Contraception and Fertility Treatments

This lesson covers the methods of contraception available and the fertility treatments used to help people who struggle to conceive. Understanding both the science and the ethical considerations is important for AQA GCSE Biology, as exam questions may ask you to evaluate different approaches.

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What Is Contraception?

Contraception means preventing pregnancy. There are several methods, which can be grouped into hormonal, barrier, surgical, and other categories.

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Hormonal Methods of Contraception

Hormonal contraceptives work by using synthetic hormones to prevent pregnancy, usually by stopping ovulation or preventing implantation.

Method	How It Works	Effectiveness	Advantages	Disadvantages
The combined pill	Contains oestrogen and progesterone; inhibits FSH so no egg matures; prevents ovulation	Over 99% with perfect use	Highly effective; regulates periods	Must be taken daily; does not protect against STIs; side effects possible
The progesterone-only pill (mini pill)	Contains only progesterone; thickens cervical mucus to prevent sperm reaching egg; may stop ovulation	Over 99% with perfect use	Fewer side effects than combined pill; suitable for more women	Must be taken at the same time daily; does not protect against STIs
The contraceptive injection	Progesterone injected every 8-13 weeks; prevents ovulation	Over 99%	Long-lasting; no daily action needed	Cannot be reversed once injected; possible side effects; does not protect against STIs
The contraceptive implant	Small rod inserted under skin of upper arm; releases progesterone for up to 3 years	Over 99%	Very long-lasting; no daily action	Requires minor procedure to insert/remove; does not protect against STIs
The contraceptive patch	Patch worn on skin releases oestrogen and progesterone; changed weekly	Over 99% with perfect use	Only needs changing weekly	Visible on skin; does not protect against STIs
Intrauterine system (IUS)	T-shaped device placed in uterus; releases progesterone; lasts 3-5 years	Over 99%	Very long-lasting; low maintenance	Requires fitting by a doctor; does not protect against STIs

How Hormonal Contraceptives Work

The hormonal methods prevent pregnancy by:

1. Inhibiting FSH — so no egg matures in the ovaries.
2. Inhibiting LH — so ovulation does not occur.
3. Thickening cervical mucus — making it difficult for sperm to swim through and reach the egg.
4. Thinning the uterus lining — making implantation less likely.

Exam Tip: When explaining how hormonal contraceptives work, always link back to the menstrual cycle hormones. For example: "The pill contains progesterone, which inhibits FSH and LH from the pituitary gland, so no egg matures and ovulation does not occur."

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Non-Hormonal Methods of Contraception

Barrier Methods

Barrier methods physically prevent sperm from reaching the egg.

Method	How It Works	Effectiveness	Advantages	Disadvantages
Male condom	Thin sheath worn over the penis; collects sperm	98% with perfect use	Protects against STIs; readily available; no hormones	Must be used correctly every time; can break or slip
Female condom	Thin pouch inserted into the vagina	95% with perfect use	Protects against STIs; can be inserted in advance	Less widely available; can be displaced during use
Diaphragm/cap	Flexible dome placed over the cervix; used with spermicide	92-96% with perfect use	No hormones; reusable	Must be fitted correctly; does not protect against STIs

Other Non-Hormonal Methods

Method	How It Works	Effectiveness	Advantages	Disadvantages
Intrauterine device (IUD/copper coil)	T-shaped copper device placed in the uterus; copper is toxic to sperm; prevents implantation	Over 99%	Lasts 5-10 years; no hormones	Requires fitting by a doctor; does not protect against STIs; may cause heavier periods
Spermicide	Chemical cream or gel that kills or immobilises sperm	72-82% on its own	No prescription needed	Not effective alone; may cause irritation
Natural family planning	Monitoring body temperature, cervical mucus, and cycle length to identify fertile days; avoiding sex on those days	75-99% depending on accuracy	No hormones or devices; no side effects	Requires careful monitoring and abstinence; less reliable; does not protect against STIs

Surgical Methods

Method	How It Works	Effectiveness	Advantages	Disadvantages
Male sterilisation (vasectomy)	Vas deferens (sperm ducts) are cut and sealed	Over 99%	Permanent; no ongoing action needed	Difficult to reverse; does not protect against STIs
Female sterilisation	Fallopian tubes (oviducts) are cut, sealed, or blocked	Over 99%	Permanent; no ongoing action needed	Requires surgery under general anaesthetic; difficult to reverse; does not protect against STIs

Exam Tip: Remember that only barrier methods (condoms) protect against sexually transmitted infections (STIs). This is a very common exam point. Hormonal methods, IUDs, and surgical methods do not protect against STIs.

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Fertility Treatments

Some couples have difficulty conceiving naturally. Several treatments are available to help.

In Vitro Fertilisation (IVF)

In vitro fertilisation (IVF) literally means "fertilisation in glass". It is a process where eggs are fertilised outside the body and then implanted into the uterus.

Steps of IVF

1. The woman is given FSH and LH (fertility drugs) to stimulate the ovaries to mature multiple eggs at the same time (superovulation).
2. The mature eggs are collected from the ovaries using a fine needle (egg retrieval), guided by ultrasound.
3. Sperm is collected from the male partner or a donor.
4. The eggs and sperm are mixed together in a laboratory dish to allow fertilisation to occur.
5. The fertilised eggs develop into embryos over 2-3 days.
6. One or two healthy embryos are selected and transferred into the woman's uterus (embryo transfer).
7. If an embryo implants successfully in the uterus lining, pregnancy begins.

flowchart TD
    A[FSH and LH given to stimulate ovaries] --> B[Multiple eggs mature]
    B --> C[Eggs collected from ovaries]
    D[Sperm collected from partner or donor] --> E[Eggs and sperm mixed in lab]
    C --> E
    E --> F[Fertilisation occurs]
    F --> G[Embryos develop for 2-3 days]
    G --> H[1-2 embryos transferred to uterus]
    H --> I{Successful implantation?}
    I -->|Yes| J[Pregnancy begins]
    I -->|No| K[Cycle may be repeated]

Success Rates and Limitations of IVF