How Does Contraception Work? Hormonal and Non-Hormonal

Contraception helps prevent pregnancy. Hormonal methods use hormones to stop an egg maturing or being released. Non-hormonal methods can prevent sperm reaching an egg, prevent an embryo implanting, or prevent sperm and eggs from meeting in other ways.

Hormonal methods

The oral contraceptive pill contains hormones that inhibit production of follicle-stimulating hormone (FSH). FSH normally helps an egg mature, so inhibiting it means no egg matures.

An injection, implant or skin patch can slowly release progesterone. This inhibits the maturation and release of eggs for a number of months or years.

Non-hormonal methods

Barrier methods, such as condoms and diaphragms, prevent sperm reaching an egg. Spermicides kill or disable sperm. Avoiding intercourse when an egg may be in the oviduct is another method; the oviduct is the tube through which an egg travels from the ovary. Sterilisation is a surgical method that prevents sperm and eggs from meeting.

An intrauterine device (IUD) is placed in the uterus. Depending on the type, it may prevent an embryo implanting or release a hormone. That means you should not describe every IUD as non-hormonal.

For example, if a question names a condom, explain that it forms a barrier so sperm cannot reach an egg. If it names an oral contraceptive, explain that its hormones inhibit FSH production, so an egg does not mature. Both help prevent pregnancy, but they work in different ways: one blocks sperm, while the other affects egg maturation.

Exam mistake to avoid: Do not say that all contraception works by stopping fertilisation. Fertilisation is when a sperm joins an egg. Some methods stop an egg being released, while others prevent sperm reaching it or prevent an embryo implanting. Match your explanation to the method named in the question.

This covers contraception in AQA GCSE Biology (separate science) and applies at both Foundation and Higher tier.