Contraception Methods IGCSE Biology 0610

Contraception Methods: Preventing Pregnancy

Biology editorial review is supported by the named review panel. Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.

Key concept

Contraception prevents pregnancy. Methods include mechanical barriers (condoms, femidoms) that prevent sperm reaching the egg, hormonal methods (the pill) that prevent ovulation, and chemical methods (spermicides) that kill sperm.

Contraception questions test whether students understand the biological mechanism of each method, not just what it is called. Linking each method to the specific stage of reproduction it prevents is the key to full marks.

Mechanical (barrier) methods

Condoms (male and female) are physical barriers that prevent sperm from reaching the egg. They also reduce the transmission of sexually transmitted infections (STIs). The mechanism is simple: if sperm cannot enter the oviduct, fertilisation cannot occur.

Other barrier methods include the diaphragm, which covers the cervix and blocks sperm from entering the uterus. Barrier methods have no hormonal side effects and are the only contraceptive methods that also protect against STIs.

Hormonal methods

Hormonal contraceptives such as the combined oral contraceptive pill contain synthetic oestrogen and progesterone. These hormones prevent ovulation by inhibiting the release of FSH and LH from the pituitary gland. Without ovulation, there is no egg to be fertilised.

Progesterone-only methods also thicken the cervical mucus, making it more difficult for sperm to pass through, and thin the uterus lining, making implantation less likely. Hormonal implants and injections work on the same principles but deliver hormones over longer periods.

Chemical methods and IUDs

Spermicides are chemical substances that kill or immobilise sperm. They are often used alongside barrier methods for increased effectiveness. On their own, spermicides are less reliable.

An intrauterine device (IUD) is inserted into the uterus. Copper IUDs release copper ions that are toxic to sperm and also make the uterus lining unsuitable for implantation. Hormonal IUDs release progesterone locally, thickening cervical mucus and thinning the uterus lining.

Abstinence and natural methods

Abstinence (avoiding sexual intercourse) is the only method that is 100% effective at preventing pregnancy and STI transmission. Natural family planning involves tracking the menstrual cycle and avoiding intercourse during the fertile window around ovulation.

Natural methods require careful monitoring of cycle length, body temperature and cervical mucus changes. They are less reliable than other methods because cycles can be irregular and sperm can survive in the female reproductive tract for several days.

Try a focused question (3 marks)

Explain how the contraceptive pill prevents pregnancy.

Show the answer and marking guidance

The pill contains hormones (oestrogen and/or progesterone).
These hormones inhibit FSH/LH release from the pituitary gland, preventing ovulation.
Without ovulation, no egg is released, so fertilisation cannot occur.

Original Cambridge-style practice written for this site. It is not an official Cambridge past-paper question.

Common mix-ups to avoid

Check these points against your own answer before moving on.

Saying the pill kills sperm (it prevents ovulation; spermicides kill sperm).
Forgetting that condoms also protect against STIs, not just pregnancy.
Describing the pill as a barrier method rather than a hormonal method.
Not explaining the mechanism (just naming the method without saying how it works).