If a man and a woman have sexual intercourse and do not want to produce a baby, they may use contraception. Explain how different methods of contraception prevent pregnancy.

How to approach this question

This is a 6-mark question, so you need to provide a detailed and structured answer. 1. Start by identifying different categories of contraception (e.g., hormonal, barrier, surgical). 2. For each category, give a specific example (e.g., the pill for hormonal, a condom for barrier). 3. For each example, explain the biological mechanism by which it prevents pregnancy. For example, does it stop the egg being released? Does it stop sperm and egg meeting? Does it stop a fertilised egg implanting? 4. Aim to describe at least three different types of contraception with clear explanations to get full marks.

Full Answer

There are several categories of contraception that work in different ways. **Hormonal methods**, such as the combined pill or contraceptive patch, contain oestrogen and progesterone. These hormones prevent pregnancy primarily by inhibiting ovulation (the release of an egg), so there is no egg to be fertilised. They also thicken cervical mucus to make it difficult for sperm to pass through. **Barrier methods**, like condoms and diaphragms, work by creating a physical barrier. A condom prevents sperm from entering the vagina, while a diaphragm covers the cervix to block sperm from reaching the uterus. This physically stops the sperm and egg from meeting. **Intrauterine devices (IUDs)** are small devices placed in the uterus. A copper IUD releases copper, which is toxic to sperm and prevents implantation of a fertilised egg. A hormonal IUD releases progesterone to thicken cervical mucus and prevent implantation. **Surgical methods** offer a permanent solution. In a vasectomy (male sterilisation), the sperm ducts are cut and tied, so sperm cannot be released during ejaculation. In female sterilisation, the fallopian tubes are cut or blocked, so the egg cannot travel to the uterus to be fertilised. **Natural methods** involve avoiding intercourse during the woman's fertile period, identified by tracking the menstrual cycle. This is less reliable as ovulation can be unpredictable.

Contraception refers to methods used to prevent pregnancy. They work through various biological mechanisms: - **Hormonal Methods (e.g., the Pill, patch, injection):** These contain hormones like oestrogen and progesterone. Their main function is to inhibit the pituitary gland from releasing FSH and LH. Without LH, ovulation (the release of an egg) does not occur. With no egg available, fertilisation is impossible. They also cause the mucus in the cervix to thicken, making it harder for sperm to swim through to the uterus. - **Barrier Methods (e.g., condoms, diaphragm):** These create a physical block. A male condom is worn on the penis and collects semen, preventing sperm from entering the vagina. A diaphragm is placed over the cervix, blocking sperm from entering the uterus. Their function is simply to prevent the sperm and egg from meeting. - **Intrauterine Methods (IUD/IUS):** An IUD is a small T-shaped device inserted into the uterus. A copper IUD releases copper ions which are toxic to sperm and also prevent a fertilised egg from implanting in the uterus wall. An IUS (hormonal IUD) releases progesterone, which thickens cervical mucus and thins the uterus lining, preventing implantation. - **Surgical Methods (Sterilisation):** These are permanent methods. A vasectomy in males involves cutting and sealing the sperm ducts, so sperm is not present in the ejaculated semen. Female sterilisation involves cutting or blocking the fallopian tubes, so the egg cannot travel from the ovary to the uterus, and sperm cannot reach the egg.

Common mistakes

✗ Confusing the mechanisms, e.g., saying condoms release hormones. ✗ Not giving enough detail for a 6-mark question, e.g., just listing methods without explaining how they work. ✗ Vague explanations like "the pill stops you getting pregnant" without saying how (by stopping ovulation).

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If a man and a woman have sexual intercourse and do not want to produce a baby, they may use contraception. Explain how different methods of contraception prevent pregnancy.

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Common mistakes

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