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Biology · The Endocrine System

Contraception and Fertility Treatment

Hormones can be used to prevent pregnancy and to help people who cannot conceive. This lesson covers hormonal and non-hormonal contraception and how to evaluate them, and for Higher tier students how hormones are used in fertility treatments such as IVF.

  • 8 key terms
  • All boards

Learning Objectives

  1. 1Explain the use of hormones in contraception.
  2. 2Evaluate hormonal and non-hormonal methods of contraception, using data on their relative effectiveness.
  3. 3(Higher tier) Explain the use of hormones in modern reproductive technologies to treat infertility.
  4. 4(Higher tier) Describe the stages of IVF and evaluate its advantages and disadvantages.

Retrieval practice

  1. 1

    What does FSH do?

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    Makes an egg mature in an ovary.

  2. 2

    What causes ovulation?

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    A surge of LH.

  3. 3

    What does progesterone do?

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    Maintains the lining of the uterus.

  4. 4

    What does oestrogen do to FSH release?

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    A high level stops it.

Choosing whether to have a child

Contraception lets people choose when, or whether, to have children. Some methods stop an egg being released, some stop sperm reaching it, and some stop an embryo from implanting. Hormones can also help in the opposite situation, when a couple find it difficult to conceive. Understanding how the hormones of the menstrual cycle work makes it possible to control fertility in both directions.

Hormonal methods of contraception

Hormonal methods use hormones to change the menstrual cycle so that pregnancy is unlikely.

  • The combined pill

    Contains oestrogen and progesterone. These keep the level of the hormones high, so the pituitary gland does not release FSH and no egg matures. It is taken daily.

  • The progesterone-only pill, injection and implant

    Progesterone thickens the mucus at the cervix, so sperm cannot pass, and can stop the release of an egg. The injection and the implant release hormone slowly, for weeks to years.

  • The patch

    A patch on the skin releases hormones into the blood.

  • Effect

    When used correctly these methods are very effective, but they do not protect against sexually transmitted infections.

Non-hormonal methods of contraception

Other methods do not use hormones.

  • Condoms

    A barrier that stops sperm entering the vagina. Condoms also protect against sexually transmitted infections.

  • Diaphragm

    A rubber cap placed over the cervix with spermicide, which kills sperm.

  • Intrauterine device (IUD)

    A small device placed in the uterus. A copper IUD kills sperm and stops an embryo implanting.

  • Abstaining

    Not having sex at the times when an egg may be in the oviduct.

  • Sterilisation

    An operation to cut or tie the oviducts in women, or the sperm ducts in men. It is permanent.

Hormonal and non-hormonal contraception

Hormonal methods

  • Very effective when used correctly
  • Pill: taken daily, so easy to forget
  • Implant and injection last for weeks or years
  • Do not protect against infections
  • Can have side effects such as headaches or mood changes

Non-hormonal methods

  • Condoms protect against infections
  • No effect on the hormones
  • Barrier methods are less effective if used wrongly
  • IUD lasts for years
  • Sterilisation is permanent

Evaluating contraception

To evaluate a method you need to compare how well it works with its other advantages and disadvantages.

  • Effectiveness

    Use the data. The lower the number of pregnancies per 100 women, the more effective the method.

  • Use

    A method that depends on remembering, such as a daily pill, is less effective in real use than one that does not, such as an implant.

  • Side effects

    Hormonal methods can have side effects. Some people cannot use them for health reasons.

  • Protection

    Only condoms protect against sexually transmitted infections.

  • Permanence

    Sterilisation cannot normally be reversed.

Hormones and fertility treatment (Higher tier)

Some people are infertile, which means they have difficulty conceiving. Hormones can help.

  • Fertility drugs

    A woman who does not release eggs can be given FSH and LH. These make eggs mature in the ovaries and stimulate ovulation.

  • IVF

    In vitro fertilisation means fertilisation in a laboratory dish. It can be used when a couple have not conceived in other ways.

  • Hormones in IVF

    FSH and LH are given to stimulate several eggs to mature, so that more eggs can be collected.

  • Other hormones

    Progesterone may be given after the embryo is put into the uterus, to maintain the lining.

Evaluating IVF (Higher tier)

IVF helps many couples to have a child, but it has disadvantages.

  • Advantage

    It can give a baby to couples who cannot conceive in any other way.

  • Success rate

    Many cycles do not work, and the chance of success falls as the woman gets older.

  • Health risks

    The hormones can have side effects, and putting in more than one embryo can lead to twins or triplets, which carry more risk for the mother and babies.

  • Emotional and financial cost

    Treatment is stressful and can be expensive.

  • Ethical issues

    Some people disagree with the destruction or storage of embryos that are not used.

Case study

Choosing a method of contraception

A young woman wants contraception and looks at the data. The condom, used typically, is less effective than the pill, and the pill is less effective than the implant, because the pill can be forgotten. The implant works for three years without any action needed. But only the condom would protect her against sexually transmitted infections. Her best choice depends on what matters most to her, and on advice from a doctor.

Implant Most effective in the data
Condom The only one that protects against infection

The big idea

Hormonal contraception stops egg release, other methods block sperm or implantation, and for Higher tier hormones such as FSH and LH are also used to treat infertility, as in IVF.

Contraception and fertility

Contraception and fertility

  • Hormonal

    • pill
    • patch
    • injection
    • implant

  • Non-hormonal

    • condom
    • diaphragm
    • IUD
    • abstaining
    • sterilisation

  • Evaluating

    • effectiveness
    • side effects
    • protection
    • permanence

  • Fertility drugs (Higher tier)

    • FSH and LH

  • IVF (Higher tier)

    • eggs fertilised in a dish
    • embryo put into the uterus

Summary and exam focus

  • The combined pill contains oestrogen and progesterone and stops FSH release, so no egg matures.
  • Other hormonal methods use progesterone, as a pill, an injection or an implant.
  • Condoms, diaphragms, IUDs, abstaining and sterilisation are non-hormonal methods.
  • To evaluate a method compare effectiveness, side effects, protection against infection and permanence.
  • (Higher tier) FSH and LH can be given to women who do not ovulate.
  • (Higher tier) IVF fertilises eggs in a dish and puts embryos into the uterus.

Exam focus

Evaluate the use of the combined pill and condoms as methods of contraception. (4 marks) (4 marks)

Give an advantage and a disadvantage for each. Use data if you are given it, for example the number of pregnancies per 100 women, and say that only condoms protect against sexually transmitted infections.

Key terms

The words this lesson expects you to use. Each one is linked from the first place it appears above.

Contraception
A method of preventing pregnancy.
Combined pill
A contraceptive pill containing oestrogen and progesterone.
Implant
A small rod put under the skin that releases progesterone slowly.
Condom
A barrier method that stops sperm reaching an egg and protects against infection.
IUD
A small device put in the uterus that prevents pregnancy.
Infertility
Difficulty in conceiving a child.
IVF
In vitro fertilisation: fertilising an egg with sperm in a laboratory dish (Higher tier).
Embryo
A ball of cells that grows from a fertilised egg.

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