1. Fertility
Noadswood Science, 2016

2. Friday, June 15, 2018
Fertility
To know how hormones are used in the body, and how these control the menstrual cycle

3. Precise Learning
Students should be able to evaluate the different hormonal and non-hormonal methods of contraception.
Fertility can be controlled by a variety of hormonal and non- hormonal methods of contraception. These include:
oral contraceptives that contain hormones to inhibit FSH production so that no eggs mature
injection, implant or skin patch of slow release progesterone to inhibit the maturation and release of eggs for a number of months or years
barrier methods such as condoms and diaphragms which prevent the sperm reaching an egg
intrauterine devices which prevent the implantation of an embryo or release a hormone
spermicidal agents which kill or disable sperm
abstaining from intercourse when an egg may be in the oviduct
surgical methods of male and female sterilisation.
Students should be able to explain the use of hormones in modern reproductive technologies to treat infertility (higher tier only)
This includes giving FSH and LH in a 'fertility drug' to a woman. She may then become pregnant in the normal way (higher tier only)
In Vitro Fertilisation (IVF) treatment:
IVF involves giving a mother FSH and LH to stimulate the maturation of several eggs (higher tier only)
The eggs are collected from the mother and fertilised by sperm from the father in the laboratory (higher tier only)
The fertilised eggs develop into embryos (higher tier only)
At the stage when they are tiny balls of cells, one or two embryos are inserted into the mother's uterus (womb) (higher tier only)
Although fertility treatment gives a woman the chance to have a baby of her own:
it is very emotionally and physically stressful (higher tier only)
the success rates are not high (higher tier only)

4. Reducing Fertility
Contraceptives are used to prevent pregnancy – the hormones oestrogen and progesterone are used…
Oestrogen prevents egg release as it inhibits FSH so egg maturation will not occur
Progesterone stimulates thick cervical muscle preventing sperm getting through

5. Oral Contraceptives The pill is an oral contraceptive
Benefits > 99% effective and also reduces the risk of getting some types of cancer
Problems > not 100% effective; can cause side effects such as headaches, nausea, irregular menstrual bleeding and fluid retention; doesn’t protect against STDs

6. Patches, Implants and Injections
The contraceptive patch contains oestrogen and progesterone and lasts a week (stuck to the skin)
Implants are inserted under the skin of the arm and releases continuous amounts of progesterone (lasting up to three years)
Contraceptive injection contains progesterone and lasts for 2-3 months

7. Barrier Methods
Barrier methods are designed to stop the sperm from getting to the egg
Condoms have the benefit of protecting against STDs
Diaphragms are shallow cups that fit over the cervix forming a barrier (they also contain a spermicide)

8. Intrauterine Devices
An intrauterine device (IUD) is a T-shaped device inserted into the uterus to kill sperm and prevent implantation of a fertilised egg (either plastic or copper)

9. Surgical Methods
Sterilisation involves cutting or tying the fallopian tubes in a female or the sperm duct in a male – this is a permanent procedure (however there is a very small chance that the tubes can rejoin)

10. Abstaining
Pregnancy may be avoided by finding out when in the menstrual cycle the woman is most fertile and avoiding sexual intercourse on those days – however it is not a very effective methods
The only way to be completely sure that sperm and egg do not meet is by not having intercourse (abstinence)

11. Increasing Fertility
Some women have difficulty becoming pregnant because they don't produce enough FSH to allow their eggs to mature – ‘fertility drugs' contain FSH, which stimulates eggs to mature in the ovary
Fertility treatments increase a woman's chance of becoming pregnant, although the treatment may not always work
On the other hand, because the treatment boosts the production of mature eggs, multiple conceptions sometimes occur, with twins or triplets being expected, increasing the risk of complications in pregnancy and childbirth
Higher Tier

12. IVF
If a couple are having difficulty conceiving a child because the quantity or quality of the man’s sperm is poor then in vitro fertilisation (IVF) can be used
This is where the egg is fertilised outside the woman’s body and then implanted back into her uterus
As FSH can also be used to encourage the production of several mature eggs at once, it is used as part of IVF to increase the number of eggs available for fertilisation
Higher Tier

13. IVF
Higher Tier

14. Practice Questions Give an example of a barrier contraceptive
Why is a mother given FSH and LH as the first stage of IVF treatment?
Give two downsides of IVF
Why might a person believe IVF is unethical?

15. Answers
Give an example of a barrier contraceptive – condom / diaphragm
Why is a mother given FSH and LH as the first stage of IVF treatment – to stimulate the maturation of eggs
Give two downsides of IVF – multiple births / success rate is low / emotionally and physically stressful
Why might a person believe IVF is unethical – results in unused embryos which are potentially human lives being destroyed