these work?
Consolidate by reading chapter and completing questions, making own notes, completing scholar, multiple choice questions.